JP5335379B2 - Organic semiconductor material and organic electronic device using the same - Google Patents

Description

The present invention relates to an organic semiconductor that is excellent in stability such as oxidation resistance and solubility in an organic solvent, and is characterized by processability.

Organic thin-film transistors have been actively researched and developed because of the possibility of realizing inexpensive transistor products utilizing the light weight and flexibility that are the characteristics of organic materials. Organic semiconductor materials exist as thin films in organic transistors, but their characteristics are very important factors that influence the device manufacturing process and device performance.
In particular, many reports have been made on polycyclic aromatic compounds represented by pentacene, from the viewpoint of high mobility and stability of the compounds themselves. (Non-Patent Document 1)

Organic thin film transistor manufacturing methods can be broadly divided into dry processes, typically represented by vacuum deposition, and wet processes, typically represented by solution coating, and can achieve significant cost reductions. Preferably it can be adapted to the process. However, since the dry process is advantageous in terms of transistor performance, it is more preferable if there is a highly flexible material that can be applied to either material.

Under such circumstances, benzochalcogenobenzochalcogenophene derivatives have been disclosed as new organic semiconductor materials that can be applied to both wet and dry processes. (Patent Document 1, Non-Patent Document 2)
It was also reported that the visible ultraviolet absorption spectra of benzothienobenzothiophene and chrysene are similar. (Non Patent Literature 3)

International Publication WO 2006/077788 A1 "Hong Meng, Michael Bendikov, Gregory Mitchell, Roger Helgson, Fred Wudl, Zhenan Bao, Theo Siegrist, Christian Kloc, Cheng-Hs. 1090 Hideaki Ebata, Takafumi Izawa, Eigo Miyazaki, Kazuo Takamiya, Masaaki Ikeda, Hirokazu Kuwabara, Tatsuto Yui, “JourAm. 15732 Kazuo Takamiya, Tatsuya Yamamoto, Hideaki Ebata, Takafumi Izawa "Science and Technology of Advanced Materials" 2007, 8, p. 273

Since the visible ultraviolet absorption spectra of benzothienobenzothiophene and chrysene are very similar, it was thought that chrysene could be a new organic semiconductor material that can be applied to both wet and dry processes. However, the performance as an organic transistor with a material having a chrysene skeleton has been unknown so far. The inventors of the present invention tried to evaluate an organic transistor element using chrysene by vacuum deposition. However, the transistor response could not be observed. Therefore, even if it is impossible with chrysene alone, we think that transistor response can be obtained by adding various substituents, and newly synthesized chrysene derivatives, and repeated evaluation of the transistor characteristics, The present invention has been reached.

Pentacene, which is a typical organic semiconductor material, has low solubility in an organic solvent, and further has a problem in stability in a solution state. Accordingly, an object of the present invention is to provide an organic semiconductor material that has high solubility in an organic solvent and is stable even in a solution state, instead of pentacene.

Therefore, the present inventors have intensively studied to solve the above-mentioned problems, and as a result, the compound having a chrysene skeleton has overcome the instability of pentacene and is a novel organic transistor that exhibits high performance as an organic transistor. The present inventors have found that it is a semiconductor material and have completed the present invention. That is, the present invention has the following configuration.

That is, the first invention provides an organic semiconductor material having a chrysene skeleton represented by the following chemical formula [Chemical Formula 1].
[Chemical formula 1]

However, R ¹² from Substituent R ¹ in chemical formula [1] in each independently C androgenic atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted alkyl group Substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted carbonyl group, substituted or unsubstituted ester group, substituted or unsubstituted amide group, substituted Or unsubstituted imino group, substituted or unsubstituted sulfide group, substituted or unsubstituted sulfoxide group, substituted or unsubstituted sulfonyl group, substituted or unsubstituted silyl group, carboxyl group, hydroxyl group, nitro group, nitrile group among the mercapto group, at least one and Dressings containing from ^{R 1 R 12} simultaneously Except for two substituted or unsubstituted phenylethenyl groups.

Preferable examples of R ¹² from substituents R ¹ are full Tsu atom, an aryl group, a heterocyclic group, an alkyl group, an alkenyl group, an alkynyl group.

In the substituents R ¹ to R ¹² , the halogen atom is fluorine, chlorine, bromine or iodine, and a preferred example is a fluorine atom.

The aryl group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include a phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2-heptylphenyl group, and 3-heptylphenyl. Group, 4-heptylphenyl group, 2-octylphenyl group, 3-octylphenyl group, 4-octylphenyl group, 4-methoxyphenyl group, 4-fluorophenyl group, pentafluorophenyl group, 4- (trifluoromethyl) A phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, etc. are mentioned.

The heterocyclic group in the substituents R ¹ to R ¹² is not particularly limited, and is a 2-thienyl group, a 5- (1-heptyl) -2-thienyl group, a 2-benzothienyl group, a 5′-hexyleu 2,2 ′. -Bithieno-5-yl group, 2-furyl group, 1-methyl-2-pyrrolyl group, 2-pyridyl group, 2-bipyridyl group and the like.

The alkyl group in the substituents R ¹ to R ¹² is not particularly limited, and is a linear, branched, or cyclic alkyl group such as an n-butyl group, an n-pentyl group, an n-hexyl group, n -Heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, isopropyl group, tert-butyl group, cyclopentyl group, cyclohexyl group, adamantyl group , Phenylethyl group, (p-hexylphenyl) ethyl group, naphthylethyl group, biphenylethyl group, terphenylethyl group, trifluoromethyl group, perfluorooctyl group, perfluorododecyl group and the like.

The alkenyl group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include an ethenyl group, a methylethenyl group, a hexylethenyl group, a phenylethenyl group, a (o-hexylphenyl) ethenyl group, and a (m-hexylphenyl) ethenyl group. , (P-hexylphenyl) ethenyl group, (p-heptylphenyl) ethenyl group, (p-octylphenyl) ethenyl group, naphthylethenyl group, biphenylethenyl group, terphenylethenyl group, perfluorophenylethenyl group, etc. Can be mentioned.

The alkynyl group in the substituents R ¹ to R ¹² is not particularly limited. For example, ethynyl group, methyl ethynyl group, octyl ethynyl group, phenyl ethynyl group, (o-hexylphenyl) ethynyl group, (m-hexylphenyl) ethynyl Group, (p-hexylphenyl) ethynyl group, (p-heptylphenyl) ethynyl group, (p-octylphenyl) ethynyl group, naphthylethynyl group, biphenylethynyl group, terphenylethynyl group, perfluorophenylethynyl group, trimethylsilylethynyl Group, triethylsilylethynyl group, tripropylsilylethynyl group, triisopropylsilylethynyl group and the like.

The carbonyl group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include an aldehyde group, ethanone, ethanal, 1-propanone, 2-propanone, propanal, 1-octanone, and (p-octylphenyl) ethanone. Can be mentioned.

The amide group in the substituents R ¹ to R ¹² is not particularly limited, and for example, an acetamido group, a propylamide group, a butylamide group, an isobutylamide group, a pentylamide group, an isopentylamide group, a sec-pentylamide group, a tert- Examples include a pentylamide group, various heptylamide groups, various pentylamide groups, various octylamide groups, and the like.

The sulfide group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include a methyl sulfide group, an ethyl sulfide group, a propyl sulfide group, an isopropyl sulfide group, a butyl sulfide group, an isobutyl sulfide group, a sec-butyl sulfide group, a tert -Butyl sulfide group, various pentyl sulfide groups, various hexyl sulfide groups, various heptyl sulfide groups, various octyl sulfide groups, phenyl sulfide groups, o-hexyl phenyl sulfide groups, m-hexyl phenyl sulfide groups, p-hexyl phenyl sulfide groups, etc. Is mentioned.

The sulfoxide group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include a methyl sulfoxide group, an ethyl sulfoxide group, a propyl sulfoxide group, an isopropyl sulfoxide group, a butyl sulfoxide group, an isobutyl sulfoxide group, a sec-butyl sulfoxide group, and a tert. -Butyl sulfoxide group, various pentyl sulfoxide groups, various hexyl sulfoxide groups, various heptyl sulfoxide groups, various octyl sulfoxide groups, phenyl sulfoxide groups, o-hexyl phenyl sulfoxide groups, m-hexyl phenyl sulfoxide groups, p-hexyl phenyl sulfoxide groups, etc. Is mentioned.

The sulfonyl group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include a methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, isopropylsulfonyl group, butylsulfonyl group, isobutylsulfonyl group, sec-butylsulfonyl group, tert -Butylsulfonyl group, various pentylsulfonyl groups, various hexylsulfonyl groups, various heptylsulfonyl groups, various octylsulfonyl groups, phenylsulfonyl group, o-hexylphenylsulfonyl group, m-hexylphenylsulfonyl group, p-hexylphenylsulfonyl group, etc. Is mentioned.

The silyl group in the substituents R ¹ to R ¹² is not particularly limited, and examples thereof include a trimethylsilyl group, a triethylsilyl group, a tributylsilyl group, a triisobutylsilyl group, a tripropylsilyl group, a triisopropylsilyl group, and a trisec-butylsilyl group. And tritert-butylsilyl group.

Subsequently, the second invention is the organic semiconductor material according to the first invention, wherein R ² and R ⁸ in the chemical formula [Chemical Formula 1] are the same substituents other than hydrogen atoms.

Subsequently, a third invention is the organic semiconductor material according to the first invention, wherein R ⁶ and R ¹² in the chemical formula [Chemical Formula 1] are the same substituents other than hydrogen atoms.

A sixth invention is an organic electronic device comprising any one of the organic semiconductor materials of the first to fifth inventions, or a combination of any of the organic semiconductor materials.

The term “organic electronic device” as used herein refers to an electronic device that utilizes the electrical characteristics of the present compound, and specific examples include organic transistors, organic lasers, organic thin-film solar cells, and organic memories.

When the compound of the present invention is used in these organic electronic devices, purification such as removal of impurities is required for high purity, but the compound of the present invention can be obtained by liquid chromatography method, sublimation method, zone melting method. It can be purified by gel permeation chromatography, recrystallization, thermal washing, and the like.

Further, when the compound of the present invention is used in an organic electronic device, it is mainly used in the form of a thin film, and either a wet process or a dry process may be used as a method for forming the thin film. By dissolving the compound of the present invention in an organic solvent or the like, it can be applied to a wet process having great industrial merit.

Here, as the organic solvent, for example, known solvents such as dichloromethane, chloroform, chlorobenzene, cyclohexanol, toluene, xylene, nitrobenzene, methyl ethyl ketone, diglyme, and tetrahydrofuran can be used. In addition, when the compound of the present invention is dissolved in an organic solvent or the like, the temperature and pressure are not particularly limited, but the temperature for dissolution is preferably in the range of 0 to 200 ° C, more preferably in the range of 10 to 150 ° C. It is. Moreover, regarding the pressure to melt | dissolve, the range of 0.1-100 MPa is preferable, More preferably, it is the range of 0.1-10 MPa. Moreover, it is also possible to use something like supercritical carbon dioxide instead of the organic solvent.

The wet process here refers to a spin coating method, a dip coating method, a bar coating method, a spray coating method, an ink jet method, a screen printing method, a lithographic printing method, an intaglio printing method, a relief printing method, and the like. Can be used.
Furthermore, the dry process mentioned here indicates a vacuum deposition method, a sputtering method, a CVD method, a laser deposition method, a molecular beam epitaxial growth method, a vapor phase transport growth method, and the like, and these known methods can be used.

Examples of use of the organic electronic device using the compound of the present invention are shown in FIGS. FIG. 1 shows an example of use in a field effect transistor (hereinafter referred to as FET). FETs are used as switching elements and amplifying elements because of their characteristics. In addition to a low gate current, the structure is planar, so that fabrication and integration by a wet process are easy and a large area can be achieved. Here, although the compound of the present invention is mainly used as a p-type semiconductor, it may function as an n-type semiconductor depending on a substituent or a solvent.

FIG. 2 shows an example of use in an organic thin film solar cell. The co-deposited layer shown in FIG. 2 is a layer in which p-type and n-type are vapor-deposited together, and this layer is intended to facilitate separation by holes and electrons by sunlight.

In the first invention, an organic semiconductor material that is easy to manufacture in an organic semiconductor electronic device that can be easily handled in the atmosphere and can be adapted to both a dry process and a wet process by changing the type of substituent. Can be provided.

In the second invention, by making the substituents the same, the synthesis process is facilitated. In particular, by making the same substituents R ² and R ⁸ , the material is suitable for the dry process and has excellent transistor characteristics. Can be provided.

In 3rd invention, the synthetic | combination process becomes easy by making a substituent into the same. In particular, by using the same substituent for R ⁶ and R ¹² , a material that is suitable for a wet process and excellent in transistor characteristics can be provided.

In the fourth invention, the organic semiconductor material of the first invention to the third invention can be used for an organic electronic device.

A typical example is shown below.

An example of the synthesis process of the chemical formula [Chemical Formula 1] of the present invention is shown in [Synthesis Route], and the details will be described below. However, the synthesis method described below is not particularly limited, and can be synthesized by combining known reactions. Incidentally, denoted A, B, the sign of · · · H for each compound.
[Synthetic route]

The present invention will be described in more detail using the above [synthesis route]. (Synthesis of Compound F )
(1) Synthesis of Compound A Under a nitrogen atmosphere, 103 g (455 mmol) of 4-bromocinnamic acid, 4.5 g (46 mmol) of sulfuric acid, and 1 L of methanol were added to a 1 LGL flask with a condenser, and stirred at 60 ° C. for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, 1.2 L of water was added, and the crystals were filtered. The obtained crude crystals were recrystallized to obtain Compound A.

(2) Synthesis of Compound B Under a nitrogen atmosphere, 29 g (1058 mmol) of aluminum, 600 mL of methanol, and 55 g (216 mmol) of iodine were added to a 3LGL flask with a cooling tube, and stirred at room temperature for 1 hour. After cooling to 0 ° C. or lower, 104 g (432 mmol) of compound A and 600 mL of methanol were added, and 56 g (371 mmol) of samarium was then added. The mixture was slowly returned to room temperature and stirred at room temperature for 15 hours. After completion of the reaction, 800 mL of toluene was added and filtered through Celite. The filtrate was washed with dilute hydrochloric acid, aqueous sodium bicarbonate, and brine, dried over magnesium sulfate, and concentrated under reduced pressure. The resulting crude crystals were purified by column chromatography to obtain compound B.

(3) Synthesis of Compound C Under a nitrogen atmosphere, 32 g (66 mmol) of Compound B and 250 mL of trifluoromethanesulfonic acid were added to a 1 LGL flask with a cooling tube, and the mixture was stirred at 40 ° C. for 17 hours. After completion of the reaction, the reaction mixture was cooled to 5 ° C., 300 mL of water was added dropwise, and the crystals were filtered. The resulting crude crystals were purified by column chromatography to obtain compound C.

(4) Synthesis of Compound D Under a nitrogen atmosphere, 9.5 g (23 mmol) of Compound C , 760 mL of isopropanol, 3.1 g (84 mmol) of sodium borohydride, and 30 mL of water were added to a 2 LGL flask with a cooling tube. Stir for hours. After completion of the reaction, the reaction mixture was cooled to 10 ° C. and 1 L of water was added. The crystals were filtered, and the resulting crude crystals of compound D were used for the next reaction without purification.

(5) Synthesis of Compound E Under a nitrogen atmosphere, 8.6 g (20 mmol) of Compound D, 3.9 g (20 mmol) of paratoluenesulfonic acid monohydrate, and 430 mL of toluene were added to a 1 LGL flask with a cooling tube at 110 ° C. Stir for 24 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, and 200 mL of water and 200 mL of n-heptane were added and filtered. The obtained crude crystals were purified by recrystallization after column chromatography to obtain Compound E.

(6) Synthesis of Compound F In a nitrogen atmosphere with a cooling tube, Compound E 500 mg (1.3 mmol), phenylboronic acid 470 mg (3.9 mmol), tetrakistriphenylphosphine palladium 30 mg (0.03 mmol), carbonic acid 1070 mg (7.8 mmol) of potassium, 10 mL of toluene and 3 mL of water were added, and the mixture was stirred at 80 ° C. for 16 hours. After completion of the reaction, the mixture was cooled to room temperature, water was added, and the crystals were filtered. The obtained crude crystals were purified by heat washing to obtain Compound F. The mass spectrum of Compound F is shown in FIG.

(7) Synthesis of Compound G Under a nitrogen atmosphere, 1.00 g (4.4 mmol) of chrysene and 250 mL of chloroform were added to a 500 mL GL flask with a cooling tube and heated to 60 ° C., followed by 1.8 g (11.0 mmol) of bromine. And stirred at 60 ° C. for 24 hours. After completion of the reaction, an aqueous sodium hydrogen sulfate solution was added, and the crystals were filtered. The obtained crude crystals were purified by recrystallization to obtain compound G.

(8) Synthesis of Compound H Under a nitrogen atmosphere, 130 mg (5.4 mmol) of metal magnesium and 2.6 mL of tetrahydrofuran were added to a 30 mLGL flask with a cooling tube, and then 1000 mg (5.2 mmol) of 1-bromooctane was added dropwise. The Grignard reagent was prepared by stirring at 40 ° C. for 1 hour.
Under a nitrogen atmosphere, 500 mg (1.3 mmol) of Compound H , 28 mg (0.05 mmol) of diphenylphosphinopropanedichloronickel and 8 mL of tetrahydrofuran were added to a 30 mL GL flask, and cooled to 0 ° C. Subsequently, the previously prepared Grignard reagent of 1-bromooctane was added and stirred at 0 ° C. for 4 hours. After completion of the reaction, dilute hydrochloric acid and toluene were added, and the mixture was warmed to room temperature. The organic layer was washed with aqueous sodium bicarbonate and brine, dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude crystals were purified by recrystallization after performing column chromatography to obtain Compound H. The NMR spectrum of Compound H is shown in FIGS.

Fabrication of organic thin film transistor (single crystal attachment)
Using the 2,8-diphenylchrysene (compound F ) produced in Example 1, a thin film device having the structure shown in FIG. 1 was produced. Specifically, a silicon wafer on which a thermal oxide film having a thickness of 210 nm is formed is spin-coated with polymethyl methacrylate (PMMA) in toluene (3 wt%) in the air (rotation speed: 2000 rpm, 30 sec), and a nitrogen atmosphere A PMMA insulating film was manufactured by performing heat treatment at 70 ° C. overnight and subsequently at 100 ° C. for 3 hours. A thin single crystal of 2,8-diphenylchrysene (compound F 2 ) was pasted on this, and a gold paste was applied to both ends of the crystal to produce a field effect transistor element and evaluated.
As a result, the field effect mobility was 0.91 cm ² / V · s, and the On / Off current ratio was 10 ³ .

Fabrication of organic thin-film transistors (evaporation)
2,8-diphenylchrysene (compound F ) is vacuum-deposited on a silicon wafer on which a thermal oxide film having a thickness of 210 nm is formed at a substrate temperature of 60 ° C., and gold serving as a source / drain electrode is electron-electronized thereon. A TOP contact type element was fabricated and evaluated by depositing 80 nm by the beam method.
As a result, the field effect mobility is ^{4.1 × 10 -2 cm 2 / V} · s, On / Off current ratio was 10 ^5.

Fabrication of organic thin film transistor (coating: cast)
A chloroform solution (0.4 wt%) of 6,12-dioctylchrysene (compound H 2 ) was cast in the air on a silicon wafer on which a thermal oxide film having a thickness of 210 nm was formed, to produce a thin film. On top of that, gold was deposited as a source / drain electrode by 80 nm by an electron beam method, and a TOP contact type device was fabricated and evaluated.
As a result, the field-effect mobility, at ^{1.2 × 10 -3 cm 2 / V} · s, On / Off current ratio was 10 ^4.

(Comparative example)
Instead of the compound of the present invention, the following pentacene (compound I ) was used as a comparative compound, and a comparative element was produced in the same manner as in the above example.
As a result, in the element to which the single crystal of pentacene (Compound I ) was attached, the field effect mobility was 0.27 cm ² / V · s, and the On / Off current ratio was 10 ³ .
In the element deposited with pentacene, the field effect mobility was 0.15 cm ² / V · s, and the On / Off current ratio was 10 ⁴ . In the device by coating, the sample solution could not be prepared due to poor solubility of pentacene. In addition, the 2,9-dioctylpentacene (compound J ) shown below, which is a pentacene derivative, rapidly oxidized in the atmosphere after adjusting the chloroform solution (0.4 wt%), and thus a device was manufactured. It was difficult.

7 and 8, respectively, immediately after dissolving pentacene (compound I ) and 6,12-dioctylchrysene (compound H ) in an organic solvent 1,1,2,2-tetrachloroethane, 24 hours and 48 hours, respectively. The time-dependent change of visible UV absorption spectrum afterwards is shown. From FIG. 7, the spectrum shape of pentacene (compound I ) changes greatly due to oxidative degradation immediately after solution preparation and after 24 hours. On the other hand, as shown in FIG. 8, 6,12-dioctylchrysene (Compound H 2 ) has the same spectral shape from immediately after the preparation of the solution to 48 hours later, and is very stable in the solution state.

The MS spectrum was measured with a GCMS-QP2010 manufactured by Shimadzu Corporation by an EI ionization method using a direct sample introduction apparatus DI-2010.
The NMR spectrum was measured with VARIAN Mercury Plus 400 MHz (deuterated chloroform solvent) manufactured by VARIAN.
The visible ultraviolet absorption spectrum was measured with a Hitachi U-3310 type spectrophotometer.

The organic transistor using the compound of the present invention can be applied to various manufacturing processes such as single crystal bonding method, vacuum deposition method and coating method. A thin film can be formed therein. Therefore, it is an organic semiconductor that is very useful in industry, and is expected to be widely used in this field in the future.

FETs using organic semiconductors Organic thin film solar cell device Thin film device Mass spectrum of Compound F ¹ H-NMR spectrum of Compound H ¹³ C-NMR spectrum of Compound H Temporal change of visible ultraviolet light absorption spectrum of pentacene (compound I ) Temporal change of visible ultraviolet absorption spectrum of Compound H

Explanation of symbols

1 FETs using organic semiconductors
2 Organic semiconductor 3 Insulating film
4 gate 41 gate insulating film 5 drain 6 source 7 emitter 8 collector 9 base 10 substrate (plastic) 11 electrode 12 n-type semiconductor 13 p-type semiconductor 14 co-deposition layer 15 ITO (Indium Tin Oxide)
20 Thin Film Device 21 Source 22 Drain
23 PMMA Dielectric Layer 24 Si / SiO ₂ Substrate
25 Gate 26 Organic Single Crystal

Claims (3)

An organic semiconductor material represented by the following chemical formula [Chemical Formula 1], wherein R ² and R ⁸ in the chemical formula [Chemical Formula 1] are each independently a substituted or unsubstituted aryl group. .
[Chemical formula 1]
The substituents R ¹ to R ¹² in the chemical formula [Chemical Formula 1] are hydrogen atoms except for R ² and R ⁸ .
The aryl group is a phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2-heptylphenyl group, 3-heptylphenyl group, 4-heptylphenyl group, 2-octylphenyl group. Of 3-octylphenyl group, 4-octylphenyl group, 4-methoxyphenyl group, 4-fluorophenyl group, pentafluorophenyl group, 4- (trifluoromethyl) phenyl group, naphthyl group, biphenyl group, terphenyl group Either. ^2. The organic semiconductor material according to claim 1, wherein R ² and R ⁸ in the chemical formula [Chemical Formula 1] are the same substituted or unsubstituted aryl group.   An organic electronic device comprising a combination of the organic semiconductor material according to claim 1 or 2 or a plurality of any of the organic semiconductor materials.