JP2006222383A - Functional thin film element and its manufacturing method, and article using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional thin film element which is driven with a low voltage and has a longer life and an article using the same, and to provide a manufacturing method for the functional thin film element which lowers costs for materials and greatly reduces process costs. <P>SOLUTION: The functional thin film element has a substrate 2, an anode 3 formed on the substrate 2, an organic metal complex layer 4 formed on the anode 3, a functional thin film (organic light emitting layer 5) formed on the organic metal complex layer 4, and an anode 6 formed on the functional thin film (organic light emitting layer 5). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a functional thin film element used as an element typified by an organic EL element, a solar cell, a light control element, and a transistor element (FET element), a production method thereof, and an article using the functional thin film element.

  Recent progress in information technology and IT technology has been tremendous, including luminescence elements that emit light, solar cells that absorb light and convert energy, and liquid crystal systems and electrochromic systems that change light transmittance when the voltage is turned on and off. Development of dimming elements is accelerating.

  These elements have an anode and a cathode disposed on both sides thereof, and in particular, a transparent electrode is disposed on the electrode on the side on which light is to be incident or emitted, and the light generated in the element is emitted to the outside. Or light from the outside is incident on the inside of the device.

  Recently, plasma display, organic electroluminescence (EL) display, and field emission display with high brightness and wide viewing angle have been intensively researched and developed for TV. In addition to TVs, transparent electrodes are indispensable for displays for personal computers, flat panel displays typified by automobile navigation, mobile phones, electronic paper, and personal computers for mobile use.

  Elements represented by organic EL elements, solar cells, dimming elements, and transistor elements (FET elements) are basically constructed in a sandwich type with both anode and cathode electrodes sandwiched between both surfaces of a functional thin film. Looking at these elements mechanically, the movement of charge carriers (electrons and holes) at the interface between the two electrodes and the functional thin film, or between the functional thin film and the functional thin film, that is, at the junction interface Actively used to develop electronic functions or optical functions.

  Furthermore, an organic electroluminescence (EL) element which has recently been attracting attention will be described. A longitudinal sectional view of an organic EL element using a functional thin film element is shown in FIG. The organic EL element 20 has an anode 22 (transparent electrode (for example, ITO: Indium Tin Oxide)) formed on a transparent substrate (glass, ceramics, resin) 21, and a functional thin film that is a light emitting layer on the anode 22. 23 and a cathode (for example, Mg · Ag) 24 are formed. The anode 22 and the cathode 24 are connected to the positive electrode and the cathode of the DC power supply 25, respectively.

  When a voltage is applied between the anode 22 and the cathode 24, holes are injected into the functional thin film (light emitting layer) 23 from the anode 22 side, and electrons from the cathode 24 side exceed the potential barrier height Δφ at each junction interface. Then, it is injected into the functional thin film (light emitting layer) 23, and the electron and hole are recombined to emit light. The emitted light is emitted from the transparent substrate 21 and the anode 22 side formed from a light transmissive material.

FIG. 10 shows a band structure schematically showing the flow of electrons and holes of the organic EL element 20 and the potential barrier at the junction interface. In the structure shown in FIG. 10, the magnitude φ ₂ of the transparent anode (ITO electrode) is about 4.5 eV to 4.7 eV (electron volts: hereinafter abbreviated as eV), and a functional thin film (light emitting layer) ) since the size phi _H in ionization potential 23 is approximately 5.4 eV~5.8eV, height Δφ of the potential barrier is very large and approximately 0.7EV～1.3EV. When the height Δφ of the potential barrier increases, it becomes difficult for holes to be injected from the anode 22, and a high voltage has to be applied between the anode 22 and the cathode 24 in order to obtain a target light emission luminance. For this reason, low voltage driving of the organic EL element 20 has been hindered. Further, when holes are hardly injected, it becomes difficult to secure an injection balance with electrons injected from the cathode 24, and the stability of light emission cannot be maintained. Approaches to solve such problems are being carried out.

  The first is a method in which the anode (transparent electrode ITO) is fixed and a buffer layer having an intermediate value of ionization potential between the anode and the functional thin film (light emitting layer) is inserted.

The second method is a method in which the anode (transparent electrode ITO) is fixed, and the light emitting layer having a value relatively close to the ionization potential φ ₂ of the anode is selected.

The third method is a method in which a functional thin film (light emitting layer) is fixed and an anode having a value relatively close to the magnitude φ _H of the ionization potential of the functional thin film (light emitting layer) is selected.
"Story of organic EL", page 49, edited by Nikkan Kogyo Shimbun

  However, the three methods described above have their respective problems.

  In the first method, when the buffer layer is inserted, the energy difference between the anode and the functional thin film (light-emitting layer) can be changed stepwise, so that when viewed from the anode side, the holes that are carriers are potential barriers. The height Δφ can be easily overcome. However, the magnitude φ of the ionization potential of the buffer layer cannot be arbitrarily controlled, and the process by coating and curing increases, which causes a cost increase and is not practical.

  In the second method, when a light emitting material is selected by paying attention to the magnitude φ of the ionization potential, there is a problem that a light emission color cannot be freely selected and a high light emission efficiency cannot be obtained.

In the third method, the ionization potential of the light emitting layer is satisfied after satisfying the low resistance, high light transmittance, electrode pattern formability (eg, etching property) and surface smoothness required for the anode (transparent electrode ITO). It was extremely difficult to select an anode having a value close to the size φ _H. In addition to the most commonly used ITO electrodes as the anodes that require transparent conductivity, ATO (Antimon doped Tin Oxide), FTO (F doped Tin Oxide), and ZnO (Zinc Oxide) electrodes are also known. However, these electrodes have the same problems as the ITO electrodes.

  In this way, functional elements that control the height φ of the potential barrier at the junction interface between the anode and the light emitting layer have been developed, and commercialization of displays and solar cell modules using these functional elements is desired. Actually, it was inevitable to use a combination of layers based on the physical properties (ionization potential) inherent to the metal, oxide semiconductor, and functional thin film.

  The present invention has been made to solve the above-described problems. That is, the functional thin film element of the present invention includes a substrate, an anode formed on the substrate, and an organometallic complex layer formed on the anode. And a functional thin film formed on the organometallic complex layer and a cathode formed on the functional thin film.

  In the method for producing a functional thin film element of the present invention, a π-conjugated polymer soluble in water or a solvent or a conductive nanoparticle and a polymer resin having optical transparency are formed on a substrate using a printing technique. After forming an anode with the material containing it, forming an organometallic complex layer on the anode, then forming a functional thin film with a π-conjugated polymer on the organometallic complex layer, and using a printing technique on this functional thin film The gist is to form the cathode with a π-conjugated polymer.

  An article using the functional thin film element in the present invention includes any one of the functional thin film elements selected from a display body, an illumination body, a photovoltaic module, and a semiconductor module using the functional thin film element described above. The gist is that the article is used.

  According to the functional thin film element of the present invention, by forming an organometallic complex layer having a cation on the anode surface, the height of the potential barrier at the junction interface is controlled, driving at a low voltage and further extending the life. It has been realized.

  According to the method for producing a functional thin film element of the present invention, it is possible to significantly reduce the material cost and the process cost.

  According to the article using the functional thin film element of the present invention, it is possible to drive at a low voltage and realize a long life.

  Hereinafter, a functional thin film element and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1A shows a longitudinal sectional view of an organic EL element 1 using the functional thin film element according to the embodiment of the present invention. The organic EL element 1 includes a substrate 2, an anode 3 formed on the substrate 2, an organometallic complex layer 4 formed on the anode 3, and an organic light emitting layer 5 ( Functional thin film) and a cathode 6 formed on the organic light emitting layer 5 (functional thin film). The anode 3 and the cathode 6 are respectively connected to the anode (positive electrode) and the cathode (negative electrode) of the DC power source 7. It is connected. The substrate 2 and the anode 3 are made of a light transmissive material, and light emitted from the organometallic complex layer 4 is transmitted through the substrate 2 and the anode 3.

  In this way, the organometallic complex layer 4 is formed at the junction interface between the anode 3 and the organic light emitting layer 5 to reduce the ionization potential of the anode 3 material. Then, when viewed from the electron side which is a carrier, the potential barrier Δφ at the junction interface between the anode 3 and the organometallic complex layer 4 is lowered, and an enlarged cross-sectional view of the anode 3 and the organometallic complex layer 4 in FIG. As shown in FIG. 4, holes can be easily injected from the anode 3 into the organic light emitting layer 5. Here, although the term “ionization potential” is used for the anode material ITO, the ionization potential is defined as energy necessary for extracting electrons from neutral atoms to the outside. It should be noted that ITO is a semiconductor, and strictly speaking, it is appropriate to use the term “work function” instead of “ionization potential”. However, since both are basically the same concept, in this application, “ionization potential” is used. "Is used.

Fig. 2 (a) shows the band structure when ITO electrode is used for the anode 3 and PPV (polyphenylene vinylene) is used for the organic light-emitting layer 5, and Fig. 2 (b) shows a partially enlarged view. Explained. The ionization potential φ ₂ of the ITO electrode (anode 3) is −4.7 eV, the ionization potential of the organic light-emitting layer 5 formed from PPV is about −5.2 eV to −5.5 eV, and the HOMO level φL is about −5.1 eV. The potential barrier Δφ at the junction interface between the anode 3 and the organic light emitting layer 5 is theoretically about 0.6 eV. In addition, in the value of the ionization potential, the sign of-(minus) is attached because it is based on the vacuum level (0 eV) (for example, see FIG. 2 (a)).

As described above, when a large potential barrier of about 0.6 eV is generated at the junction interface between the anode 3 and the organic light emitting layer 5, a high voltage is applied between the anode 3 and the cathode 6 in order to obtain a desired light emission luminance. Must. However, when a high voltage is applied between the anode 3 and the cathode 6, the light stability and the light emission lifetime in the organic light emitting layer 5 are lowered and cannot be practically used. Therefore, an ultrathin organometallic complex layer 4 is formed at the junction interface between the anode 3 and the organic light emitting layer 5, the metal element in the organometallic complex layer 4 is cationized, and this cation is applied to the surface of the anode 3. When moved, it is considered to be equivalent to a state in which the surface of the anode 3 is doped with cations. As a result, the value of the ionization potential φ ₂ of the anode 3 is considered to increase.

Although the mechanism by which the value of the ionization potential φ ₂ of the anode 3 increases when the organometallic complex layer 4 is formed is not clear, it can be explained as follows.

  A state of the cation 8 moving to the surface of the anode 3 through the organometallic complex layer 4 is shown in FIG.

未処理状態の陽極３表面を(a)に示し、有機金属錯体層４から脱離した陽イオン８が陽極３表面にドープされた状態を(b)に示す。陽極３表面に陽イオン８がドープされると、陽極３表面での電気的安定性に欠ける状態となり、電気的中性を保つため負に帯電した陰イオン９が誘起されて陽極３表面に電気二重層１０が形成される。この様子を(c)に示す。陽極３表面に電気二重層１０が形成されると、陽極３に存在する電子は最表面に位置する陰イオン９の存在により反発し合う確率が増大し、電子は外部に放出され難くなり、陽極３のイオン化ポテンシャルφ₂の値が増大するものと推察される。

The surface of the anode 3 in the untreated state is shown in (a), and the state in which the cation 8 desorbed from the organometallic complex layer 4 is doped on the surface of the anode 3 is shown in (b). When the cation 8 is doped on the surface of the anode 3, the electrical stability on the surface of the anode 3 is lacked, and negatively charged anions 9 are induced to maintain electrical neutrality, and the surface of the anode 3 is electrically charged. A double layer 10 is formed. This is shown in (c). When the electric double layer 10 is formed on the surface of the anode 3, the probability that electrons existing in the anode 3 repel each other due to the presence of the anion 9 located on the outermost surface increases, and the electrons are hardly emitted to the outside. It is presumed that the ionization potential φ ₂ of 3 increases.

The ionization potential φ ₂ on the surface of the anode 3 on which the electric double layer 10 is formed can be measured using photoelectron spectroscopy in the atmosphere (AC-2, manufactured by Riken Keiki Co., Ltd.). As shown in FIG. 4 (a), the wavelength of the monochromatic light is incident on the surface of the anode 3, the wavelength of the monochromatic light (in other words, the irradiation energy) is changed, and the photoelectrons jumping out from the surface of the anode 3 are countered ( (Not shown). Then, the photoelectrons are suddenly emitted from a certain threshold value. The measurement principle diagram of the ionization potential on the surface of the anode 3 is shown in FIG. A straight line A shows a photoelectron plot from the surface of the untreated anode 3 shown in FIG. 3A, and a straight line C shows an organometallic complex layer 4 formed on the surface of the anode 3 as shown in FIG. Thus, a photoelectron plot in a state where the electric double layer 10 is formed on the surface of the anode 3 is shown. The horizontal axis indicates the irradiation light energy (eV), the vertical axis indicates the half power (square root) of the photoelectron yield, and the intersection points 11 and 12 where the straight lines A and C intersect the irradiation light energy on the horizontal axis are ionization potentials. It becomes the value of. The value of the ionization potential of the straight line A is 4.7 eV, and the value of the ionization potential of the straight line C is 5.2 eV. As shown by the straight line C, the value of the ionization potential increases when the organometallic complex layer 4 is formed on the surface of the anode 3. It was proved. When the organometallic complex layer 4 is formed on the surface of the anode 3 in this manner, the electric double layer 10 is formed, and it is difficult for electrons to jump out due to the anion effect, and the value of the ionization potential is increased.

  In the organic EL element 1 shown in FIG. 1 described above, the organometallic complex layer 4 is formed at the bonding interface between the anode 3 and the organic light emitting layer 5 (functional thin film). A vertical cross-sectional view of the organic EL element 13 which may be formed between the (functional thin film) and the cathode 6 is shown in FIG. In addition, the same code | symbol is used for the structure same as the organic EL element 1, and the description is abbreviate | omitted. The organic EL element 13 is formed on the substrate 2, the cathode 3 formed on the substrate 2, the organic light emitting layer 5 (functional thin film) formed on the cathode 3, and the organic light emitting layer 5 (functional thin film). The formed organometallic complex layer 4 and the anode 6 formed on the organometallic complex layer 4 are included. At this time, FIG. 6 (a) shows a band structure when an ITO electrode is used for the anode 3 and PPV (polyphenylene vinylene) is used for the organic light emitting layer 5, and FIG. 6 (b) is a partially enlarged view of (a). Show. Also in this case, since the organometallic complex layer 4 is formed, the height of the potential barrier at the junction interface between the anode 3 and the organic light emitting layer 5 (functional thin film) can be controlled. The injection balance of electrons into the light emitting layer 5 (functional thin film) can be facilitated.

  Next, the constituent materials of the organic EL elements 1 and 13 will be described.

  The organometallic complex layer 4 is formed from an organic compound in which an organic molecule and a metal element are bonded at least.

  The organic molecules are (a) porphyrin ring, (b) phthalocyanine ring, (c) triphenylene ring (TP (Triphenylene) on the left, OT (o-Terphenyl) on the right), (d) metal shown in FIG. An organic molecule selected from a complex and (e) a pyromethene ring is preferred. In the figure, M represents a metal element.

  The metal element is either one kind of alkali metal element selected from Li, Na, K, Rb and Cs, or one kind of alkaline earth metal element selected from Be, Mg, Ca, Sr and Ba. It is preferable to use one of them.

  Thus, when a metal element is coordinated in an organic molecule in which a π electron cloud is developed to form an organometallic complex, the metal element is ionized relatively easily and becomes a cation, and the cation becomes rich on the surface of the anode 3. This is equivalent to a state in which the surface of the anode 3 is doped with cations. For this reason, holes can be easily injected from the anode 3 into the organic light emitting layer 5 (functional thin film). Among the exemplified organic molecules, in particular, a porphyrin ring, a phthalocyanine ring, or a triphenylene ring is preferable, but by having a structure in which a metal element is coordinated at the center of the cyclic structure, the metal element is relatively It is thought that it becomes easy to ionize easily. Further, when the organic molecule is made into a cyclic molecule, the organic molecule is stable even if it is dissolved in a solvent and mixed with other organic molecules. Therefore, when the organometallic complex layer 4 is formed on the surface of the anode 3, The bonded metal element ions (cations) are likely to be rich at the interface of the anode 3, and holes can be easily injected from the anode 3 into the organometallic complex layer 4 (functional thin film).

  Moreover, the magnitude of the ionization potential at the interface of the anode 3 varies depending on the type of the central metal element selected. Compared with Li, Na, K, Rb, and Cs in group Ia (alkali metals) of the periodic table, the value of ionization potential increases when an element with a small element number (high electronegativity) is used. There is a tendency. For example, when Li or Na is used as the central metal element of metal phthalocyanine, when Li is coordinated as the central metal element, the ionization potential value is larger than when Na is coordinated. Was recognized.

  Furthermore, the molecular weight of the organic molecules is preferably in the range of 250 to 25000. By setting the molecular weight in this range, the organic metal light-emitting layer 4 (functional thin film) containing metal element ions is subjected to a dry process (for example, vacuum). It can be easily formed by vapor deposition) or a wet process. For organic molecules having a molecular weight of about 250 to several thousand, dry processes such as vacuum deposition can be applied, and it is also possible to form a laminated structure of organic thin films having different functional roles on a substrate (typical examples thereof). Is an organic EL device).

  In addition, organic molecules having a molecular weight of several thousand to 25,000 can be made into a solution by using a solvent corresponding to various polymers as a so-called polymer, and can be applied on the substrate by the various wet processes described above.

  The organometallic complex layer 4 is not limited to the exemplified materials as long as it has a metal element in an organic molecule and the metal element is easily liberated.

Furthermore, since the thickness of the organometallic complex layer 4 is related to the ease of movement of the anode 3 material, the cation in the organometallic complex layer 4 or the metal cation, it cannot be determined uniquely. It was found that the value of the ionization potential φ ₂ of the anode 3 can be arbitrarily controlled by making the organometallic complex layer 4 very thin. Specifically, the thickness (d ₀ ) of the organometallic complex layer is preferably 10 nm or less. When the thickness is within this range, the metal element constituting the organometallic complex layer is cationized, and the cation It has been found that the doping becomes more prominent and the amount of change in the ionization potential increases. This is considered to be an extremely important factor in releasing cations from the organometallic complex layer 4 and moving them to the surface of the anode 3, that is, doping. Thus, by controlling the ratio of the thickness d _o and the thickness d _f of the functional thin film of an organic metal complex layer (d _f / d _0), can be freely controlled ionization potential phi ₂ of the size of the anode surface found. This will be described below.

The ratio (d _f / d ₀ ) between the thickness d _f of the functional thin film and the thickness d _o of the organometallic complex layer 4 is plotted on the horizontal axis, and the change ΔI _p in the ionization potential is plotted on the vertical axis. This is shown in FIG. Here, the change ΔI _p of the ionization potential is expressed as a change amount based on the case where the organometallic complex layer is not formed on the anode.

The thickness d _f of the functional thin film, conducted in the organic EL element 1, electrons and holes are not inactivated as organic light-emitting layer, a sufficiently experiment thickness d _f of recombination can be functional thin as 100nm It was. As the organometallic complex layer 4 used in the experiment, three types in which all of magnesium porphyrin (MgPor), magnesium phthalocyanine (MgPC), and sodium porphyrin (NaPor) were polymerized were used.

As shown in FIG. 8, when the ratio (d _f / d ₀ ) is smaller than 1.0, the change amount ΔI _p of the ionization potential on the surface of the anode 3 is almost 0 and no substantial change is observed, but the ratio ( When d _f / d ₀ ) becomes 1.0 or more, the change amount ΔI _p of the ionization potential gradually increases. When the ratio (d _f / d ₀ ) is around 500, the change amount ΔI _p of the ionization potential shows a maximum value of about 0.8 eV. It can be seen that when the ratio (d _f / d ₀ ) is 500 or more, the change amount ΔI _p of the ionization potential gradually decreases, and when the ratio (d _f / d ₀ ) is 10 ⁵ or more, it is almost zero. Thus the ratio (d _f / d ₀₎ from becoming becomes less than 1.0 and the amount of change [Delta] I _p is substantially 0 ionization potential, the thickness d _o of the organometallic complex layer 4 becomes substantially thicker, organometallic complexes Layer 4 reflects the properties of the bulk (insulator or semiconductor level when viewed in terms of electrical characteristics), and is a phenomenon that can occur in ultra-thin nano-order layers (a process in which cations are doped). It is because it is thought that it is impossible. On the other hand, the ratio (d _f / d ₀₎ from becoming a variation [Delta] I _p is 0 ionization potential exceeds ¹⁰⁵ does not reach the threshold value (active site) that cations are doped in the anode 3 surface It is thought that it is from. That is, it is presumed that the cation remains at the level where it is scattered and does not lead to the phenomenon of ion doping.

As is clear from FIG. 8, although there are some differences in characteristics depending on the three types of organometallic complexes used in the experiment, the characteristics are generally similar, and the ionization potential is 1 <(d _f / d ₀ ) <10 ⁵ , showing a change, and region A was found to be in the proper range. In particular, when the ratio is 50 to 3000 and the range is in the region B, it has been found that the amount of change ΔI _p of the ionization potential exceeds 0.4.

  In the embodiment of the present invention, the organic EL element 1 is exemplified as the functional thin film element, but the functional thin film element of the present invention can also be used as an organic solar cell or an organic laser. When a functional thin film element is used as the organic EL element 1 or solar cell, a transparent electrode is used as an electrode on the surface from which light is emitted or incident. Generally, ITO (Indium Tin Oxide) or ZnO (Zinc Oxide) is used as the material for the transparent electrode. This is because of its low surface resistance and high transmittance, and it is easy to form a circuit pattern by etching. This is because it has advantages. In particular, ITO is widely used because it has this advantage, but has the following disadvantages. Since ITO is a ceramic thin film, it lacks flexibility and it is difficult to form an ITO thin film on an organic substrate with low heat resistance or on an organic thin film. I can't. And since the ITO thin film is formed mainly using a vacuum process (for example, sputtering, ion plating, vapor deposition, etc.), the film formation speed is slow and a large capital investment is required, resulting in high costs. Cannot be avoided. For this reason, the anode is preferably formed from the following two types of materials.

  The first is a material containing at least conductive nanoparticles and a light-transmitting polymer resin. According to this material, the stability of the organometallic complex layer 4 can be improved, and the flexibility of the organic EL element 1 (functional thin film element) can be improved. The conductive nanoparticles are composed of one element selected from Au, Ag, Pt, Pd, Ni, Cu, Zn, Al, Sn, Pb, C, and Ti, or one element selected from these elements. It is preferable to make it the compound containing. The particle size of the conductive nanoparticles is preferably about 50 nm or less. When the particle size is 50 nm or less, the particle size of the conductive nanoparticles is smaller than the wavelength λ (380 to 780 nm) of incident light in the visible light region. The particle size is reduced to about 1/10 or less of the particle size, and the light transmittance is increased. The conductive nanoparticles are not limited to a spherical shape, and may be needle-like or fibrous.

  The second is a π-conjugated material. When the anode is formed from a π-conjugated material, the surface resistance and the light transmittance can be reduced by the action of π electrons in the conjugated double bond. In particular, the π-conjugated material is preferably a polymer material that is soluble in water or a solvent. For example, polypyrrole, polyacetylene, polyaniline, polythiophene, polyisothianaphthene, polyfuran, polyselenophene, polytellurophene, poly It is preferable to use at least one selected from thiephenvinylene, polyparaphenylenevinylene and derivatives thereof. Furthermore, in order to increase conductivity, it is better to use a material doped with a π-conjugated material. Specifically, doped polypyrrole, doped polyaniline, doped polythiophene, polyacetylene. (Doped Polyacethilene), polyisothianaphthene (doped Polyisothianaphtene), and at least one selected from these derivatives are preferable. Thereby, low resistance and light transmittance are good, and further desired optical functions such as color development and photovoltaic power can be exhibited.

  Furthermore, as the anode material, it is preferable to use a kind of π-conjugated material selected from polyethylenedioxythiophene (PEDOT), polypropylene oxide (PO), and derivatives thereof that are highly soluble in water or a solvent. In the former case, PEDOT polyethylenedioxythiophene): PSS (polystyrene sulfonic acid) can be mentioned as a representative example. This makes it easy to handle and makes it easy to use various printing methods as appropriate.

  In addition, the above-described π-conjugated material is preferably used as the anode 3 or the organometallic light emitting layer 4 (functional thin film). By forming the anode 3 or the organometallic light emitting layer 4 (functional thin film) from a π-conjugated material, the cation doping from the organometallic complex layer 4 is stabilized, and the flexibility of the organic EL element 1 is also improved. be able to. Furthermore, according to the π-conjugated material, the anode and the functional thin film can be continuously applied and printed on a flexible substrate using an all-wet process, and then the manufacturing process is performed by curing. A functional thin film element that can be greatly simplified, improved in performance and reduced in cost can be obtained.

  The substrate should have a high average light transmittance in the visible light region, and depends on the thickness and surface smoothness of the substrate, but from a practical viewpoint, the average light transmittance of the substrate is 80% or more, and more than 85%. It is preferable to do. When the average light transmittance of the substrate is increased, loss due to light scattering or absorption can be reduced as much as possible. Therefore, light emitted from the functional thin film is emitted to the outside via the substrate, or light from the outside of the substrate is emitted to the functional thin film. Can be easily imported.

  Further, when the functional thin film element is curved or has a three-dimensional shape, flexibility of the substrate is required. Therefore, it is preferable to form the substrate from a polymer resin film.

  In addition, in-plane birefringence Δn (an in-plane refractive index anisotropy) of the polymer resin film affects the direction of light emission or incidence, so Δn ≦ 0.1 is preferable. This is because when the birefringence Δn exceeds 0.1, the light is emitted or incident in a specific direction (angle), which is not preferable for practical use.

  Polymer resin films having an average light transmittance of 80% or more and a birefringence Δn of 0.1 or less include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), It is preferable to select one selected from polyethersulfone (PES) and derivatives thereof. When a substrate is formed from such a polymer resin film, a highly flexible substrate is obtained, and when an organic EL element is formed, light emitted from the organometallic light emitting layer (functional thin film) is uniformly distributed outside the substrate. In addition, in the case of a solar cell, light incident from the outside of the substrate can be incident on the organometallic light emitting layer (functional thin film) without light loss in the substrate. it can.

  Next, a method for manufacturing a functional thin film element according to an embodiment of the present invention will be described. For example, it is preferable to manufacture a functional thin film element by any of the following methods.

  In the first method, an anode is formed on a substrate by a printing technique using a material including a π-conjugated polymer soluble in water or a solvent, or a conductive nanoparticle and a light-transmitting polymer resin. After forming an organometallic complex layer on the anode, a functional thin film is formed on the organometallic complex layer with a π-conjugated polymer, and a π-conjugated polymer is formed on the functional thin film using a printing method. To form a functional thin film element.

  In the second method, a cathode is formed on a substrate by a printing technique using a material containing a π-conjugated polymer that is soluble in water or a solvent, or a conductive nanoparticle and a light-transmitting polymer resin. Then, after forming a functional thin film with a π-conjugated polymer on the cathode, an organometallic complex layer is formed on the functional thin film, and then a π-conjugated system is formed on the organometallic complex layer using a printing method. An anode is formed from a polymer to form a functional thin film element.

  In the method for manufacturing the functional thin film element described above, a method for forming an organometallic complex layer on the anode will be described below. The organometallic complex layer can be formed on the anode using a known method. Of course, it is preferable to take into consideration the type and layer thickness of the partner material to be doped, and the potential barrier to be set.

  As a known method, a soluble organometallic complex polymer is diluted with an appropriate solvent and applied by a casting method or a dipping method, or by using a spin coating method, a spray method, a gravure printing, or an ink jet method. . In particular, when the functional thin film is formed after the anode is formed into a circuit pattern, it is preferable to print the fine circuit directly using gravure printing or an inkjet method from the viewpoint of the width and pitch accuracy of the fine circuit pattern.

  Thus, the formation of the anode on the substrate, the cation doping, the formation of the functional thin film and the cathode can be successively processed by using the wet method by the printing method. As a result, the cost of the material can be reduced, and the process cost can be greatly reduced. Further, by forming an organometallic complex layer between the anode and the functional thin film, the functional thin film element can be driven at a low voltage, and the lifetime of the functional thin film element can be increased. Furthermore, when a flexible resin film is used for the substrate, flexibility can be ensured, so that a flexible functional thin film element, a curved display body and a three-dimensional display body using the functional thin film element can be obtained. Note that by forming the anode and the cathode from transparent electrodes, light can enter and exit easily, and light can enter and exit from the substrate side or the opposite side of the substrate.

  An article using the functional thin film element according to the embodiment of the present invention is any one selected from a display body, a lighting body, a photovoltaic module, and a semiconductor module using the functional thin film element described above. Is preferred. Moreover, it is preferable that the article using the functional thin film element according to the embodiment of the present invention is an article using the functional thin film element manufactured by using the method for manufacturing the functional thin film element described above. By using such an article, it is possible to drive at a low voltage and realize a long life.

  Hereinafter, more specific description will be given using examples.

Example 1
An anode made of an ITO transparent conductive film having a thickness of 150 nm was formed on a polyethylene terephthalate (PET) film as a substrate by sputtering. Thereafter, using a spin coating method, a magnesium porphyrin polymer (MgPor) was applied on the anode and cured to form an organometallic complex layer having a thickness of 50 nm on the substrate, which was used as a sample.

(Example 2)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, a magnesium porphyrin polymer (MgPor) was applied on the anode and cured to form an organometallic complex layer having a thickness of 10 nm on the substrate, which was used as a sample.

(Example 3)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, a magnesium porphyrin polymer (MgPor) was applied on the anode and cured to form an organometallic complex layer having a thickness of 2 nm on the substrate, which was used as a sample.

Example 4
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, a magnesium porphyrin polymer (MgPor) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.2 nm on the substrate, which was used as a sample.

(Example 5)
An anode made of an ITO transparent conductive film having a thickness of 150 nm was formed on a polyethylene terephthalate (PET) film as a substrate by sputtering. Thereafter, using a spin coating method, a magnesium porphyrin polymer (MgPor) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.01 nm on the substrate, which was used as a sample.

(Example 6)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 50 nm on the substrate, which was used as a sample.

(Example 7)
An anode made of an ITO transparent conductive film having a thickness of 150 nm was formed on a polyethylene terephthalate (PET) film as a substrate by sputtering. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form a 10 nm-thick organometallic complex layer on the substrate, which was used as a sample.

(Example 8)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 2 nm on the substrate, which was used as a sample.

Example 9
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form a 0.2 nm-thick organometallic complex layer on the substrate, which was used as a sample.

(Example 10)
An anode made of an ITO transparent conductive film having a thickness of 150 nm was formed on a polyethylene terephthalate (PET) film as a substrate by sputtering. Thereafter, using a spin coating method, magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.01 nm on the substrate, which was used as a sample.

(Example 11)
An anode made of an ITO transparent conductive film having a thickness of 150 nm was formed on a polyethylene terephthalate (PET) film as a substrate by sputtering. Thereafter, using a spin coating method, sodium phthalocyanine polymer (NaPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.2 nm on the substrate, which was used as a sample.

(Example 12)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, a lithium phthalocyanine polymer (NaPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.2 nm on the substrate, which was used as a sample.

(Example 13)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticles Pt having a particle size of 50 nm was applied by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 50 nm on the substrate, which was used as a sample.

(Example 14)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticles Pt having a particle size of 50 nm was applied by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied onto the anode and cured to form an organometallic complex layer having a thickness of 0.2 nm on the substrate, which was used as a sample.

(Example 15)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticles Pt having a particle size of 50 nm was applied by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.01 nm on the substrate, which was used as a sample.

(Example 16)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticle CNT having a diameter of φ10 nm × length of L100 nm was applied by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 50 nm on the substrate, which was used as a sample.

(Example 17)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticle CNT having a diameter of φ10 nm × length of L100 nm was applied by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied onto the anode and cured to form an organometallic complex layer having a thickness of 0.2 nm on the substrate, which was used as a sample.

(Example 18)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticle CNT having a diameter of φ10 nm × length of L100 nm was applied by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.01 nm on the substrate, which was used as a sample.

(Example 19)
A composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) was applied on a polyethylene terephthalate (PET) film as a substrate by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 50 nm on the substrate, which was used as a sample.

(Example 20)
A composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) was applied on a polyethylene terephthalate (PET) film as a substrate by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, a magnesium phthalocyanine polymer (MgPc) was applied onto the anode and cured to form an organometallic complex layer having a thickness of 0.2 nm on the substrate, which was used as a sample.

(Example 21)
A composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) was applied on a polyethylene terephthalate (PET) film as a substrate by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, magnesium phthalocyanine polymer (MgPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.01 nm on the substrate, which was used as a sample.

(Example 22)
A composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) was applied on a polyethylene terephthalate (PET) film as a substrate by a spin coater to form an anode having a thickness of 150 nm. Thereafter, by using a spin coating method, sodium phthalocyanine polymer (NaPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 50 nm on the substrate, which was used as a sample.

(Example 23)
A composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) was applied on a polyethylene terephthalate (PET) film as a substrate by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, sodium phthalocyanine polymer (NaPc) was applied on the anode and cured to form a 0.2 nm-thick organometallic complex layer on the substrate, which was used as a sample.

(Example 24)
A composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) was applied on a polyethylene terephthalate (PET) film as a substrate by a spin coater to form an anode having a thickness of 150 nm. Thereafter, using a spin coating method, sodium phthalocyanine polymer (NaPc) was applied on the anode and cured to form an organometallic complex layer having a thickness of 0.01 nm on the substrate, which was used as a sample.

(Example 25)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering. Thereafter, using a spin coating method, pyromethene polymer (MgPi) was coated on the anode and cured to form a 0.2 nm-thick organometallic complex layer on the substrate, which was used as a sample.

(Comparative Example 1)
On a polyethylene terephthalate (PET) film as a substrate, an anode made of an ITO transparent conductive film having a thickness of 150 nm was formed by sputtering, and this was used as a sample.

(Comparative Example 2)
On a polyethylene terephthalate (PET) film as a substrate, a dispersion containing 5 wt% of conductive nanoparticles Pt with a particle size of 50 nm was applied with a spin coater to form an anode with a thickness of 150 nm, which was used as a sample. .

(Comparative Example 3)
On a polyethylene terephthalate (PET) film that is a substrate, a dispersion liquid containing 5 wt% of conductive nanoparticle CNTs having a diameter of φ10 nm × length of L100 nm was applied by a spin coater to form a 150 nm-thick anode. This was used as a sample.

(Comparative Example 4)
On a polyethylene terephthalate (PET) film, which is a substrate, a composite liquid composed of polyethylene dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) is applied with a spin coater to form an anode with a film thickness of 150 nm. did.

The samples of Examples 1 to 25 and Comparative Examples 1 to 4 described above were placed in a desiccator and evacuated for 24 hours, and then the samples were taken out from the atmosphere and subjected to photoelectron spectroscopy (Riken Keiki Co., Ltd. AC) -2) was used to measure the ionization potential of each sample. The measurement results are shown in Table 1.

  As shown in Table 1, in each sample of Comparative Examples 1 to 4, since no organometallic complex layer was formed on the anode, each of Examples 1 to 25 in which the organometallic complex layer was formed Compared with the sample, the value of the ionization potential was high (a value close to the vacuum rank 0), and the amount of change in the ionization potential was slight. In particular, when the thickness of the organometallic complex layer is 10 nm or less, the amount of change in the ionization potential is significantly increased. Therefore, it has been found that the thickness of the organometallic complex layer should be 10 nm or less.

(a) is a longitudinal sectional view of an organic EL element using the functional thin film element according to the embodiment of the present invention, (b) is an anode and a light emitting layer of the organic EL element shown in (a) FIG. (a) is a figure which shows a band structure when ITO electrode is used for an anode and PPV (polyphenylene vinylene) is used for an organic light emitting layer, (b) is a partially enlarged view of (a). It is a diagram showing the state of the cation moving to the anode surface through the organometallic complex layer in the functional thin film element according to the embodiment of the present invention, (a) is a diagram showing the untreated anode surface, (b) is a diagram showing a state in which cations desorbed from the organometallic complex layer are doped on the anode surface, and (c) is a diagram showing a state in which an electric double layer is formed on the anode surface. (a) is a principle diagram for measuring photoelectrons jumping from the anode surface, and (b) is a principle diagram for measuring the ionization potential on the anode surface. (a) is a longitudinal sectional view of an organic EL element using a functional thin film element according to another embodiment of the present invention, (b) is a light emission and the anode of the organic EL element shown in (a) It is an expanded sectional view with a layer. (a) shows a band structure when an ITO electrode is used for the anode and PPV (polyphenylene vinylene) is used for the organic light emitting layer, and (b) is a partially enlarged view of (a). It is a figure which shows the molecular structure of the organic molecule which forms an organometallic complex layer, (a) is a porphyrin ring, (b) is a phthalocyanine ring, (c) is a triphenylene ring. It is a figure which shows the molecular structure of the organic molecule which forms an organometallic complex layer, (d) is a metal complex, (e) is a pyromethene ring. Is a diagram showing the ratio of the thickness d _o of the thickness d _f organometallic complex layer of the functional thin film layer formed on the anode (d _f / d _o), the relation between the ionization potential variation [Delta] I _p . It is a longitudinal cross-sectional view which shows the organic EL element using the conventional functional thin film element. It is a figure which shows the band structure which represented typically the flow of the electron of an organic EL element, the hole, and the electric potential barrier in a junction interface.

Explanation of symbols

1 ... Organic EL device,
2 ... Board,
3 ... Anode,
4 ... Organometallic complex layer,
5 ... Organic light emitting layer,
6 ... cathode,
7 ... DC power supply,

Claims (22)

A substrate,
An anode formed on the substrate;
An organometallic complex layer formed on the anode;
A functional thin film formed on the organometallic complex layer;
A functional thin film element comprising: a cathode formed on the functional thin film. A substrate,
A cathode formed on the substrate;
A functional thin film formed on the cathode;
An organometallic complex layer formed on the functional thin film;
A functional thin film element comprising: an anode formed on the organometallic complex layer.   The organometallic complex layer is a kind of alkali metal element selected from Li, Na, K, Rb and Cs, or a kind of alkaline earth metal selected from Be, Mg, Ca, Sr and Ba. 3. The functional thin film element according to claim 1, wherein the functional thin film element is formed from an organic compound in which at least one metal element and an organic molecule are bonded.   4. The functional thin film element according to claim 3, wherein the organic molecule includes a cyclic molecule.   4. The functional thin film element according to claim 3, wherein the organic molecule includes at least any cyclic molecule selected from a porphyrin ring, a phthalocyanine ring, a triphenylene ring, and a methene ring.   6. The functional thin film element according to claim 3, wherein the organic molecule has a molecular weight of 250 to 25,000. The ratio of the thickness d _f of the functional thin film layer to the thickness d _o of the organometallic complex layer (d _f / d _o) is 10 ⁰ <satisfy the relation of d _{f /} d _o <10 ⁵ The functional thin film element according to any one of claims 1 to 6. The thickness d _o of the organometallic complex layer, the functional thin film element according to any one of claims 1 to 7, characterized in that at 10nm or less.   The functional thin film element according to any one of claims 1 to 8, wherein the anode is formed of a material containing at least conductive nanoparticles and a polymer resin having optical transparency.   The functional thin film element according to claim 1, wherein at least one of the anode and the functional thin film is formed of a π-conjugated material.   The functional thin film element according to claim 10, wherein the π-conjugated material is a polymer material that is soluble in water or a solvent.   12. The functional thin film device according to claim 11, wherein the polymer material is at least one selected from doped polypyrrole, polyaniline, polythiophene, polyacetylene, polyisothianaphthene, and derivatives thereof. .   The functional thin film element according to claim 11, wherein the polymer material is at least one selected from polyethylene dioxythiophene, polypropylene oxide, and derivatives thereof.   The functional thin film element according to claim 1, wherein the substrate is formed of a polymer resin film having an average light transmittance of 80% or more in a visible light region.   The functional thin film element according to claim 12, wherein the in-plane birefringence Δn of the polymer resin film is 0.1 or less.   16. The polymer resin according to claim 14, wherein the polymer resin is one selected from polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polyether sulfone, and derivatives thereof. Functional thin film element.   On the substrate, a printing method is used to form an anode with a material including a π-conjugated polymer that is soluble in water or a solvent, or a conductive nanoparticle and a light-transmitting polymer resin. After forming the organometallic complex layer, a functional thin film is formed on the organometallic complex layer with a π-conjugated polymer, and a cathode is formed on the functional thin film using a printing method with a π-conjugated polymer. A method for producing a functional thin film element.   On the substrate, a cathode is formed by a printing method using a material including a π-conjugated polymer that is soluble in water or a solvent, or a conductive nanoparticle and a polymer resin having optical transparency, and the cathode is formed on the cathode. After forming a functional thin film with a π-conjugated polymer, an organometallic complex layer is formed on the functional thin film, and then an anode is formed on the organometallic complex layer with a π-conjugated polymer using a printing method. Forming a functional thin film element.   An article using a functional thin film element produced by using the method for producing a functional thin film element according to claim 17 or 18.   An article of either a display body or an illuminating body using the functional thin film element according to any one of claims 1 to 16.   A photovoltaic module using the functional thin film element according to any one of claims 1 to 16. A semiconductor module using the functional thin film element according to claim 1.

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