JP2005505785A - Molecular mechanical devices whose band gap changes are facilitated by an electric field for optical switching applications - Google Patents

Abstract

Molecular systems (430, 630, 630 ′, 730) for electric field driven switches such as optical switches (101, 205, 207, 209) are provided. The molecular system (430, 630, 630 ′, 730) can be used to (1) change the molecular conformation, (2) change the extended conjugation via a chemical bond change that changes the band gap, or (3) One mechanism of elongation causes a field-induced bandgap change. That is, various optical switches (101, 205, 207, 209) that can be combined to easily form various optical devices including optical displays (100, 200, 300) are combined to easily form. A nanometer-scale reversible optical switch is provided.

Description

Ｃｏｎ_１−接続基
Ｃｏｎ_２−接続基
ＳＢ−固定子Ｂ
ＳＡ−固定子Ａ
Ａ⁻−受容体（電子求引基）
Ｄ^＋−供与体（電子供与基）
【００５２】
ここで、文字Ａ⁻は、受容体基を表し、それは電子求引基である。それは、水素、カルボン酸あるいはその誘導体、硫酸あるいはその誘導体、リン酸あるいはその誘導体、ニトロ、ニトリル、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｆ、Ｃｌ、Ｂｒ）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＯＨ、ＳＨ、ＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）あるいは置換炭化水素、のうちの１つとすることができる。
【００５３】
文字Ｄ^＋は、供与体基を表し、それは電子供与基である。それは、水素、アミン、ＯＨ、ＳＨ、エーテル、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、あるいは少なくとも１つのヘテロ原子（例えば、Ｂ、Ｓｉ、Ｎ、Ｏ、Ｓ、Ｐ、Ｉ）を有する官能基のうちのいずれか１つとすることができる。供与体は、当該分子上の受容体基よりも電気的陰性が低いか、あるいは電気的陽性が高いという事実によって受容体とは区別される。
【００５４】
文字Ｃｏｎ_１及びＣｏｎ_２は、ある分子と他の分子との間の、又はある分子と固体基材（例えば、金属電極、無機あるいは有機基材等）との間の、接続ユニットを表す。それらは、水素（水素結合を利用する）、多価へテロ原子（即ち、Ｃ、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいはこれらのヘテロ原子を含む官能基（例えば、ＮＨ、ＰＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素のうちの任意のものとすることができる。
【００５５】
文字ＳＡ及びＳＢはここでは固定子Ａ及び固定子Ｂを示すために用いられる。それらは、炭化水素（飽和あるいは不飽和のいずれか）あるいは置換炭化水素とすることができる。典型的には、これらの炭化水素ユニットは、平面状態（赤方偏移状態）にあるときに、分子の拡張共役に寄与する共役環を含有する。それらの固定子ユニットにおいては、それらはブリッジング基Ｇ_ｎ及び／又はスペーシング基Ｒ_ｎを含むことができる。ブリッジング基（例えば、アセチレン、エチレン、アミド、イミド、イミン、アゾ等）は、典型的に、固定子を回転子に接続するか、又は２つ以上の共役環を接続し所望の発色団を得るために用いられる。あるいは又、該コネクタは、酸素原子によるエーテルブリッジのような単原子ブリッジか、又は回転子と固定子との間の直接σ結合から構成することができる。スペーシング基（例えば、フェニル、イソプロピルあるいはｔ−ブチル等）は、各回転子が所望の動作範囲にわたって回転するための空間を設けながら、分子が密集できるようにするための、適切な３次元の枠組みを設けるのに用いられる。
【００５６】
以下の例１ｂは、モデル１の実際の分子の例である。実施例１ｂでは、回転子の回転軸が、分子の正味の電流搬送軸に概ね垂直になるように設計されているが、一方、例２では、回転軸は、分子の方位軸に平行になっている。これらの設計によって、所望する結果に応じて、使用される分子膜及び電極を種々の構造にすることが可能となる。
【００５７】
【化２】

【００５８】
ここで、文字Ａ⁻は、受容体基を表し、それは電子求引基である。それは、水素、カルボン酸あるいはその誘導体、硫酸あるいはその誘導体、リン酸あるいはその誘導体、ニトロ、ニトリル、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｆ、Ｃｌ、Ｂｒ）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＯＨ、ＳＨ、ＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）あるいは置換炭化水素、のうちの１つとすることができる。
【００５９】
文字Ｄ^＋は、供与体基を表し、それは電子供与基である。それは、水素、アミン、ＯＨ、ＳＨ、エーテル、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、あるいは少なくとも１つのヘテロ原子（例えば、Ｂ、Ｓｉ、Ｎ、Ｏ、Ｓ、Ｐ、Ｉ）を有する官能基、のうちの１つとすることができる。供与体は、当該分子上の受容体基よりも電気的陰性が低いか、あるいは電気的陽性が高いという事実によって、受容体とは区別される。
【００６０】
文字Ｃｏｎ_１及びＣｏｎ_２は、ある分子と他の分子、又はある分子と固体基材（例えば、金属電極、無機あるいは有機基材等）との間の接続ユニットを表す。それらは、水素（水素結合を利用する）、多価へテロ原子（即ち、Ｃ、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいはこれらのヘテロ原子を含む官能基（例えば、ＮＨ、ＰＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素のうちの任意のものとすることができる。
【００６１】
文字Ｒ_１、Ｒ_２、Ｒ_３は、分子に組み込まれているスペーシング基を表す。これらスペーサーユニットの機能は、各回転子のための回転の空間を設けながら、分子が密集できるようにするための、適切な３次元の枠組みを設けることである。それらは、水素、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【００６２】
文字Ｇ_１、Ｇ_２、Ｇ_３及びＧ_４は、ブリッジング基である。これらブリッジング基の機能は、所望の発色団を得るために、固定子と回転子とを接続するか、又は２つ以上の共役環を接続することである。それらは、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいは上記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＮＨあるいはＮＨＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。あるいは又、該コネクタは、酸素原子によるエーテルブリッジのような単原子ブリッジ、又は回転子と固定子との間の直接シグマ結合により構成することができる。
【００６３】
上記の例１ｂにおいて、垂直方向の点線は、他の分子あるいは固体基材を表す。スイッチング電界の向きは、前記垂直方向の点線に対して垂直である。そのような構成は、電気的なスイッチングのために用いられる。光学的なスイッチングの場合，結合部はなくすことができ、分子を単に２つの電極間に配置することができる。それらは又、単に、ある分子を他の分子に結合させるか、又はある分子を有機あるいは無機固体基材に結合させることもできる。図５ａを参照すると、上記の分子（例１ｂ）は、内部回転子４３２が分子４３０全体の方位軸に対して垂直になるように設計されている。この場合、外部電界は図示するように分子４３０の方位軸に沿って印加され、電極（垂直方向の破線）は紙面に対して垂直に、且つ分子４３０の方位軸に対して垂直に向けられる。図面の左から右に配向された電界の印加によって、上側の図面に描かれたような回転子４３２を下側右の図面に示す位置まで回転させることができ、またその逆も可能である。この場合、下側右の図面に描かれたような回転子４３２は、分子の他の部分と同一平面上になく、そのため、これは分子の青方偏移光学状態であり、一方、上側の図面では回転子が分子の他の部分と同一平面上にあるので、これは分子の赤方偏移光学状態である。下側左の図面に示した構造は、上側の図面（同一平面、共役）と下側右の図面（中央部分が回転、非共役）との間の回転の移行の様子を表している。
【００６４】
例１ｂに示す分子は、透明色であるか、又は青方偏移している。共役状態では、分子は有色であるか、又は赤方偏移している。
【００６５】
例１ｂに示す分子の場合、例えばラングミュア−ブロジェット法あるいは自己組織化単層を使って、単一の単層分子膜を成長させて、それによって、分子の方位軸が、分子を切り替えるのに使用される電極面に垂直になるようにする。電極は、上記のＣｏｌｌｉｅｒらによって示された方法で、又は前述の関連特許出願及び発行特許に記載された方法で、付着させることができる。別のより厚い薄膜の付着技術には、気相成長法、コンタクト法あるいはインクジェットプリンティング法、あるいはシルクスクリーン法が含まれる。
【００６６】
下記の例２ａは、本モデル１のための第２の一般的な分子の例を示している。
【００６７】
【化３】

Ｃｏｎ_１−接続基
Ｃｏｎ_２−接続基
ＳＢ−固定子Ｂ
ＳＡ−固定子Ａ
Ａ⁻−受容体（電子求引基）
Ｄ^＋−供与体（電子供与基）
【００６８】
ここで、文字Ａ⁻は、受容体基を表し、それは電子求引基である。それは、水素、カルボン酸あるいはその誘導体、硫酸あるいはその誘導体、リン酸あるいはその誘導体、ニトロ、ニトリル、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｆ、Ｃｌ、Ｂｒ）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＯＨ、ＳＨ、ＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの１つとすることができる。
【００６９】
文字Ｄ^＋は、供与体基を表し、それは電子供与基である。それは、水素、アミン、ＯＨ、ＳＨ、エーテル、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、あるいは少なくとも１つのヘテロ原子（例えば、Ｂ、Ｓｉ、Ｉ、Ｎ、Ｏ、Ｓ、Ｐ）を有する官能基、のうちのいずれか１つとすることができる。供与体は、当該分子上の受容体基よりも電気的陰性が低いか、あるいは電気的陽性が高いという事実によって受容体とは区別される。
【００７０】
文字Ｃｏｎ_１及びＣｏｎ_２は、ある分子と他の分子との間の、又はある分子と固体基材（例えば、金属電極、無機あるいは有機基材等）との間の接続ユニットを表す。それらは、水素（水素結合を利用する）、多価へテロ原子（即ち、Ｃ、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいはこれらヘテロ原子を含む官能基（例えば、ＮＨ、ＰＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【００７１】
文字ＳＡ及びＳＢは、ここでは固定子Ａ及び固定子Ｂを示すために用いられる。それらは、炭化水素（飽和あるいは不飽和のいずれか）あるいは置換炭化水素とすることができる。典型的には、これらの炭化水素ユニットは、平面状態（赤方偏移状態）にあるときに、分子の拡張共役に寄与する共役環を含む。それら固定子ユニットにおいては、それらはブリッジング基Ｇ_ｎ及び／又はスペーシング基Ｒ_ｎを含むことができる。ブリッジング基は、典型的に、固定子と回転子とを接続するか、あるいは２つ以上の共役環を接続させ所望の発色団を得るために用いられる。あるいは又、該コネクタは、酸素原子によるエーテルブリッジのような単原子ブリッジか、又は回転子と固定子との間の直接σ結合から構成することができる。スペーシング基は、各回転子が回転するための空間を設けながら、分子が密集できるようにするための適切な３次元の枠組みをもたらす。
【００７２】
下記の例２ｂは、モデル１の他の実際の分子の例である。
【００７３】
【化４】

【００７４】
ここで、文字Ａ⁻は、受容体基を表し、それは電子求引基である。それは、水素、カルボン酸あるいはその誘導体、硫酸あるいはその誘導体、リン酸あるいはその誘導体、ニトロ、ニトリル、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｆ、Ｃｌ、Ｂｒ）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＯＨ、ＳＨ、ＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの１つとすることができる。
【００７５】
文字Ｄ^＋は、供与体基を表し、それは電子供与基である。それは、水素、アミン、ＯＨ、ＳＨ、エーテル、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、あるいは少なくとも１つのヘテロ原子（例えば、Ｂ、Ｓｉ、Ｉ、Ｎ、Ｏ、Ｓ、Ｐ）を有する官能基、のうちの１つとすることができる。供与体は、当該分子上の受容体基よりも電気的陰性が低いか、あるいは電気的陽性が高いという事実によって受容体とは区別される。
【００７６】
文字Ｃｏｎ_１及びＣｏｎ_２は、ある分子と他の分子との間の、又はある分子と固体基材（例えば、金属電極、無機あるいは有機基材等）との間の接続ユニットを表す。それらは、水素（水素結合を利用する）、多価へテロ原子（即ち、Ｃ、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいはこれらのヘテロ原子を含む官能基（例えば、ＮＨ、ＰＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【００７７】
文字Ｒ_１、Ｒ_２及びＲ_３は、分子に組み込まれているスペーシング基を表す。これらのスペーサユニットの機能は、各回転子のための回転の空間を設けながら、分子が密集できるようにするための適切な３次元の枠組みを設けることである。それらは、水素、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【００７８】
文字Ｇ_１、Ｇ_２、Ｇ_３、Ｇ_４、Ｇ_５、Ｇ_６、Ｇ_７及びＧ_８は、ブリッジング基を表す。これらのブリッジング基の機能は、所望の発色団を得るために、固定子と回転子とを接続するか、又は２つ以上の共役環を接続することである。それらは、ヘテロ原子（例えば、Ｃ、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＮＨあるいはＮＨＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。あるいは又、該コネクタは、酸素原子によるエーテルブリッジのような単原子ブリッジ、又は回転子と固定子との間の直接シグマ結合から構成することができる。
【００７９】
文字Ｊ_１及びＪ_２は分子に組み込まれている調整基を表す。これらの調整基（例えば、ＯＨ、ＮＨＲ、ＣＯＯＨ、ＣＮ、ニトロ等）の機能は、適切な機能的効果（例えば、誘導性効果及び共鳴効果の両方）及び／又は立体効果をもたらすことである。機能的効果とは、分子のバンドギャップ（ΔＥ_{ＨＯＭＯ／ＬＵＭＯ}）を調整し、分子の光学的特性だけではなく、所望の電子的特性を得ることである。立体効果とは、立体障害、分子間あるいは分子内相互作用力（例えば、水素結合、クーロン相互作用、ファンデルワールス力）を介して分子配座を調整することや、あるいは分子の方位の双安定性あるいは多重安定性をもたらすことである。それらは、水素、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｂ、Ｆ、Ｃｌ、Ｂｒ及びＩ）、前記ヘテロ原子のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和炭化水素のいずれか）あるいは置換炭化水素、のうちの任意のものとすることができる。
【００８０】
上記分子（例２ｂ）は、分子全体の方位軸に平行な内部回転子を用いて設計されている。この場合、外部電界は、分子軸に垂直に印加される。電極は、分子の長軸に平行に配向され、且つ表面上、上記モデル構造の面に垂直か又は平行に配向させることができる。例えば、電界線が分子軸に対して垂直で且つ上方を指している電界を上記上側分子へ印加することによって、その図に描かれている回転子は、上記下側分子図面に示すように、ほぼ９０°回転し、エッジが現出する。この逆も可能である。この場合、下側図面に描かれたような回転子は、分子の他の部分と同一面上になく、そのため、これは分子の青方偏移光学状態、即ち光学状態ＩＩであり、一方、上側図面では、回転子が分子の他の部分と同一面上にあり、そのため、これは分子の赤方偏移光学状態、即ち光学状態Ｉである（記号Ｎ、Ｈ及びＯはそれらの通常の意味を有する）。
【００８１】
図５ａは、例１ｂ及び２ｂの分子に類似のものであるが、さらに簡単であり、中央回転子部４３２及び２つの端部固定子部４３４からなる。例１ｂ及び２ｂにおいてと同様に、回転子部４３２は、双極子を有する回転子となる置換基を設けられたベンゼン環からなる。２つの固定子部４３４の各々は、アゾ結合を介してベンゼン環に共有結合されており、且つ両方の部分とも、芳香環からなっている。
【００８２】
図５ｂは、回転子４３２及び固定子４３４が全て同一面上にある平坦な状態を示している概略図（斜視図）である。該平坦な状態では、分子４３０は完全に共役されており、色（第１のスペクトルあるいは光学状態）を明白に示し、比較的導電率が高い。環の共役を、それぞれ分子４３０の面の上及び下にあるπ軌道の雲５００ａ及び５００ｂによって示す。
【００８３】
図５ｃは、回転した状態を示す概略図（斜視図）であり、回転子４３２が固定子４３４に関して９０°回転しており、固定子は依然として同一平面上にある。該回転した状態では、分子４３０の共役が破壊されている。結果として、分子４３０は透明（第２のスペクトルあるいは光学状態）になり、比較的導電率が低くなる。
【００８４】
例２ｂの分子に関しては、分子軸が電極面に対して平行になるように薄膜を形成させる。これによって、多数の単層が重なり合った膜が生じる。分子は、固体結晶あるいは液晶を形成し、大きい固定子基は分子間相互作用あるいは支持構造への直接結合によって所定の位置に固定されるが、回転子は分子の格子内部で十分移動できるほど小さい。このタイプの構造は、電界制御式のディスプレイを形成するために用いることができるか、あるいは本明細書において先に記載したような他の用途のために用いることができる。
【００８５】
モデル（２ａ）：バンド局在化の増減を伴う電荷の分離あるいは再結合を介した拡張共役の変化によって引き起こされる電界誘導性バンドギャップ変化
図６ａは、本モデルの概略図であり、それはバンド局在化の増減を伴う電荷の分離あるいは再結合を介した拡張共役の変化によって引き起こされる電界誘導バンドギャップ変化を伴うものである。図６ａに示すように、分子６３０は、２つの部分６３２及び６３４からなる。分子６３０は、π非局在化が少なく、比較的大きいバンドギャップを示す。電界の印加によって、分子６３０内での電荷の分離が起こり、π非局在化が十分となり、バンドギャップがより小さい状態になる。電荷の再結合によって、分子６３０はその元の状態に戻る。
【００８６】
本モデルでは、下記要件が満たされなければならない。
（ａ）当該分子は、適度の誘電率ε_τを有し、外部電界によって容易に分極されることができなければならない。ε_τは２〜１０の範囲にあり、且つ分極電界は０．０１〜１０Ｖ／ｎｍの範囲にある。
（ｂ）分子の少なくとも１つの部位が、該分子全体あるいは一部にわたって移動することができる、非結合電子、あるいはπ電子、あるいはπ電子及び非結合電子を有していなければならない。
（ｃ）当該分子は、対称性あるいは非対称性とすることができる。
（ｄ）分子の誘導性双極子（単数又は複数）は、少なくとも１つの方向を向かせることができる。
（ｅ）電界誘導分極の間、電荷が部分的にあるいは完全に分離される。
（ｆ）電荷の分離あるいは再結合の状態が電界依存性あるいは双安定性であり、例えば共有結合形成、水素結合、電荷引力、クーロン力、金属錯体、あるいはルイス酸（塩基）錯体等のような分子内あるいは分子間力によって安定化させることができる。
（ｇ）分子の電荷分離あるいは再結合の過程が、σ結合及びπ結合の破壊あるいは形成を伴っても、伴わなくてもよい。
（ｈ）電界によって促進される電荷の分離あるいは再結合過程の間、分子のバンドギャップが、非結合電子、あるいはπ電子、あるいはπ電子及び非結合電子の分子内での非局在化の程度に依存して変化する。分子の光学的及び電気的な特性の両方が、それに応じて変化する。
【００８７】
結合の破壊あるいは結合の形成を伴う電荷の分離あるいは再結合を介した電界誘導バンドギャップ変化（色の変化）の一例を以下（例３）に示す。
【００８８】
【化５】

【００８９】
ここで、文字Ｊ_１、Ｊ_２、Ｊ_３、Ｊ_４及びＪ_５は分子に組み込まれている調整基を表す。これらの調整基（例えば、ＯＨ、ＮＨＲ、ＣＯＯＨ、ＣＮ、ニトロ等）の機能は、適切な機能的効果（例えば、誘導性効果及び共鳴効果の両方）及び／又は立体効果をもたらすことである。機能的効果とは、分子のバンドギャップ（ΔＥ_{ＨＯＭＯ／ＬＵＭＯ}）を調整し、分子の所望の光学的特性だけではなくて、所望の電子的特性も得ることである。立体効果とは、立体障害、分子間あるいは分子内相互作用力（例えば、水素結合、クーロン相互作用、ファンデルワールス力）を介して分子配座を調整することや、あるいは分子の方位の双安定性あるいは多重安定性を与えることである。それらは、水素、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｂ、Ｆ、Ｃｌ、Ｂｒ及びＩ）、前記ヘテロ原子のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【００９０】
文字Ｇ_１は、ブリッジング基である。該ブリッジング基の機能は、所望の発色団を得るために、２つ以上の共役環を接続することである。ブリッジング基は、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ等）あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えばＮＨ等）、炭化水素あるいは置換炭化水素、のうちの任意のものとすることができる。
【００９１】
文字Ｗは、電子求引基である。この基の機能は、当該分子の無水マレイン酸基の反応を調整することであり、それは、印加された外部電界の影響下で、当該分子が円滑な電荷分離あるいは再結合（結合の破壊あるいは形成等）されるのを可能とする。該電子求引基は、カルボン酸あるいはその誘導体（例えば、エステルあるいはアミド等）、ニトロ、ニトリル、ケトン、アルデヒド、スルホン、硫酸あるいはその誘導体、ヘテロ原子（例えば、Ｆ、Ｃｌ等）あるいは少なくとも１つのヘテロ原子（例えば、Ｆ、Ｃｌ、Ｂｒ、Ｎ、Ｏ、Ｓ等）を有する官能基、のうちの任意のものとすることができる。
【００９２】
分子−金属錯体あるいは分子−ルイス酸錯体の形成を伴う電界誘導バンドギャップ変化の一例を以下に示す（例４）。
【００９３】
【化６】

【００９４】
ここで、文字Ｊ_１、Ｊ_２、Ｊ_３、Ｊ_４及びＪ_５は、分子に組み込まれている調整基を表す。これらの調整基（例えば、ＯＨ、ＮＨＲ、ＣＯＯＨ、ＣＮ、ニトロ等）の機能は、適切な機能的効果（例えば、誘導性効果及び共鳴効果の両方）及び／又は立体効果をもたらすことである。機能的効果とは、分子のバンドギャップ（ΔＥ_{ＨＯＭＯ／ＬＵＭＯ}）を調整し、分子の所望の光学的特性だけではなく、電子的特性も得ることである。立体効果とは、立体障害、分子間あるいは分子内相互作用力（例えば、水素結合、クーロン相互作用、ファンデルワールス力）を介して分子配座を調整することや、あるいは分子の向きの双安定性あるいは多重安定性をもたらすことである。それらは、水素、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｂ、Ｆ、Ｃｌ、Ｂｒ及びＩ）、前記ヘテロ原子のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【００９５】
記号Ｇ_１は、ブリッジング基である。ブリッジング基の機能は、所望の発色団を得るために、２つ以上の共役環を接続することである。ブリッジング基は、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ等）あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えばＮＨ等）、炭化水素あるいは置換炭化水素、のうちの任意のものとすることができる。
【００９６】
Ｍ^＋は、遷移金属を含む金属、あるいはそれらのハロゲン錯体、あるいはＨ^＋、あるいは他の種類のルイス酸（単数又は複数）である。
【００９７】
モデル（２ｂ）：電荷の分離あるいは再結合、及びπ結合の破壊あるいは形成を介した拡 張共役の変化によって引き起こされる電界誘導性バンドギャップ変化
図６ｂは、本モデルの概略図であり、それは電荷の分離あるいは再結合及びπ結合の破壊あるいは形成を介した拡張共役の変化によって引き起こされる電界誘導バンドギャップの変化を伴う。図６ｂに示すように、分子６３０’は、２つの部分６３２’及び６３４’からなる。分子６３０’は、比較的小さいバンドギャップを示す。電界の印加によって、分子６３０’内のπ結合の破壊が起こり、その結果バンドギャップがより大きい状態になる。電界を反転させることで、２つの部分６３２’及び６３４’の間にπ結合が再結合され、分子６３０’がその元の状態に戻る。
【００９８】
本モデルにおいて満たさなければならない要件は、モデル２（ａ）に関して挙げたものと同じである。
【００９９】
電荷の分離（σ結合の破壊及びπ結合の形成）を介する拡張共役の変化によって引き起こされる電界誘導バンドギャップ変化の一例を以下（例５）に示す。
【０１００】
【化７】

【０１０１】
ここで、文字Ｑは、２つのフェニル環間の接続ユニットを示すために用いられる。接続ユニットは、Ｓ、Ｏ、ＮＨ、ＮＲ、炭化水素あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１０２】
文字Ｃｏｎ_１及びＣｏｎ_２は、ある分子と他の分子との間の、又はある分子と固体基材（例えば、金属電極、無機あるいは有機基材等）との間の接続ユニットを表す。それらは、水素（水素結合によって）、へテロ原子（即ち、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいは前記ヘテロ原子の少なくとも１つを含む官能基（例えば、ＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１０３】
文字Ｒ_１及びＲ_２は、分子に組み込まれているスペーシング基を表す。これらのスペーサユニットの機能は、各回転子のための回転の空間を設けながら、分子が密集できるようにするための適切な３次元の枠組みを設けることである。それらは、水素、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１０４】
文字Ｊ_１、Ｊ_２、Ｊ_３及びＪ_４は分子に組み込まれている調整基を表す。これらの調整基（例えば、ＯＨ、ＮＨＲ、ＣＯＯＨ、ＣＮ、ニトロ等）の機能は、適切な機能的効果（例えば、誘導性効果及び共鳴効果の両方）及び／又は立体効果を与えることである。機能的効果とは、分子のバンドギャップ（ΔＥ_{ＨＯＭＯ／ＬＵＭＯ}）を調整し、分子の所望の光学的特性だけではなくて、電子的特性も得ることである。立体効果とは、立体障害、分子間あるいは分子内相互作用力（例えば、水素結合、クーロン相互作用、ファンデルワールス力）を介して分子配座を調整し、分子の向きの双安定性あるいは多重安定性をもたらすことである。また、それらをスペーシング基として用いて適切な３次元の枠組みを設けることができ、各回転子のための回転の空間を設けながら、分子を密集させることができる。それらは、水素、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｂ、Ｆ、Ｃｌ、Ｂｒ及びＩ）、少なくとも１つの前記ヘテロ原子を有する官能基、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１０５】
文字Ｇ_１は、ブリッジング基である。ブリッジング基の機能は、所望の発色団を得るために、固定子と回転子を接続するか、又は２つ以上の共役環を接続することである。ブリッジング基は、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＮＨ又はＮＨＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１０６】
文字Ｗは、電子求引基である。この基の機能は、当該分子のラクトン基の反応性を調整し、印加された外部電界の影響下で、分子を円滑に電荷分離あるいは再結合（結合破壊あるいは形成等）させるようにすることである。電子求引基は、カルボン酸あるいはその誘導体（例えば、エステルあるいはアミド等）、ニトロ、ニトリル、ケトン、アルデヒド、スルホン、硫酸あるいはその誘導体、ヘテロ原子（例えば、Ｆ、Ｃｌ等）、あるいは前記ヘテロ原子（例えば、Ｆ、Ｃｌ、Ｂｒ、Ｎ、Ｏ、Ｓ等）のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和炭化水素のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１０７】
最も上側の分子構造は、最も下側の分子構造よりも比較的小さいバンドギャップ状態を有する。
【０１０８】
電荷の再結合及びσ結合の形成を介する拡張π結合共役の破壊によって引き起こされる電界誘導バンドギャップ変化の他の例を以下に示す（例６）。
【０１０９】
【化８】

【０１１０】
ここで、文字Ｑは、２つのフェニル環間の接続ユニットを示すために用いられる。接続ユニットは、Ｓ、Ｏ、ＮＨ、ＮＲ、炭化水素あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１１１】
文字Ｃｏｎ_１及びＣｏｎ_２は、ある分子と他の分子との間の、又はある分子と固体基材（例えば、金属電極、無機あるいは有機基材等）との間の接続基である。それらは、水素、へテロ原子（即ち、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいは前記ヘテロ原子のうちの少なくとも１つを含む官能基（例えばＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１１２】
文字Ｒ_１及びＲ_２は、分子に組み込まれているスペーシング基を表す。これらのスペーサユニットの機能は、各回転子のための回転の空間を設けながら、分子が密集できるようにするための適切な３次元の枠組みを設けることである。それらは、水素、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１１３】
文字Ｊ_１、Ｊ_２、Ｊ_３及びＪ_４は、分子に組み込まれている調整基を表す。これらの調整基（例えば、ＯＨ、ＮＨＲ、ＣＯＯＨ、ＣＮ、ニトロ等）の機能は、適切な機能的効果（例えば、誘導性効果及び共鳴効果の両方）及び／又は立体効果をもたらすことである。機能的効果とは、分子のバンドギャップ（ΔＥ_{ＨＯＭＯ／ＬＵＭＯ}）を調整し、分子の所望の光学的特性だけではなくて、電子的特性も得ることである。立体効果とは、立体障害、分子間あるいは分子内相互作用力（例えば、水素結合、クーロン相互作用、ファンデルワールス力）を介して分子配座を調整して、分子の向きの双安定性あるいは多重安定性をもたらすことである。また、それらをスペーシング基として用いて適切な３次元の枠組みを設けることができ、各回転子のための回転の空間を設けながら、分子を密集させることができる。それらは、水素、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｂ、Ｆ、Ｃｌ、Ｂｒ及びＩ）、前記ヘテロ原子のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１１４】
文字Ｇ_１は、ブリッジング基である。ブリッジング基の機能は、所望の発色団を得るために、固定子及び回転子を接続するか、又は２つ以上の共役環を接続することである。ブリッジング基は、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ等）、あるいは前記ヘテロ原子のうちの少なくとも１つを有する官能基（例えば、ＮＨ又はＮＨＮＨ等）、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１１５】
文字Ｗは、電子求引基である。この基の機能は、当該分子のラクトン基の反応性を調整し、印加された外部電界の影響下で、分子を円滑に電荷の分離あるいは再結合（結合の破壊あるいは形成等）させるようにすることである。電子求引基は、カルボン酸あるいはその誘導体（例えば、エステルあるいはアミド等）、ニトロ、ニトリル、ケトン、アルデヒド、スルホン、硫酸あるいはその誘導体、ヘテロ原子（例えば、Ｆ、Ｃｌ等）、あるいは前記ヘテロ原子（例えば、Ｆ、Ｃｌ、Ｂｒ、Ｎ、Ｏ、Ｓ等）のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１１６】
重ねて、最も上側の分子構造は、最も下側の分子構造よりも比較的小さいバンドギャップ状態を有する。
【０１１７】
本発明は、インクあるいは染料分子を、任意の前述のエレクトロクロミック材料あるいはクロモジェニック材料とは全く異なるメカニズムによって、外部電界を用いて切り替えることのできる能動デバイスにする。全般的な概念は、変性されたクリスタルバイオレットラクトンタイプの分子を利用することであり、そこでは、ラクトンのＣ−Ｏ結合が十分に不安定であり、印加される電界の影響下で、該結合の破壊及び形成（上記の例５及び６参照）をさせることができる。
【０１１８】
Ｃ−Ｏ結合の破壊過程において、正及び負の電荷が生成される。生じた電荷は分離し印加外部電界に対して平行に逆方向に移動する（分子の上側部分）か、あるいは結合回転（分子の下側部分）が起こる。分子の拡張双極子を有する２つの芳香環（上側及び下側部分）は完全に共役され、色（赤方偏移）が生じる（例５参照）。しかしながら、当該分子は、例えば水素結合、クーロン力、あるいは双極子−双極子相互作用及び立体斥力のような、分子間及び／又は分子内力を有するように、又は両電荷をこの特定方位に安定化させる永久外部電界によって設計されている。従って、分子をその最初の方位から外すには大きい電界を必要とする。一旦、ある特定方位に切り替えられると、その分子は、切り替えられるまで、その方位に留まることになる。
【０１１９】
逆の電界が印加されると（例６）、両電荷は、逆の外部電界の方向に再配列する傾向がある。分子の上側部分の正電荷は、非結合電子、あるいはπ電子、あるいはπ電子及び非結合電子の非局在化によって分子の側部から分子の中央部分（トリアリールメタンの位置）へ移動する。同様に、負に荷電している分子の下側部分は、Ｃ−Ｃ結合の回転により外部電界へ接近する傾向がある。分子設計の重要な要素は、ＣＯ_２ ⁻と、分子の下側部分（負に荷電した部分）が完全に１８０°反転まで回転するのを妨げるＹ基との間に立体的且つ静的斥力があることである。代わりに、その回転は、下側部分と上側部分にかかる大きい基の立体相互作用によって最初の方位からほぼ９０°の角度で止められる。さらに、この９０°方位は、Ｃ−Ｏ結合の形成及び電荷の再結合によって安定化される。この過程において、トリアリールメタンの位置に四面体炭素（アイソレーター）が形成される。分子の共役が破壊され、ＨＯＭＯ及びＬＵＭＯは、もはや分子の上側部分全体にわたって非局在化していない。これは、電子によって占有された容積を縮小させる効果があり、それによってＨＯＭＯ−ＬＵＭＯギャップが増大する。この過程において、青方偏移した色あるいは透明状態が生じることになる。
【０１２０】
有色のインク及び染料分子の場合、分子の一端と中央位置との間の正電荷の移動の制限は極めて重要である。別の重要な因子は、固定子（分子の上側部分）から光学的に意味のある角度（名目上１０〜１７０°）だけ隔てられた２つの状態間で、回転子（分子の下側部分）を切り替える能力である。分子内電荷の分離が最大距離に達すると、分子の最も上側の部分が完全な共役状態となる。分子のπ電子、あるいはπ電子及び非結合電子は、その最高被占分子軌道（ＨＯＭＯ）及び最低空分子軌道（ＬＵＭＯ）を介して、最も上側の領域全体にわたって非局在化する。その効果は、箱内の量子力学的粒子に対するそれと同一であり、その箱が分子全体の大きさであるとき、即ち軌道が非局在化されるとき、ＨＯＭＯ及びＬＵＭＯ間のギャップは比較的小さい。この場合、分子のＨＯＭＯ−ＬＵＭＯギャップは、所望の色のインクあるいは染料をもたらすように設計される。全平行構造に関するＨＯＭＯ−ＬＵＭＯギャップは、種々の化学基（Ｊ_１、Ｊ_２、Ｊ_３、Ｊ_４及びＷ）を、当該分子の異なる芳香環上に置換させることにより調整することができる。回転子及び固定子に結合させる化学置換基（Ｊ_１、Ｊ_２、Ｊ_３、Ｊ_４及びＷ）の性質に応じて、回転子（分子の下側部分）が固定子（分子の上側部分）に関して１０〜１７０°だけ回転する場合には、増加したＨＯＭＯ−ＬＵＭＯギャップは、全平行構造の色に関して青方偏移した色に対応するであろう。偏移が十分に大きい場合に、新しいＨＯＭＯ−ＬＵＭＯギャップが十分に大きいなら、その分子は透明になる。従って、その分子は２つの色の間で、又はある色から透明状態に切替え可能である。
【０１２１】
例５及び６は、外部印加された電界の影響下での代表的な切替可能型分子の２つの異なった状態を示している。この特定の種類の分子に関しては、例えばラングミュア−ブロジェット技術、気相成長法、あるいは電気化学的付着法を利用して、分子の方位軸が分子を切り替えるのに使用される電極の面に垂直になるように十分厚い分子膜を成長させている。他の付着技術は、分子をモノマー／オリゴマーあるいは溶媒系溶液として懸濁させ、それを基材上へ厚膜コーティング（例えば、リバースロール）、あるいはスピンコーティングし、その後、分子を配列させる電界にかけながら、その被覆物を重合（例えば、ＵＶ照射によって）あるいは乾燥させるものである。電極表面には、例えばインジウム−酸化スズのような透明導体を用いることができ、その膜は、分子軸が電極の面に平行になるよう成長させる。分子は、固体あるいは液晶を形成し、大きい固定子基は分子間相互作用あるいは支持構造への直接結合によって定位置に固定されるが、回転子は分子の格子内部で十分移動できるほど小さい。
【０１２２】
モデル（３）：分子の折畳みあるいは引伸ばしを介する電界誘導性バンドギャップ変化
図７は、本モデルの概略図であり、それは、分子の折畳みあるいは引伸ばしを介する拡張共役の変化によって引き起こされる電界誘導性バンドギャップの変化を伴うものである。図７に示すように、分子７３０は、３つの部分７３２、７３４、及び７３６からなる。分子７３０は、分子だの大部分にわたる拡張共役のため比較的小さいバンドギャップを示す。電界の印加によって、中央部分７３４の辺りでの分子の折畳みに起因して、分子７３０における共役の破壊が起こり、その結果分子の大部分にわたる非拡張共役のため、バンドギャップがより大きい状態になる。電界の反転によって分子７３０は伸長し、分子７３０はその元の状態に戻る。分子７３０の中央部分７３４を伸長及び弛緩させることは同じ効果を有する。
【０１２３】
本モデルでは、以下の要件が満たされなければならない。
（ａ）当該分子は、少なくとも２つの部分を有していなければならない。
（ｂ）いくつかの部分が、ＨＯＭＯ、ＬＵＭＯ、及び隣接軌道に含まれる非結合電子、あるいはπ電子、あるいはπ電子及び非結合電子を有していなければならない。
（ｃ）当該分子は、一方の側にあるアクセプター基と他方の側にあるドナー基に関して、対称であっても、非対称であってもよい。
（ｄ）分子の少なくとも２つの部分は、水素結合、ファンデルワールス力、クーロン引力あるいは金属錯体形成のような分子内又は分子間力によって折畳みあるいは伸長の両状態を安定化させるのに役立つ幾つかの官能基を有している。
（ｅ）分子の折畳みあるいは引伸ばしの状態は、電界によってアドレス指定できなければならない。
（ｆ）少なくとも１つの状態（おそらく、完全に伸長した状態）において、分子の非結合電子、あるいはπ電子、あるいはπ電子及び非結合電子が、十分非局在化しており、且つ分子のπ及びｐ電子が、他の状態においては、局在化しているか又は部分的にのみ非局在化している。
（ｇ）分子のバンドギャップが、印加された外部電界によって分子が折畳まれたり、あるいは引き伸ばされる間の、分子中の非結合電子、あるいはπ電子、あるいはπ電子及び非結合電子の非局在化の程度に依存して変化し、この種の変化もまた分子の導電率に影響する。
（ｈ）この特性によって、これらの種類の分子が、光あるいは電気スイッチ、ゲート、記憶装置あるいはディスプレイ用途にも適用することができる。
【０１２４】
分子の折畳みあるいは伸長を介する電界誘導性ギャップ変化の一例を以下（例７）に示す。
【０１２５】
【化９】

【０１２６】
ここで、Ｒ_１及びＲ_２は、分子内に組み込まれているスペーシング基を表す。それらのスペーシング基は、水素、炭化水素（飽和あるいは不飽和のいずれか）あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１２７】
文字Ｊ_１、Ｊ_２、Ｊ_３、Ｊ_４及びＪ_５は、分子に組み込まれている調整基を表す。これらの調整基（例えば、ＯＨ、ＮＨＲ、ＣＯＯＨ、ＣＮ、ニトロ等）の機能は、適切な機能的効果（例えば、誘導性効果及び共鳴効果の両方）及び／又は立体効果をもたらすことである。機能的効果とは、分子のバンドギャップ（ΔＥ_{ＨＯＭＯ／ＬＵＭＯ}）を調整し、分子の所望の光学的特性だけではなくて、電子的特性も得ることである。立体効果とは、立体障害、分子間あるいは分子内相互作用力（例えば、水素結合、クーロン相互作用、ファンデルワールス力）を介して分子配座を調整して、分子の向きの双安定性あるいは多重安定性をもたらすことである。それらは又、スペーシング基としても用いることができる。それらは、水素、ヘテロ原子（例えば、Ｎ、Ｏ、Ｓ、Ｐ、Ｂ、Ｆ、Ｃｌ、Ｂｒ及びＩ）、前記ヘテロ原子のうちの少なくとも１つを有する官能基、炭化水素（飽和あるいは不飽和のいずれか）、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１２８】
文字Ｙ及びＺは、分子間又は分子内水素結合を形成することになる官能基である。それらの官能基は、ＳＨ、ＯＨ、アミン、炭化水素、あるいは置換炭化水素、のうちの任意のものとすることができる。
【０１２９】
図面の上側の分子は、共役が分子の種々の部分に局在化することに起因して、より大きなバンドギャップを有するが、下側の分子は、分子の大部分にわたる拡張共役に起因して、より小さいバンドギャップを有する。
【０１３０】
光スイッチ（マイクロメートルあるいはナノメートル）を形成するために本明細書にて開示され、特許請求される技術は、ディスプレイ、電子ブック、書換え可能媒体、電気的に調整可能な光学レンズ、窓及びミラーのための電気制御による着色、数多くの入力チャネルのうちの１つから数多くの出力チャネルのうちの１つに信号を送るための光クロスバースイッチなどを製造するために用いることができる。
【産業上の利用可能性】
【０１３１】
本明細書に開示される電界切替え可能分子は、種々の視認ディスプレイにおいてだけではなくて、マイクロスケール、さらにはナノスケールの構成要素から構成される光学デバイスにおいて用途が見出されるものと期待される。
【図面の簡単な説明】
【０１３２】
【図１】本発明に従って用いるための２色（例えば白黒）ディスプレイ画面構成の概略図（斜視透視図）
【図１ａ】図１に示すディスプレイ画面の着色剤層要素の詳細図
【図２】本発明に従って用いるためのフルカラーディスプレイ画面構成の概略図（斜視透視図）
【図３】本発明に従って用いるための２色ディスプレイ画面構成の走査アドレス指定の実施形態の概略図
【図４】分子配座の変化を介する電界誘導バンドギャップ変化を示す概略モデル（回転子／固定子方式モデル）
【図５ａ】双極子を有する中央回転子部及び２つの端部固定子部からなる分子
【図５ｂ】回転子及び固定子が全て同一面上にある平坦な状態を示している図５ａ記載の分子の概略図（斜視図）
【図５ｃ】回転子が固定子に対して９０°回転している回転状態を示している図５ａ記載の分子の概略図（斜視図）
【図６ａ】バンド局在化の増減を伴う電荷の分離あるいは再結合を介する拡張共役の変化によって引き起こされる電界誘導バンドギャップ変化を示す概略モデル
【図６ｂ】電荷の分離あるいは再結合、及びπ結合の破壊あるいは形成を介する拡張共役の変化によって引き起こされる電界誘導バンドギャップ変化を示す概略モデル
【図７】分子折り畳みあるいは伸長を介する電界誘導バンドギャップ変化を示す概略モデル【Technical field】
[0001]
The present invention relates generally to optical devices whose functional length scale is in the order of nanometers, and more particularly to a class of molecules that provide optical switching. Both micrometer (μm) and nanometer (nm) scale electronic devices can be constructed in accordance with the teachings herein.
[Background]
[0002]
The field of molecular electronics is at an early stage. To date, there are two compelling arguments for what has been published in the technical literature for molecules such as electronic switches. C. P. Science by Collier et al., Vol. 285, pp. 391-394 (July 16, 1999) and C.I. P. Science by Collier et al., Vol. 289, pp. See 1172-1175 (August 18, 2000). However, there are a lot of thoughts and interests within the scientific community surrounding this topic. In published studies, a molecule called rotaxane or catenane was trapped between two metal electrodes and switched from the ON state to the OFF state by applying a positive bias across the molecule. For rotaxane and catenane, the resistivity was different from about 100 and 5 in the ON and OFF states, respectively.
[0003]
The main problem with rotaxanes was that it is an irreversible switch. It can only be switched once. Thus, it can be used for programmable read-only memory (PROM), but not in RAM (Random Access Memory) -like devices or in reconfigurable systems such as fault tolerant communications and logical networks. Furthermore, rotaxanes must undergo oxidation and / or reduction reactions before switching. This requires a considerable amount of energy consumption to switch. In addition, the large and complex properties of rotaxane molecules and homologous compounds can slow the switching time of the molecules. The main problems with catenans are low ON-OFF ratio and slow switching time.
[0004]
Currently there are a wide variety of known chromogenic materials that provide optical switching in thin film form. These materials and their uses have recently been described in C.I. B. Greenberg,Thin Solid FilmsVol. 251 pp. 81-93 (1994), and R.A. J. et al. Mortimer,Chemical Society ReviewsVol. 26, pp. 147-156 (1997). These materials currently include active darkening of sunglasses, active darkening of windows for intelligent lights and building thermal management, and head-up displays and eyeglass displays on the inner surface of automobile or aircraft windshields. Have been studied for a variety of applications, including various types of optical displays.
[0005]
Although they have been very promising for a long time, few photon gating devices formed from existing types of electrochromic materials. This is because most of them pass H through certain liquid or solid electrolytes.⁺, Li⁺Or Na⁺This is because an oxidation-reduction reaction involving the transport of ions as described above is required. Since any device that requires ion transport is slow, finding a suitable electrolyte is a major challenge. In addition, such reactions are extremely sensitive to ambient contaminants such as oxygen or other chemical species, and thus the deterioration of the chromogenic electrode is the main weakness.
[0006]
In fact, for photon switching applications such as crossbar switch routers for optical communication networks, companies are forced to use a variety of techniques, as described below, because there are no suitable color-forming materials. (A) Convert the optical signal to an electronic signal, perform the switching operation, and then return to the optical signal before sending it to the optical fiber (although this is the most frequently used solution at the present time) Very inefficient and difficult to operate electronic circuits without delaying the data rate of the optical system), (b) optical data packets using a movable mirror array formed by microelectromechanical (MEM) processing (Which has the disadvantage of requiring extremely high tolerances for the device and very expensive), (c) using inkjet technology to push bubbles into the chamber and reflect the light beam (This technique also needs to be precisely manufactured and has a slow switching time).
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0007]
Thus, chemical oxidation and / or reduction can be avoided, the mode can be switched from the first state to the second state at a reasonable rate and is reversible to enable real-time or video rate display applications. There is a need for molecular systems that can be used in a variety of optical devices.
[Means for Solving the Problems]
[0008]
According to the present invention, a molecular system for optical switching is provided. In the molecular system, the field induced bandgap change occurs through one of the following mechanisms:
(1) Molecular conformational change or isomerization,
(2) Change of extended conjugation via chemical bond change that changes the band gap,
Or
(3) Molecular folding or stretching.
[0009]
The change in extended conjugation through chemical bond changes that change the band gap can be achieved in one of the following ways.
(A) Separation or recombination of charges accompanying increase or decrease of band localization
Or
(B) Extended conjugation change through charge separation or recombination and π bond breakage or formation
[0010]
The present invention can form, for example, displays, electronic books, rewritable media, electronic lenses, electrically controlled coloring for windows and mirrors, optical crossbar switches for optical fiber communications, etc., by easily combining them. Provide an optical switch. Such applications are discussed elsewhere and are not closely related to the present invention, except where the optical switch of the present invention is used to construct devices for such applications.
[0011]
The present invention provides several types of new switching mechanisms: (1) electric field induced rotation of the rotatable part (rotor) of at least one molecule, which changes the band gap of the molecule, and (2) changes the band gap. It introduces field-induced charge separation or recombination of molecules through chemical bond changes, and (3) field-induced band gap changes through molecular folding or stretching. These devices are generally considered to be electric field devices and should therefore be distinguished from earlier embodiments (described in the related patent applications and patents mentioned above) dealing with electrochemical devices. is there.
[0012]
The present invention also introduces the ability to use molecules for optical switches, where the molecules change color when changing states. This property can be used in a wide variety of display devices, or any other application made possible by materials that can change color or change from transparent to colored.
【The invention's effect】
[0013]
Thus, the molecule is not oxidized or reduced in switching the switch. In addition, the movable part of the molecule is extremely small, and therefore the switching time is expected to be extremely fast. Also, the molecules are much simpler than rotaxanes, catenanes, and homologous compounds, and thus can be produced more easily and cheaply.
Means for Carrying Out the Invention
[0014]
A . Definition
The term “self-organizing” as used herein refers to a system that naturally selects certain geometric patterns depending on the characteristics of the system components. By selecting the configuration of the system, the energy is at least minimized.
[0015]
The term “one-time configurable” means that the switch can change its state only once through an irreversible process such as an oxidation or reduction reaction. Such a switch can, for example, form the basis of a programmable read only memory (PROM).
[0016]
The term “reconfigurable” means that the switch can change its state many times through a reversible process such as oxidation or reduction. In other words, the switch can be opened and closed many times, such as a memory bit of a random access memory (RAM) or a color pixel of a display.
[0017]
The term “bistable” when applied to a molecule means a molecule that has two relatively low energy states (minimum) separated by an energy (or activation) barrier. The molecule can be irreversibly switched from one state to another (configurable only once) or reversibly switched from one state to another (reconfigurable). The term “multistable” refers to molecules having more than two low energy states, ie, local minima.
[0018]
The micron-scale size means a size ranging from 1 μm to several μm.
[0019]
The submicron scale means a size in the range from 0.05 μm to 1 μm.
[0020]
The size on the nanometer scale means a size in a range from 0.1 nm to 50 nm (0.05 μm).
[0021]
Micron-scale and sub-micron-scale wires are rod-shaped having a width or diameter of 0.05 μm to 10 μm, a height ranging from several tens of nm to 1 μm, and a length of several μm or more. A ribbon-like conductor or semiconductor is meant.
[0022]
“HOMO” is a general chemical abbreviation for representing “highest occupied molecular orbital”, and “LUMO” is a general chemical abbreviation for representing “lowest unoccupied molecular orbital”. HOMO and LUMO lead to electron conduction in the molecule, and the energy difference between HOMO and LUMO and other energetically close molecular orbitals contributes to the color of the molecule.
[0023]
Optical switches involve, in the context of the present invention, changes in the electromagnetic properties of molecules within and outside the human visible range, for example, ranging from far infrared (IR) to deep ultraviolet (UV). Optical switching includes property changes such as absorption, reflection, refraction, diffraction and diffuse scattering of electromagnetic radiation.
[0024]
The term “transparent” means that light defined in the visible spectrum, other than the region where spectral components are absorbed by the colorant, is not optically disturbed or altered by light passing through the colorant. For example, if a molecular colorant does not absorb light in the visible spectrum, the colorant will appear to have a clear, colorless transparency.
[0025]
The term “total environmental lighting visibility” is defined herein as visibility under any environmental lighting conditions to which the eye is sensitively responsive.
[0026]
B. Light switch
Optical switches are described in further detail in co-pending US patent application Ser. No. 09 / 981,166, dated Oct. 16, 2001. A general example resulting from that patent application is shown in FIG. 1 herein, which shows a display screen 100 incorporating at least one colorant layer 101. The colorant layer 101 consists of a pixel array using dye or pigment molecules that are switchable by an electric field and are reconfigurable according to the present invention, described in more detail below and generally referred to as “molecular colorants”. Each dye or pigment molecule can be switched between an image forming color (eg black) and a transparent state by an electric field, or between two different colors (eg red and green).
[0027]
Referring briefly to FIG. 1a, the colorant layer 101 is an addressable pixel array formed from bistable molecules in which a selected set of molecules are aligned so as to correlate with a pixel. It is. The colorant layer 101 is a thin layer that is coated on a background substrate 103 having the intended background color (eg, white) of the display. The substrate 103 can be composed of, for example, a high dielectric pigment (eg, titania) containing polymer binder that minimizes the voltage drop across the layer and provides good whiteness and opacity. Therefore, the layered arrangement consisting of the combination of the colorant layer 101 and the substrate 103 is completely similar to the ink layer on paper. In the blank state, ie, the erased state, each molecule is switched to its transparent orientation and the “ink layer” is not visible. The background (eg, white pixels) appears over the pixel area where the colorant layer 101 molecules are switched to a transparent orientation. In order to provide adequate protection, a clear, clear layer, for example made of clear plastic or glass, is provided on the colorant-background sandwich structure. The transparent layer 105 has a transparent electrode array 107 for driving pixel columns or rows attached to it and disposed on top of the colorant layer 101. The background substrate 103 has complementary electrode arrays 109 attached to it to drive pixel columns or rows (in a layered array of electrode arrays 107, 109 for matrix addressing of individual pixels and writing by electric fields). Those skilled in the art will appreciate that certain embodiments may be modified in accordance with conventional electrical engineering practices). Optionally, the pixels are superimposed on each other by employing thin film transistor (TFT) driver technology as is known in the art.
[0028]
The display 100 enables the same contrast and color as a hard copy print. Molecular colorants are ideal because they are extremely small in size and mass, and resolution and colorant switching times become limited only by the field writing electrodes and circuitry. Like the ink, the colorant layer 101 can have sufficient density in sub-micron to micron level thin layers, potentially reducing the field voltage required to switch the colorant between logic states. As a result, a low-cost driving circuit can be used.
[0029]
Reconfigurable bistable molecules suitable for use in such displays are disclosed below and claimed herein. In general, these molecules have optical properties (eg, color) that depend on the degree of conjugation of π orbital electrons. The optical properties of the molecule, including color or transparency, vary with the polarity of the electric field applied to the molecule and remain chromatically stable even when no electric field is applied. By breaking the continuity of conjugation across a molecule, the molecule can be changed from one optical state to another, for example from colored to transparent. When applying or changing an external electric field, this destruction can be physically caused by rotating certain parts of the dye or pigment molecule relative to other parts or otherwise distorting it. Electric dipoles that can be incorporated into the colorant.
[0030]
The colorant layer 101 is preferably a homogeneous layer made of molecules that are colored in a strongly conjugated direction (for example, black, cyan, magenta or yellow) and transparent in a weakly conjugated direction. By making the adjacent background base material 103 white, the colorant layer 101 can generate high-contrast black and white and color images. The colorant layer 101 can be composed of a single electric field switchable dye or pigment, or can be composed of a mixture of various switchable dyes or pigments that collectively produce a composite color (eg, black). Can do. By using molecular colorants, the resolution of the generated image is limited only by the resolution of the electric field generated by the electrode arrays 107,109. Molecular colorants also have almost instantaneous switching speeds and are useful for fast scanning requirements (as described later with respect to FIG. 3). In certain cases, molecular colorants can be included in the polymer layer. Polymers for producing such coatings are well known and include, for example, acrylates, urethanes, and the like. Alternatively, the colorant layer 101 can be self-organized.
[0031]
In one embodiment, the colorant layer 101 is provided as an alternative to a matrix-addressed liquid crystal flat panel display. As is well known in the case of such displays, each pixel is addressed by a matrix of positioned electrode arrays, eg, 107 and 109 rows and columns. The positioned electrode arrays 107, 109 are made up of conventional crossbar electrodes 111, 113 that sandwich a colorant layer 101 and form a grid of overlapping pixels, where each pixel has an overlapping electrode. Addressed in position. The crossbar electrodes 111 and 113 are formed of electrode lines arranged in electrode rows and electrode columns and spaced apart in parallel. The row electrodes and the column electrodes are divided on opposite sides of the colorant layer 101. Preferably, the first set of transparent crossbar electrodes 107 (201 and 203 in FIG. 2 described in detail later) deposit indium tin oxide (ITO) in a thin film on a transparent substrate (eg, glass). Formed by. These row addressable pixel crossbar electrodes 107 are formed in the ITO layer using conventional thin film patterning and etching techniques. The colorant layer 101 and the background substrate 103 are sequentially coated or disposed on the transparent electrode layer using conventional thin film technology (eg, vapor deposition) or thick film technology (eg, silk screen, spin coating, etc.). The Still other coating techniques include Langmuir-Blodget deposition and self-assembled monolayers. The column addressable pixel crossbar electrodes 109 (202, 204 in FIG. 2) are preferably configured in a similar manner to the row electrodes 107. The column addressable pixel crossbar electrode 109 can optionally be constructed on a separate substrate, which is subsequently deposited with the white coating using conventional techniques.
[0032]
The displays 100, 200 provide contrast, color, viewing angle, and full ambient illumination visibility like printed on paper by eliminating the polarizing layer required in the case of known liquid crystal colorants. Further, by using the display, power consumption can be remarkably reduced. While liquid crystals require a holding electric field even in the case of a still image, the molecules of the colorant layer 101 of the present invention may be kept in a state where there is no electric field when bistable molecules are used. it can. Thus, the bistable colorant layer 101 of the present invention only requires an electric field for a pixel when it is changed. Improvements in power and image quality can improve battery life and display readability under wider viewing and lighting conditions for devices (eg, watches, calculators, cell phones or other portable electronic devices), television monitors and computer displays. Will bring significant benefits. Furthermore, for color displays with low resolution, the colorant layer can be composed of mosaic-like colored pixels using a bi-stable colored molecular array of various colors.
[0033]
Since each colorant molecule in the colorant layer 101 is transparent outside the colorant absorption band, a number of colorant layers are overlaid and individually addressed to provide a higher resolution than that currently available on the market. A color display can be manufactured. FIG. 2 is a schematic diagram of the second embodiment. A high-resolution, full-color matrix-addressable display screen 200 comprises transparent electrodes forming alternating layers, ie, row electrodes 201, 203 and column electrodes 202, 204, and a plurality of colorant layers each having a molecular array of different colors 205, 207, and 209. Since each pixel in each colorant layer can be colored or transparent, the color of a given pixel can be any of the colored layers (eg cyan, magenta, yellow, black) at the maximum address resolution of the display Or a combination of these. If all colorant layers 205, 207, 209 are transparent for a pixel, the pixel exhibits a background substrate 103 (eg white). Such a display has the same pixel density but offers the advantage that it has a resolution three times higher than current matrix LCD devices with a single layer of mosaic color. Details of the manufacture of the display are described in the above-mentioned co-pending patent application.
[0034]
The color to be set for each pixel is addressed by applying a voltage between the electrodes immediately adjacent to the selected colored layer. For example, assuming that yellow is the uppermost colorant layer 205, magenta is the next colorant layer 207, and cyan is the third colorant layer 209, the pixels in the yellow layer have row electrodes 201. And magenta are addressed via column electrode 202 and row electrode 203, and cyan is addressed via row electrode 203 and column electrode 204. Since each colorant molecule has a stable color even when no electric field is applied, this simple common electrode addressing scheme is possible.
[0035]
FIG. 3 shows a third embodiment that uses scan addressing rather than matrix addressing. Matrix addressed displays currently have limited resolution based on the number of address lines and spacing that are patterned on a relatively large two-dimensional display surface, each connecting a pixel row or column to the outer edge of the display area. Is done. In this third embodiment, the bistable molecular colorant layer 101 and background substrate 103 layer combination is combined with a scan electrode array printhead in addition to the same readability as the first two embodiments above, A scan electrode display device 300 is provided that has the advantage of resolution of commercial publications. The scanning electrode array and the driving electronic circuit are common to the electrostatic printer, and its configuration and interface are well known. Basically, recalling that a bistable molecular switch does not require a holding field, the scan electrode array display device 300 changes the displayed image by printing one pixel row at a time. Accordingly, the scan electrode array display device 300 can alternate between odd and even electrode address lines along both sides of the array, and can include multiple address layers with passing array connections, The advantage of being able to stagger multiple arrays that overlap to balance during a scan results in a much greater resolution. The colorant layer 101 is similarly patterned with a color mosaic, and an extremely high resolution scanning color display can be manufactured.
[0036]
More specifically, the third embodiment shown in FIG. 3 comprises a display screen 302, a scan electrode array 304, and an array translation mechanism 301 for accurately moving the electrode array from end to end of the screen surface. ing. The display screen 302 is similarly composed of a background substrate 103, a transparent show-through layer 105, and at least one bistable molecular colorant layer 101. The colorant layer 101 includes a homogeneous monochromatic colorant (eg, black) or a color mosaic, as previously described herein. The scanning electrode array 304 comprises a linear electrode array that is in contact with or substantially in contact with the background substrate 103 or an electrode array that is equally staggered. Staggered electrode arrays can be used, for example, to minimize electric field crosstalk between the electrodes if they are adjacent and to increase the resolution of the display.
[0037]
Each electrode is sized, positioned, and electrically addressed, and in operation, an arrow labeled “E” across the colorant layer 101 at a given pixel location along the pixel column. To provide an appropriate electric field represented by The electric field E can be directed perpendicular to or parallel to the colorant layer 101 surface, depending on the color switching axis of the colorant molecules. A vertical electric field can be generated by placing a common electrode (eg, an ITO layer) on the opposite coating surface of the electrode array. The electrode array can also be configured to generate a fringe electric field. A parallel fringe field can be generated by placing a common electrode adjacent to and parallel to the array. A vertical fringing electric field can be generated by placing symmetrical, spaced parallel common electrodes in the vicinity of the electrode array (s). The voltage is strong enough for the dominant electric field lines formed just below the array 304 to switch the colorant molecule (s) to be addressed, and the divided return electric field lines Adjusted to not. More information regarding alternative embodiments and scanning mechanisms is discussed in the above-mentioned co-pending patent application.
[0038]
C. The present invention
In accordance with the present invention, for the colorant layer 101, a molecule is provided that clearly exhibits one of several new types of switching. In other words, the present invention introduces several new types of switching mechanisms that are distinct from the prior art.
(1) Electric field (E field) induced rotation of at least one rotatable part (rotor) of the molecule that changes the band gap of the molecule
(2) Electric field induced molecular charge separation or recombination via chemical bond changes that change the band gap
(3) Band gap change induced by electric field through molecular folding or stretching
Thus, in contrast to prior art approaches, color switching occurs as a result of electric field induced intramolecular changes rather than diffusion or oxidation / reduction reactions. In addition, since the movable part of the molecule is extremely small, the switching time is expected to be very fast. Furthermore, the molecules are much simpler than rotaxanes, catenanes and homologous compounds and are therefore easy to manufacture and low cost.
[0039]
The following are examples of model molecules and a brief description of their function.
(1) Electric field induced bandgap change via a change in molecular conformation (rotor / stator model)-FIGS. 4 and 5a-5c
(2a) Field-induced bandgap changes caused by charge conjugation with increasing or decreasing band localization or changes in extended conjugation via recombination-FIG. 6a
(2b) Field-induced bandgap change caused by extended conjugation change through charge separation or recombination and π bond breakage or formation-FIG. 6b
(3) Electric field induced bandgap change through molecular folding or elongation-FIG.
[0040]
Hereinafter, each model will be described using an auxiliary example. However, the disclosed examples should not be construed as limiting the invention to the particular molecular system illustrated, but rather as merely illustrative of the switching mechanism described above.
[0041]
Model (1): Electric field induced bandgap change via change in molecular conformation (rotor / stator model)
FIG. 4 is a schematic diagram of this model with electric field induced band gap changes (rotor / stator model) via changes in molecular conformation. As shown in FIG. 4, the molecule 430 includes a rotor part 432 and a stator part 434. The rotor unit 432 is rotated by the applied electric field. In the state shown on the left side of the figure, there is an extended conjugation throughout the molecule, resulting in a relatively small bandgap, thereby absorbing longer wavelength (redshifted) light. In the other state of rotation of the rotor shown on the right side of the figure, the extended conjugate is destroyed, resulting in a relatively large bandgap, thereby causing shorter wavelength (blue-shifted) light. Absorbs. 5a to 5c show another preferred embodiment of the model 1. These latter figures are described below in connection with examples 1 and 2 of this model 1.
[0042]
In this model, the following requirements must be met:
(A) The molecule must have at least one rotor part and one stator part.
(B) In some states of the molecule, delocalized HOMO and / or LUMO (π state and / or non-bonded orbitals) extending across the entire molecule (rotor (s) and stator (s)). Must exist, otherwise the trajectory is localized on the rotor and stator.
(C) The connection unit between the rotor and the stator is (1) non-bonded electrons (p or other electrons), or (2) π electrons, or (3) π electrons and non-bonded electrons (single or plural). Can be one σ bond having at least one atom.
(D) Non-bonded electrons, or π electrons, or π electrons and non-bonded electrons (single or plural) of the rotor (single or plural) and the rotor (single or plural) while the rotor rotates during activation by an electric field. ) Can be localized or delocalized depending on the conformation of the molecule.
(E) The molecular conformation (s) can be electric field dependent or bistable.
(F) The bistable state or states are achieved by intramolecular or intermolecular forces such as hydrogen bonds, Coulomb forces, van der Waals forces, metal ion complex mutual stabilization or dipole mutual stabilization. Can do.
(G) The band gap of the molecule varies depending on the degree of delocalization of non-bonded electrons, π electrons, or π electrons and non-bonded electrons (single or plural). This will control the optical properties (eg color and / or refractive index) of the molecule.
[0043]
The following are two examples of this model (Examples 1 and 2).
[0044]
The novel bimodal molecules of the present invention are active optical devices that can be switched by an external electric field. Preferably, the colorant molecule is bistable. The general concept is that it has a large dipole moment (see Examples 1 and 2) and a rotatable intermediate part (rotation) that connects the other two parts (stator) 434 of the molecule 430 that is immobilized. (Child) 432 is designed in the molecule. Under the influence of the applied electric field, the vector dipole moment of the rotor 432 will attempt to align parallel to the direction of the external electric field. However, the molecule 430 stabilizes the rotor 432 in a particular orientation with respect to the stator 434, such that there are intermolecular and / or intramolecular forces such as hydrogen bonds, dipole-dipole interactions and steric repulsion. Designed to. Therefore, a large electric field is required to rotate the rotor 432 with respect to the stator 434 out of its initial orientation.
[0045]
Once switched to a particular orientation, the molecule 430 will remain in that orientation until it is switched to a different orientation or reconfigured. However, an important element of molecular design is the presence of steric repulsion or obstacles that prevent the rotor 432 from rotating until it is fully rotated 180 °. Instead, the rotation is stopped at an optically effective angle, typically 10 ° -170 ° from the initial orientation, by large group steric interactions on the rotor 432 and / or the stator 434. For illustration purposes, this angle is shown as 90 ° in this application. Furthermore, this switching orientation is stabilized by different sets of intermolecular and / or intramolecular hydrogen bonds or dipole interactions, and thus remains in place even after the applied electric field is released. For bistable or multistable colorant molecules, this ability to keep the rotor 432 between two states that are separated from the stator by an optically effective angle is extremely important.
[0046]
The above method can be generalized and the colorant molecules can be designed to provide several switching steps so that a multi-state (eg multi-color) system can be formed by multiple states (3 or more). With such molecules, the optical properties of the colorant layer are continuously adjusted as the electric field is increased or decreased, or instantaneously from one state to another by applying a pulsed electric field. Will be changed.
[0047]
Furthermore, colorant molecules can be designed to include cases where there is no or low activation barrier due to fast but volatile switching. In this last situation, bistability is not necessary and the molecule is switched to a certain state by the electric field and relaxed to return to its original state upon removal of the electric field (“bimodality”). In practice, these forms of bimodal colorant molecules are “self-erasing”. In contrast, in the case of bistable colorant molecules, the colorant molecules remain in that state even when the electric field is removed (non-volatile switch), in which case there is an activation barrier, so the molecule It is necessary to apply a reverse electric field to switch back to the previous state.
[0048]
When the rotor 432 and the stator 434 are all in the same plane, the molecule is said to be “stronger conjugated”. Thus, the unbonded electrons, or π electrons, or π electrons and unbonded electrons of the colorant molecule span most of the molecule 430 via its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Delocalized. This is called the “red shift state” or “optical state I” of the molecule. If the rotor 432 is rotated from conjugation about 90 ° with respect to the stator 434, the conjugation of the molecule 430 is broken and the HOMO and LUMO are localized over a smaller portion of the molecule, Is called. This is the “blue shift state” or “optical state II” of the molecule 430. Thus, the colorant molecule 430 can switch reversibly between two different optical states.
[0049]
In the ideal case, when the rotor 432 and the stator 434 are perfectly coplanar, the molecules are completely conjugated and the rotor 432 is rotated at an angle of 90 ° with respect to the stator 434. One skilled in the art will appreciate that sometimes molecules are not conjugated. However, due to thermal fluctuations, these ideal states are not fully realized, so the molecule is called "stronger conjugated" in the former case and in the latter case Is called “weaker conjugated”. Furthermore, the terms “redshift” or “blueshift” do not mean to represent any relationship to hue, but to describe the electromagnetic energy spectrum direction of the energy shift of the gap between the HOMO and LUMO states. Means to represent.
[0050]
Examples 1 and 2 show two different orientations for switching molecules. Example 1a below shows an example of a first general molecule for this model 1.
[0051]
[Chemical 1]

Con₁-Connection base
Con₂-Connection base
SB-stator B
SA-Stator A
A⁻-Acceptor (electron withdrawing group)
D⁺-Donor (electron donating group)
[0052]
Where the letter A⁻Represents an acceptor group, which is an electron withdrawing group. It can be hydrogen, carboxylic acid or derivatives thereof, sulfuric acid or derivatives thereof, phosphoric acid or derivatives thereof, nitro, nitrile, heteroatoms (eg N, O, S, P, F, Cl, Br), or It can be one of a functional group having at least one of them (for example, OH, SH, NH, etc.), a hydrocarbon (either saturated or unsaturated) or a substituted hydrocarbon.
[0053]
Letter D⁺Represents a donor group, which is an electron donating group. It can be hydrogen, amine, OH, SH, ether, hydrocarbon (either saturated or unsaturated), or substituted hydrocarbon, or at least one heteroatom (eg, B, Si, N, O, S, P, It can be any one of the functional groups having I). Donors are distinguished from acceptors by the fact that they are less electronegative or more electropositive than acceptor groups on the molecule.
[0054]
Character Con₁And Con₂Represents a connection unit between one molecule and another molecule, or between one molecule and a solid substrate (eg, metal electrode, inorganic or organic substrate, etc.). They are hydrogen (utilizing hydrogen bonds), polyvalent heteroatoms (ie C, N, O, S, P etc.), or functional groups containing these heteroatoms (eg NH, PH etc.), It can be a hydrocarbon (either saturated or unsaturated) or any of the substituted hydrocarbons.
[0055]
The letters SA and SB are used here to indicate stator A and stator B. They can be hydrocarbons (either saturated or unsaturated) or substituted hydrocarbons. Typically, these hydrocarbon units contain a conjugated ring that contributes to the extended conjugation of the molecule when in the planar state (redshift state). In those stator units, they are bridging groups G_nAnd / or spacing group R_nCan be included. A bridging group (eg, acetylene, ethylene, amide, imide, imine, azo, etc.) typically connects the stator to the rotor or connects two or more conjugated rings to form the desired chromophore. Used to get. Alternatively, the connector can consist of a single atom bridge, such as an ether bridge with oxygen atoms, or a direct sigma bond between the rotor and stator. Spacing groups (eg, phenyl, isopropyl, t-butyl, etc.) are suitable three-dimensional to allow the molecules to consolidate while providing space for each rotor to rotate over the desired operating range. Used to establish a framework.
[0056]
Example 1b below is an example of a model 1 actual molecule. In Example 1b, the rotor axis of rotation is designed to be approximately perpendicular to the net current carrying axis of the molecule, whereas in Example 2, the axis of rotation is parallel to the azimuth axis of the molecule. ing. These designs allow the molecular membranes and electrodes used to have various structures depending on the desired result.
[0057]
[Chemical 2]

[0058]
Where the letter A⁻Represents an acceptor group, which is an electron withdrawing group. It can be hydrogen, carboxylic acid or derivatives thereof, sulfuric acid or derivatives thereof, phosphoric acid or derivatives thereof, nitro, nitrile, heteroatoms (eg N, O, S, P, F, Cl, Br), or It can be one of a functional group having at least one of them (for example, OH, SH, NH, etc.), a hydrocarbon (either saturated or unsaturated) or a substituted hydrocarbon.
[0059]
Letter D⁺Represents a donor group, which is an electron donating group. It can be hydrogen, amine, OH, SH, ether, hydrocarbon (either saturated or unsaturated), or substituted hydrocarbon, or at least one heteroatom (eg B, Si, N, O, S, P, It can be one of the functional groups having I). Donors are distinguished from acceptors by the fact that they are less electronegative or more electropositive than acceptor groups on the molecule.
[0060]
Character Con₁And Con₂Represents a connection unit between a molecule and another molecule, or between a molecule and a solid substrate (for example, a metal electrode, an inorganic or organic substrate, etc.). They are hydrogen (utilizing hydrogen bonds), polyvalent heteroatoms (ie C, N, O, S, P etc.), or functional groups containing these heteroatoms (eg NH, PH etc.), It can be a hydrocarbon (either saturated or unsaturated) or any of the substituted hydrocarbons.
[0061]
Letter R₁, R₂, R₃Represents a spacing group incorporated into the molecule. The function of these spacer units is to provide an appropriate three-dimensional framework to allow molecules to be dense while providing a space for rotation for each rotor. They can be any of hydrogen, hydrocarbons (either saturated or unsaturated), or substituted hydrocarbons.
[0062]
Letter G₁, G₂, G₃And G₄Is a bridging group. The function of these bridging groups is to connect the stator and rotor or connect two or more conjugated rings to obtain the desired chromophore. They are heteroatoms (eg, N, O, S, P, etc.), or functional groups having at least one of the above heteroatoms (eg, NH or NHNH), hydrocarbons (either saturated or unsaturated) Or any of substituted hydrocarbons. Alternatively, the connector can be constructed by a single atom bridge, such as an ether bridge with oxygen atoms, or a direct sigma bond between the rotor and the stator.
[0063]
In Example 1b above, the vertical dotted line represents another molecule or solid substrate. The direction of the switching electric field is perpendicular to the vertical dotted line. Such a configuration is used for electrical switching. In the case of optical switching, the coupling can be eliminated and the molecule can simply be placed between the two electrodes. They can also simply bind one molecule to another molecule or one molecule to an organic or inorganic solid substrate. Referring to FIG. 5a, the above molecule (Example 1b) is designed so that the internal rotor 432 is perpendicular to the azimuth axis of the entire molecule 430. In this case, the external electric field is applied along the azimuth axis of the molecule 430 as shown, and the electrodes (vertical dashed lines) are oriented perpendicular to the page and perpendicular to the azimuth axis of the molecule 430. By applying an electric field oriented from left to right in the drawing, the rotor 432 as depicted in the upper drawing can be rotated to the position shown in the lower right drawing, and vice versa. In this case, the rotator 432 as depicted in the lower right drawing is not coplanar with the rest of the molecule, so this is the blue-shift optical state of the molecule, while the upper In the figure, this is the red-shift optical state of the molecule because the rotator is coplanar with the rest of the molecule. The structure shown in the lower left drawing represents the rotation transition between the upper drawing (same plane, conjugate) and the lower right drawing (central portion is rotated, non-conjugated).
[0064]
The molecule shown in Example 1b is transparent or blue-shifted. In the conjugated state, the molecule is colored or red-shifted.
[0065]
In the case of the molecule shown in Example 1b, a single monolayer molecular film is grown using, for example, the Langmuir-Blodgett method or a self-assembled monolayer so that the azimuthal axis of the molecule switches the molecule. Be perpendicular to the electrode surface used. The electrodes can be deposited in the manner set forth by Collier et al. Above or as described in the aforementioned related patent applications and issued patents. Other thicker film deposition techniques include vapor deposition, contact or ink jet printing, or silk screen.
[0066]
Example 2a below shows a second generic molecule example for this model 1.
[0067]
[Chemical 3]

Con₁-Connection base
Con₂-Connection base
SB-stator B
SA-Stator A
A⁻-Acceptor (electron withdrawing group)
D⁺-Donor (electron donating group)
[0068]
Where the letter A⁻Represents an acceptor group, which is an electron withdrawing group. It can be hydrogen, carboxylic acid or derivatives thereof, sulfuric acid or derivatives thereof, phosphoric acid or derivatives thereof, nitro, nitrile, heteroatoms (eg N, O, S, P, F, Cl, Br), or It can be one of a functional group having at least one of them (eg, OH, SH, NH, etc.), a hydrocarbon (either saturated or unsaturated), or a substituted hydrocarbon.
[0069]
Letter D⁺Represents a donor group, which is an electron donating group. It can be hydrogen, amine, OH, SH, ether, hydrocarbon (either saturated or unsaturated), or substituted hydrocarbon, or at least one heteroatom (eg, B, Si, I, N, O, S, It can be any one of the functional groups having P). Donors are distinguished from acceptors by the fact that they are less electronegative or more electropositive than acceptor groups on the molecule.
[0070]
Character Con₁And Con₂Represents a connection unit between one molecule and another molecule, or between one molecule and a solid substrate (eg, metal electrode, inorganic or organic substrate, etc.). They can be hydrogen (using hydrogen bonds), polyvalent heteroatoms (ie, C, N, O, S, P, etc.), or functional groups containing these heteroatoms (eg, NH, PH, etc.), carbonization It can be any of hydrogen (either saturated or unsaturated) or substituted hydrocarbons.
[0071]
The letters SA and SB are used here to indicate stator A and stator B. They can be hydrocarbons (either saturated or unsaturated) or substituted hydrocarbons. Typically, these hydrocarbon units contain conjugated rings that contribute to the extended conjugation of the molecule when in the planar state (redshift state). In those stator units, they are bridging groups G_nAnd / or spacing group R_nCan be included. Bridging groups are typically used to connect a stator and a rotor or to connect two or more conjugated rings to obtain the desired chromophore. Alternatively, the connector can consist of a single atom bridge, such as an ether bridge with oxygen atoms, or a direct sigma bond between the rotor and stator. Spacing groups provide a suitable three-dimensional framework to allow molecules to be dense while providing space for each rotor to rotate.
[0072]
Example 2b below is an example of another actual molecule of model 1.
[0073]
[Formula 4]

[0074]
Where the letter A⁻Represents an acceptor group, which is an electron withdrawing group. It can be hydrogen, carboxylic acid or derivatives thereof, sulfuric acid or derivatives thereof, phosphoric acid or derivatives thereof, nitro, nitrile, heteroatoms (eg N, O, S, P, F, Cl, Br), or It can be one of a functional group having at least one of them (eg, OH, SH, NH, etc.), a hydrocarbon (either saturated or unsaturated), or a substituted hydrocarbon.
[0075]
Letter D⁺Represents a donor group, which is an electron donating group. It can be hydrogen, amine, OH, SH, ether, hydrocarbon (either saturated or unsaturated), or substituted hydrocarbon, or at least one heteroatom (eg, B, Si, I, N, O, S, It can be one of the functional groups having P). Donors are distinguished from acceptors by the fact that they are less electronegative or more electropositive than acceptor groups on the molecule.
[0076]
Character Con₁And Con₂Represents a connection unit between one molecule and another molecule, or between one molecule and a solid substrate (eg, metal electrode, inorganic or organic substrate, etc.). They are hydrogen (utilizing hydrogen bonds), polyvalent heteroatoms (ie C, N, O, S, P etc.), or functional groups containing these heteroatoms (eg NH, PH etc.), It can be any of hydrocarbons (either saturated or unsaturated) or substituted hydrocarbons.
[0077]
Letter R₁, R₂And R₃Represents a spacing group incorporated into the molecule. The function of these spacer units is to provide an appropriate three-dimensional framework to allow molecules to be dense while providing a space for rotation for each rotor. They can be any of hydrogen, hydrocarbons (either saturated or unsaturated), or substituted hydrocarbons.
[0078]
Letter G₁, G₂, G₃, G₄, G₅, G₆, G₇And G₈Represents a bridging group. The function of these bridging groups is to connect the stator and rotor or connect two or more conjugated rings to obtain the desired chromophore. They are heteroatoms (eg, C, N, O, S, P, etc.), or functional groups having at least one of the heteroatoms (eg, NH or NHNH), hydrocarbons (saturated or unsaturated) Or any of substituted hydrocarbons. Alternatively, the connector can consist of a single atom bridge, such as an ether bridge with oxygen atoms, or a direct sigma bond between the rotor and stator.
[0079]
Letter J₁And J₂Represents a control group incorporated in the molecule. The function of these tuning groups (eg, OH, NHR, COOH, CN, nitro, etc.) is to provide appropriate functional effects (eg, both inductive and resonant effects) and / or steric effects. The functional effect is the molecular band gap (ΔE_{HOMO / LUMO}) To obtain not only the optical properties of the molecules but also the desired electronic properties. Steric effects include steric hindrance, intermolecular or intramolecular interaction forces (eg, hydrogen bonds, Coulomb interactions, van der Waals forces), or molecular azimuthal bistability. Or provide multiple stability. They are hydrogen, heteroatoms (eg N, O, S, P, B, F, Cl, Br and I), functional groups having at least one of the heteroatoms, hydrocarbons (saturated or unsaturated) Any of hydrocarbons) or substituted hydrocarbons.
[0080]
The molecule (Example 2b) is designed with an internal rotator parallel to the azimuthal axis of the entire molecule. In this case, the external electric field is applied perpendicular to the molecular axis. The electrodes are oriented parallel to the long axis of the molecule and can be oriented on the surface perpendicular or parallel to the plane of the model structure. For example, by applying an electric field whose electric field line is perpendicular to the molecular axis and pointing upward to the upper molecule, the rotor depicted in the figure becomes as shown in the lower molecular drawing, Rotate approximately 90 ° and the edge appears. The reverse is also possible. In this case, the rotator as depicted in the lower drawing is not coplanar with the rest of the molecule, so this is the blue-shifted optical state of the molecule, ie optical state II, while In the upper drawing, the rotator is coplanar with the rest of the molecule, so this is the red-shifted optical state of the molecule, or optical state I (the symbols N, H and O are their normal Has meaning).
[0081]
FIG. 5a is similar to the molecule of Examples 1b and 2b, but is simpler and consists of a central rotor portion 432 and two end stator portions 434. FIG. As in Examples 1b and 2b, the rotor portion 432 is composed of a benzene ring provided with a substituent that becomes a rotor having a dipole. Each of the two stator portions 434 is covalently bonded to the benzene ring via an azo bond, and both portions are made of an aromatic ring.
[0082]
FIG. 5 b is a schematic view (perspective view) showing a flat state in which the rotor 432 and the stator 434 are all on the same plane. In the flat state, the molecule 430 is completely conjugated, clearly shows color (first spectrum or optical state), and is relatively highly conductive. Ring conjugation is illustrated by π-orbital clouds 500a and 500b above and below the face of molecule 430, respectively.
[0083]
FIG. 5c is a schematic view (perspective view) showing the rotated state, with the rotor 432 rotated 90 ° with respect to the stator 434 and the stator still in the same plane. In the rotated state, the conjugation of molecule 430 is broken. As a result, the molecule 430 becomes transparent (second spectrum or optical state) and has a relatively low conductivity.
[0084]
Regarding the molecule of Example 2b, a thin film is formed so that the molecular axis is parallel to the electrode surface. As a result, a film in which a large number of single layers are overlapped is formed. Molecules form solid crystals or liquid crystals, and large stator groups are fixed in place by intermolecular interactions or direct bonds to the support structure, but the rotor is small enough to move within the molecular lattice. . This type of structure can be used to form a field-controlled display, or can be used for other applications as previously described herein.
[0085]
Model (2a): Field-induced band gap change caused by charge conjugation with increasing or decreasing band localization or changes in extended conjugation via recombination
FIG. 6a is a schematic diagram of this model, which involves a field-induced bandgap change caused by a change in extended conjugation via charge separation or recombination with increased or decreased band localization. As shown in FIG. 6 a, the molecule 630 consists of two parts 632 and 634. Molecule 630 exhibits a relatively large band gap with less π delocalization. Application of an electric field causes charge separation within the molecule 630, resulting in sufficient π delocalization and a smaller band gap. Charge recombination causes molecule 630 to return to its original state.
[0086]
In this model, the following requirements must be met:
(A) The molecule has a moderate dielectric constant ε_τAnd must be easily polarized by an external electric field. ε_τIs in the range of 2 to 10, and the polarization electric field is in the range of 0.01 to 10 V / nm.
(B) At least one site of the molecule must have non-bonded electrons, or π electrons, or π electrons and non-bonded electrons that can move throughout the molecule or part thereof.
(C) The molecule can be symmetric or asymmetric.
(D) The inductive dipole (s) of the molecule can be oriented in at least one direction.
(E) Charges are partially or completely separated during field induced polarization.
(F) The state of charge separation or recombination is electric field dependent or bistable, such as covalent bond formation, hydrogen bonding, charge attraction, Coulomb force, metal complex, Lewis acid (base) complex, etc. It can be stabilized by intramolecular or intermolecular forces.
(G) The process of molecular charge separation or recombination may or may not involve the destruction or formation of σ and π bonds.
(H) During the charge separation or recombination process promoted by the electric field, the band gap of the molecule is debonded electrons, or π electrons, or the degree of delocalization of π electrons and nonbonded electrons in the molecule. Varies depending on Both the optical and electrical properties of the molecule change accordingly.
[0087]
An example of a field-induced band gap change (color change) through charge separation or recombination accompanied by bond breakage or bond formation is shown below (Example 3).
[0088]
[Chemical formula 5]

[0089]
Where the letter J₁, J₂, J₃, J₄And J₅Represents a control group incorporated in the molecule. The function of these tuning groups (eg, OH, NHR, COOH, CN, nitro, etc.) is to provide appropriate functional effects (eg, both inductive and resonant effects) and / or steric effects. The functional effect is the molecular band gap (ΔE_{HOMO / LUMO}) To obtain not only the desired optical properties of the molecule, but also the desired electronic properties. Steric effects include steric hindrance, intermolecular or intramolecular interaction forces (eg, hydrogen bonds, Coulomb interactions, van der Waals forces), or molecular azimuthal bistability. Or give multiple stability. They are hydrogen, heteroatoms (eg N, O, S, P, B, F, Cl, Br and I), functional groups having at least one of the heteroatoms, hydrocarbons (saturated or unsaturated) Or any of substituted hydrocarbons.
[0090]
Letter G₁Is a bridging group. The function of the bridging group is to connect two or more conjugated rings to obtain the desired chromophore. The bridging group can be any heteroatom (eg, N, O, S, P, etc.), a functional group having at least one of the heteroatoms (eg, NH), a hydrocarbon or a substituted hydrocarbon. Can be.
[0091]
The letter W is an electron withdrawing group. The function of this group is to coordinate the reaction of the maleic anhydride group of the molecule, which under the influence of an applied external electric field, the molecule is able to smoothly separate or recombine (break or form bonds). Etc.). The electron withdrawing group is a carboxylic acid or a derivative thereof (for example, ester or amide), nitro, nitrile, ketone, aldehyde, sulfone, sulfuric acid or a derivative thereof, heteroatom (for example, F, Cl, etc.) or at least one It can be any of the functional groups having heteroatoms (eg, F, Cl, Br, N, O, S, etc.).
[0092]
An example of an electric field induced band gap change accompanied by formation of a molecule-metal complex or a molecule-Lewis acid complex is shown below (Example 4).
[0093]
[Chemical 6]

[0094]
Where the letter J₁, J₂, J₃, J₄And J₅Represents a tuning group incorporated into the molecule. The function of these tuning groups (eg, OH, NHR, COOH, CN, nitro, etc.) is to provide appropriate functional effects (eg, both inductive and resonant effects) and / or steric effects. The functional effect is the molecular band gap (ΔE_{HOMO / LUMO}) To obtain not only the desired optical properties of the molecule, but also the electronic properties. Steric effects include steric hindrance, intermolecular or intramolecular interaction forces (eg, hydrogen bonds, Coulomb interactions, van der Waals forces), or molecular bistability. Or provide multiple stability. They are hydrogen, heteroatoms (eg N, O, S, P, B, F, Cl, Br and I), functional groups having at least one of the heteroatoms, hydrocarbons (saturated or unsaturated) Or any of substituted hydrocarbons.
[0095]
Symbol G₁Is a bridging group. The function of the bridging group is to connect two or more conjugated rings to obtain the desired chromophore. The bridging group can be any heteroatom (eg, N, O, S, P, etc.), a functional group having at least one of the heteroatoms (eg, NH), a hydrocarbon or a substituted hydrocarbon. Can be.
[0096]
M⁺Is a metal containing a transition metal, or a halogen complex thereof, or H⁺Or other types of Lewis acid (s).
[0097]
Model (2b): Charge separation or recombination, and expansion via π bond breaking or formation Field-induced band gap changes caused by changes in tension conjugate
FIG. 6b is a schematic diagram of the model, which involves a change in the field-induced band gap caused by a change in extended conjugation through charge separation or recombination and π bond breakdown or formation. As shown in FIG. 6b, the molecule 630 'consists of two parts 632' and 634 '. Molecule 630 'exhibits a relatively small band gap. Application of an electric field causes the destruction of π bonds in the molecule 630 ', resulting in a larger band gap. By reversing the electric field, the π bond is recombined between the two portions 632 'and 634' and the molecule 630 'returns to its original state.
[0098]
The requirements that must be met in this model are the same as those listed for model 2 (a).
[0099]
An example of an electric field induced bandgap change caused by a change in extended conjugation via charge separation (breaking of σ bonds and formation of π bonds) is shown below (Example 5).
[0100]
[Chemical 7]

[0101]
Here, the letter Q is used to indicate a connecting unit between two phenyl rings. The connecting unit can be any of S, O, NH, NR, hydrocarbons or substituted hydrocarbons.
[0102]
Character Con₁And Con₂Represents a connection unit between one molecule and another molecule, or between one molecule and a solid substrate (eg, metal electrode, inorganic or organic substrate, etc.). They can be hydrogen (via hydrogen bonding), heteroatoms (ie, N, O, S, P, etc.), or functional groups containing at least one of the heteroatoms (eg, NH, etc.), hydrocarbons (saturated or Any of unsaturated hydrocarbons) or substituted hydrocarbons.
[0103]
Letter R₁And R₂Represents a spacing group incorporated into the molecule. The function of these spacer units is to provide an appropriate three-dimensional framework to allow molecules to be dense while providing a space for rotation for each rotor. They can be any of hydrogen, hydrocarbons (either saturated or unsaturated), or substituted hydrocarbons.
[0104]
Letter J₁, J₂, J₃And J₄Represents a control group incorporated in the molecule. The function of these tuning groups (eg, OH, NHR, COOH, CN, nitro, etc.) is to provide appropriate functional effects (eg, both inductive and resonant effects) and / or steric effects. The functional effect is the molecular band gap (ΔE_{HOMO / LUMO}) To obtain not only the desired optical properties of the molecule but also the electronic properties. The steric effect means that the molecular conformation is adjusted via steric hindrance, intermolecular or intramolecular interaction force (eg, hydrogen bond, Coulomb interaction, van der Waals force), and bistability or multiple of the molecular orientation. To bring stability. Also, they can be used as a spacing group to provide an appropriate three-dimensional framework, and molecules can be packed together while providing a space for rotation for each rotor. They are hydrogen, heteroatoms (eg N, O, S, P, B, F, Cl, Br and I), functional groups having at least one said heteroatom, hydrocarbons (either saturated or unsaturated) ), Or substituted hydrocarbons.
[0105]
Letter G₁Is a bridging group. The function of the bridging group is to connect the stator and rotor or connect two or more conjugated rings to obtain the desired chromophore. Bridging groups are heteroatoms (eg, N, O, S, P, etc.), or functional groups having at least one of the heteroatoms (eg, NH or NHNH), hydrocarbons (saturated or unsaturated). Or any one of substituted hydrocarbons.
[0106]
The letter W is an electron withdrawing group. The function of this group is to adjust the reactivity of the lactone group of the molecule so that the molecule can be smoothly separated or recombined (bond breakage or formation) under the influence of the applied external electric field. is there. The electron withdrawing group is a carboxylic acid or a derivative thereof (for example, ester or amide), nitro, nitrile, ketone, aldehyde, sulfone, sulfuric acid or a derivative thereof, a hetero atom (for example, F, Cl, or the like), or the above hetero atom Any of functional groups having at least one of (for example, F, Cl, Br, N, O, S, etc.), hydrocarbons (either saturated or unsaturated hydrocarbons), or substituted hydrocarbons Can be.
[0107]
The uppermost molecular structure has a relatively small bandgap state than the lowermost molecular structure.
[0108]
Another example of the field induced bandgap change caused by the breakdown of the extended π bond conjugate via charge recombination and σ bond formation is shown below (Example 6).
[0109]
[Chemical 8]

[0110]
Here, the letter Q is used to indicate a connecting unit between two phenyl rings. The connecting unit can be any of S, O, NH, NR, hydrocarbons or substituted hydrocarbons.
[0111]
Character Con₁And Con₂Is a connecting group between one molecule and another molecule, or between one molecule and a solid substrate (eg, metal electrode, inorganic or organic substrate, etc.). They can be hydrogen, heteroatoms (ie, N, O, S, P, etc.), or functional groups containing at least one of the heteroatoms (eg, NH), hydrocarbons (either saturated or unsaturated). Or any of substituted hydrocarbons.
[0112]
Letter R₁And R₂Represents a spacing group incorporated into the molecule. The function of these spacer units is to provide an appropriate three-dimensional framework to allow molecules to be dense while providing a space for rotation for each rotor. They can be any of hydrogen, hydrocarbons (either saturated or unsaturated), or substituted hydrocarbons.
[0113]
Letter J₁, J₂, J₃And J₄Represents a tuning group incorporated into the molecule. The function of these tuning groups (eg, OH, NHR, COOH, CN, nitro, etc.) is to provide appropriate functional effects (eg, both inductive and resonant effects) and / or steric effects. The functional effect is the molecular band gap (ΔE_{HOMO / LUMO}) To obtain not only the desired optical properties of the molecule but also the electronic properties. Steric effects are steric hindrance, intermolecular or intramolecular interaction forces (eg hydrogen bonds, Coulomb interactions, van der Waals forces) that adjust the molecular conformation and To provide multiple stability. Also, they can be used as a spacing group to provide an appropriate three-dimensional framework, and molecules can be packed together while providing a space for rotation for each rotor. They are hydrogen, heteroatoms (eg N, O, S, P, B, F, Cl, Br and I), functional groups having at least one of the heteroatoms, hydrocarbons (saturated or unsaturated) Or any of substituted hydrocarbons.
[0114]
Letter G₁Is a bridging group. The function of the bridging group is to connect the stator and rotor or connect two or more conjugated rings to obtain the desired chromophore. Bridging groups are heteroatoms (eg, N, O, S, P, etc.), or functional groups having at least one of the heteroatoms (eg, NH or NHNH), hydrocarbons (saturated or unsaturated). Or any one of substituted hydrocarbons.
[0115]
The letter W is an electron withdrawing group. The function of this group is to adjust the reactivity of the lactone group of the molecule so that the molecule can smoothly separate or recombine (break or form bonds) under the influence of an applied external electric field. That is. The electron withdrawing group is a carboxylic acid or a derivative thereof (for example, ester or amide), nitro, nitrile, ketone, aldehyde, sulfone, sulfuric acid or a derivative thereof, a hetero atom (for example, F, Cl, or the like), or the above hetero atom Any of functional groups, hydrocarbons (either saturated or unsaturated), or substituted hydrocarbons having at least one of (eg, F, Cl, Br, N, O, S, etc.) It can be.
[0116]
Again, the uppermost molecular structure has a relatively small bandgap state than the lowermost molecular structure.
[0117]
The present invention makes ink or dye molecules active devices that can be switched using an external electric field by a mechanism entirely different from any previously described electrochromic or chromogenic material. The general concept is to utilize a modified crystal violet lactone type molecule, where the lactone C—O bond is sufficiently unstable and under the influence of an applied electric field, the bond Can be destroyed and formed (see Examples 5 and 6 above).
[0118]
In the process of breaking the C—O bond, positive and negative charges are generated. The generated charges are separated and move in the opposite direction parallel to the applied external electric field (upper part of the molecule) or bond rotation (lower part of the molecule) occurs. Two aromatic rings (upper and lower parts) with an extended dipole of the molecule are completely conjugated, resulting in a color (red shift) (see Example 5). However, the molecule has intermolecular and / or intramolecular forces, such as hydrogen bonds, Coulomb forces, or dipole-dipole interactions and steric repulsion, or stabilizes both charges in this particular orientation. Designed by a permanent external electric field. Therefore, a large electric field is required to remove the molecule from its initial orientation. Once switched to a particular orientation, the molecule will remain in that orientation until switched.
[0119]
When a reverse electric field is applied (Example 6), both charges tend to rearrange in the direction of the reverse external electric field. The positive charge in the upper part of the molecule moves from the side of the molecule to the central part of the molecule (position of triarylmethane) by delocalization of non-bonded electrons, or π electrons, or π and non-bonded electrons. Similarly, the lower part of the negatively charged molecule tends to approach the external electric field due to the rotation of C—C bonds. An important element of molecular design is CO₂ ⁻And a steric and static repulsive force between the lower part of the molecule (the negatively charged part) and the Y group that prevents it from rotating completely up to 180 ° inversion. Instead, the rotation is stopped at an angle of approximately 90 ° from the initial orientation by a large group of steric interactions across the lower and upper portions. Furthermore, this 90 ° orientation is stabilized by the formation of C—O bonds and charge recombination. In this process, tetrahedral carbon (isolator) is formed at the position of triarylmethane. The molecular conjugation is broken and HOMO and LUMO are no longer delocalized throughout the upper part of the molecule. This has the effect of reducing the volume occupied by the electrons, thereby increasing the HOMO-LUMO gap. In this process, a blue-shifted color or a transparent state occurs.
[0120]
In the case of colored ink and dye molecules, the limitation of positive charge transfer between one end of the molecule and the central position is extremely important. Another important factor is that the rotor (lower part of the molecule) is between two states that are separated from the stator (upper part of the molecule) by an optically meaningful angle (nominally 10-170 °). Is the ability to switch between. When the intramolecular charge separation reaches the maximum distance, the uppermost part of the molecule becomes fully conjugated. The π electrons of a molecule, or π electrons and non-bonded electrons, are delocalized throughout the uppermost region via their highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO). The effect is identical to that for quantum mechanical particles in the box, and when the box is the size of the whole molecule, ie when the orbitals are delocalized, the gap between HOMO and LUMO is relatively small . In this case, the molecular HOMO-LUMO gap is designed to yield the desired color ink or dye. The HOMO-LUMO gap for all parallel structures is different for various chemical groups (J₁, J₂, J₃, J₄And W) can be tuned by substituting on different aromatic rings of the molecule. Chemical substituents attached to the rotor and stator (J₁, J₂, J₃, J₄And, depending on the nature of W), if the rotor (lower part of the molecule) rotates by 10-170 ° with respect to the stator (upper part of the molecule), the increased HOMO-LUMO gap is Will correspond to a blue shifted color. If the shift is large enough, the molecule becomes transparent if the new HOMO-LUMO gap is large enough. Thus, the molecule can be switched between two colors or from one color to a transparent state.
[0121]
Examples 5 and 6 show two different states of a representative switchable molecule under the influence of an externally applied electric field. For this particular type of molecule, the azimuth axis of the molecule is perpendicular to the plane of the electrode used to switch the molecule, for example using Langmuir-Blodgett technology, vapor deposition, or electrochemical deposition. A sufficiently thick molecular film is grown so that Other deposition techniques suspend the molecule as a monomer / oligomer or solvent-based solution, apply it to a thick film coating (eg, reverse roll) or spin coat on the substrate, and then apply an electric field to align the molecules The coating is polymerized (for example by UV irradiation) or dried. A transparent conductor such as indium-tin oxide can be used on the electrode surface, and the film is grown so that the molecular axis is parallel to the surface of the electrode. Molecules form solids or liquid crystals, and large stator groups are fixed in place by intermolecular interactions or direct binding to the support structure, but the rotor is small enough to move within the molecular lattice.
[0122]
Model (3): Field-induced band gap change through molecular folding or stretching
FIG. 7 is a schematic of this model, which involves a field-induced bandgap change caused by a change in extended conjugation through molecular folding or stretching. As shown in FIG. 7, the molecule 730 consists of three parts 732, 734, and 736. Molecule 730 exhibits a relatively small band gap due to extended conjugation over most of the molecule. Application of an electric field causes the breakdown of the conjugate in molecule 730 due to molecular folding around the central portion 734, resulting in a larger band gap due to unextended conjugation over the majority of the molecule. . The reversal of the electric field causes the molecule 730 to expand and the molecule 730 returns to its original state. Extending and relaxing the central portion 734 of the molecule 730 has the same effect.
[0123]
In this model, the following requirements must be met:
(A) The molecule must have at least two parts.
(B) Some parts must have HOMO, LUMO, and non-bonded electrons contained in adjacent orbitals, or π electrons, or π electrons and non-bonded electrons.
(C) The molecule may be symmetric or asymmetric with respect to the acceptor group on one side and the donor group on the other side.
(D) at least two parts of the molecule are useful for stabilizing both folding and extension states by intramolecular or intermolecular forces such as hydrogen bonds, van der Waals forces, coulomb attractive forces or metal complexation. It has a functional group.
(E) The state of molecular folding or stretching must be addressable by an electric field.
(F) In at least one state (probably fully extended), the molecule's non-bonded electrons, or π electrons, or π electrons and non-bonded electrons are sufficiently delocalized, and the molecule's π and The p-electrons are localized or only partially delocalized in other states.
(G) The non-localization of non-bonded electrons, or π electrons, or π electrons and non-bonded electrons in the molecule, while the band gap of the molecule is folded or stretched by an applied external electric field. Depending on the degree of conversion, this type of change also affects the conductivity of the molecule.
(H) This property allows these types of molecules to be applied to optical or electrical switches, gates, storage devices or display applications.
[0124]
An example of a field induced gap change through molecular folding or elongation is shown below (Example 7).
[0125]
[Chemical 9]

[0126]
Where R₁And R₂Represents a spacing group incorporated in the molecule. These spacing groups can be any of hydrogen, hydrocarbons (either saturated or unsaturated) or substituted hydrocarbons.
[0127]
Letter J₁, J₂, J₃, J₄And J₅Represents a tuning group incorporated into the molecule. The function of these tuning groups (eg, OH, NHR, COOH, CN, nitro, etc.) is to provide appropriate functional effects (eg, both inductive and resonant effects) and / or steric effects. The functional effect is the molecular band gap (ΔE_{HOMO / LUMO}) To obtain not only the desired optical properties of the molecule but also the electronic properties. Steric effects are steric hindrance, intermolecular or intramolecular interaction forces (eg hydrogen bonds, Coulomb interactions, van der Waals forces) that adjust the molecular conformation and To provide multiple stability. They can also be used as spacing groups. They are hydrogen, heteroatoms (eg N, O, S, P, B, F, Cl, Br and I), functional groups having at least one of the heteroatoms, hydrocarbons (saturated or unsaturated) Or any of substituted hydrocarbons.
[0128]
The letters Y and Z are functional groups that will form intermolecular or intramolecular hydrogen bonds. These functional groups can be any of SH, OH, amines, hydrocarbons, or substituted hydrocarbons.
[0129]
The upper molecule in the figure has a larger band gap due to conjugation localizing to various parts of the molecule, while the lower molecule is due to extended conjugation over the majority of the molecule. Have a smaller band gap.
[0130]
Techniques disclosed and claimed herein for forming optical switches (micrometers or nanometers) include displays, electronic books, rewritable media, electrically adjustable optical lenses, windows and mirrors. Can be used to fabricate, for example, an optical crossbar switch for sending signals from one of a number of input channels to one of a number of output channels.
[Industrial applicability]
[0131]
The field switchable molecules disclosed herein are expected to find use in optical devices composed of microscale and even nanoscale components, as well as in various visual displays.
[Brief description of the drawings]
[0132]
FIG. 1 is a schematic (perspective perspective view) of a two-color (eg, black and white) display screen configuration for use in accordance with the present invention.
1a is a detailed view of the colorant layer element of the display screen shown in FIG.
FIG. 2 is a schematic diagram (perspective view) of a full color display screen configuration for use in accordance with the present invention.
FIG. 3 is a schematic diagram of a scan addressing embodiment of a two-color display screen configuration for use in accordance with the present invention.
FIG. 4 is a schematic model (rotator / stator method model) showing electric field-induced band gap changes through changes in molecular conformation.
FIG. 5a shows a molecule consisting of a central rotor part with dipoles and two end stator parts.
Fig. 5b is a schematic (perspective view) of the molecule of Fig. 5a showing a flat state where the rotor and stator are all on the same plane.
Fig. 5c is a schematic (perspective view) of the molecule according to Fig. 5a showing a rotating state in which the rotor is rotated 90 ° relative to the stator.
FIG. 6a: Schematic model showing field-induced bandgap changes caused by extended conjugation changes via charge separation or recombination with increasing or decreasing band localization
FIG. 6b: Schematic model showing field induced bandgap changes caused by charge separation or recombination and changes in extended conjugation via π bond breakage or formation.
FIG. 7: Schematic model showing field-induced band gap changes via molecular folding or extension

Claims (13)

Electric field-driven optical switch (101, 205, 207, 209), wherein the molecular system (430, 630, 630 ′, 730) is
(1) Molecular conformational change or isomerization,
(2) change of extended conjugation via chemical bond change that changes the band gap,
Or
(3) molecular folding or stretching,
An optical switch in which an electric field induced bandgap change is caused by one of the mechanisms. The electric field induced band gap change is caused by a change in molecular conformation or isomerization, and the molecular system (430) comprises at least one stator part (434) and at least one rotor part (432), and the rotor (432) is rotated from the first state to the second state by the applied electric field, wherein in the first state there is an extended conjugate throughout the molecular system, so that the band gap is relatively small, and The optical switch (101, 205, 207, 209) according to claim 1, wherein, in the second state, the extended conjugate is destroyed, resulting in a relatively large band gap. The electric field induced bandgap occurs through a chemical bond change that changes the bandgap, in which case the electric field induced bandgap change is caused by extended conjugation via charge separation or recombination with increased or decreased band localization. 2. The optical switch (101, 205, 207, 209) according to claim 1 caused by a change. The molecular system (630) consists of two parts (632, 634), and the change from the first state to the second state is caused by an applied electric field, and the change is from the first state to the second state. With charge separation when changing to a state, resulting in a relatively large bandgap with little π delocalization, and the change changing from the second state to the first state 4. An optical switch (101, 205, 207, 209) according to claim 3, which is accompanied by charge recombination, resulting in a relatively small band gap with relatively large π delocalization. The electric field induced bandgap occurs through a chemical bond change that changes the bandgap, where the electric field induced bandgap change is caused by an extended conjugate via charge separation or recombination and π bond breakage or formation. The optical switch (101, 205, 207, 209) according to claim 3 caused by a change. The molecular system (630 ′) is composed of two parts (632 ′, 634 ′), and a change from the first state to the second state is caused by an applied electric field, and the change is changed from the first state to the first state. Accompanied by charge separation when changing to the second state, in which the extended conjugation exists throughout the molecular system (630 ′), resulting in a relatively large band gap, and The optical switch (101) according to claim 5, wherein in the second state, the extended conjugate is broken and separate positive and negative charges are generated in the molecular system, resulting in a relatively small band gap. 205, 207, 209). The field-induced band gap change occurs through molecular folding or stretching, and the molecular system (730) is coupled to three parts (732, 734, 736), respectively, a second central part (734). It consists of a first part (732) and a third part (736), and the change from the first state to the second state is caused by the applied electric field, and the change is in the vicinity of the second part or the second part. In the first state, there is an extended conjugate throughout the molecular system (730), resulting in a relatively small band gap, and in the second state, The optical switch (101, 205, 207, 209) according to claim 1, wherein the extended conjugate is destroyed, resulting in a relatively large band gap. The optical switch (101, 205, 207, 209) of claim 1, wherein the molecular system (430, 630, 630 ', 730) is bistable and provides a non-volatile component. The optical switch (101) of claim 1, wherein the molecular system (430, 630, 630 ', 730) has a low activation barrier between essentially various states, resulting in a fast but volatile switch. 205, 207, 209). The molecular system (430, 630, 630 ′, 730) has three or more switchable states, thereby applying a gradually decreasing or increasing electric field to the molecular system (430, 630, 630 ′). , 730) so that the optical characteristics are continuously adjusted to form a volatile switch or to apply a voltage pulse to a switch having at least one activation barrier so that the color is changed instantaneously. The optical switch (101, 205, 207, 209) according to claim 1. The optical switch (101, 101) of claim 1, wherein the molecular system (430, 630, 630 ', 730) changes between a transparent state and a colored state, or between one colored state and another colored state. 205, 207, 209). The optical switch (101, 205, 207, 209) of claim 1, wherein the molecular system (430, 630, 630 ', 730) varies between one refractive index and another. The molecular system of claim 1 (430, 630, 630 ', 730).

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