JP6120271B2 - Organic semiconductor composition - Google Patents

Description

  The present invention relates to an organic semiconductor composition.

  The component of the organic semiconductor that can be applied by conventional solvent-solubility (can be converted into ink) to form a thin film has been one component (Patent Documents 1 to 3). This is because it was considered that one component is necessary to realize high carrier mobility.

JP2012-031159 JP2011-236299 JP2011-236143

  If the organic semiconductor component is a single component, the solution viscosity as a coating condition and the thermal stability after coating are determined by the solubility of the component in a solvent. Was needed.

The present invention provides the following organic semiconductor composition.
Item 1. An organic semiconductor composition, wherein molecules are arranged so as to form a layered structure in a mixed system of a plurality of π electron condensed ring compounds having the same π electron condensed ring and substituents having different chain lengths.
Item 2. Item 2. The organic semiconductor composition according to Item 1, wherein the carrier mobility is 10 ^-2 cm ² V ^-1 s ^-1 or more.
Item 3. Item 3. The organic semiconductor composition according to Item 1 or 2, wherein at least one of the π-electron condensed ring compounds constituting the organic semiconductor composition is a liquid crystal phase having a layered structure at a specific temperature or a plastic phase.
Item 4. Item 4. The organic semiconductor composition according to any one of Items 1 to 3, wherein at least one of the substituents of the π electron condensed ring compound has a photopolymerizable functional group.
Item 5. Item 5. The organic semiconductor composition according to any one of Items 1 to 4, wherein the π-electron condensed ring compound has at least one substituent selected from the group consisting of alkanes and oxyalkanes.
Item 6. Item 6. The organic semiconductor composition according to any one of Items 1 to 5, wherein the π-electron condensed ring compound has one or two long chain groups having a photopolymerizable functional group at a terminal thereof.

  In the field of so-called printed electronics in which a semiconductor thin film electronic device is formed on a flexible polymer substrate, there is a research using an organic semiconductor made of an organic material. In the present invention, a new practical organic semiconductor composition capable of adjusting practicality such as temperature characteristics and various conditions during application (solution viscosity, etc.) in an organic semiconductor that is soluble in solvent and strong in self-organization is the same as This is achieved by a mixed system of a plurality of π electron condensed ring compounds having substituents having different chain lengths from the electron condensed ring.

As a conventional organic semiconductor material for forming a coating-type thin film, only a single component material has been studied because a single crystal having no electronic space fluctuation is preferable from the viewpoint of electron transport. On the other hand, if the liquid crystal phase is a thermodynamically equivalent phase, liquid crystal compounds are mixed at a molecular level with an arbitrary composition ratio even if there are a plurality of types (liquid crystal phase miscibility). By utilizing this property, an organic semiconductor composition in which organic semiconductors having liquid crystallinity are mixed at an arbitrary composition ratio and dispersed at a molecular level can be obtained. In particular, homologous series compounds having the same π-electron skeleton and different chain lengths of long chain portions such as alkyl groups are expected to exhibit good miscibility. By utilizing this property, it is expected that by changing the composition ratio, the packing of the π-electron skeletons can be controlled, and the structure in which charges move can be made more efficient. Based on this new idea, we measured the semiconductor properties of organic semiconductor compositions in the same family, and showed high-speed carrier mobility of 10 ^-2 cm ² V ^-1 s ^-1 or more.

9TNAT9-3TNAT3 binary system phase diagram Temperature dependence of hole mobility in 9TNAT9-3TNAT3 (1: 1 molar ratio) mixed system Temperature dependence of Hall mobility in 3TNAT3

  The present invention relates to an organic semiconductor composition characterized in that molecules are arranged so as to form a layered structure in a mixed system of a plurality of π electron condensed ring compounds having the same π electron condensed ring and substituents having different chain lengths. I will provide a.

  The organic semiconductor composition of the present invention has a plurality of π-electron condensed ring compounds, and each compound has a common π-electron condensed ring and has different side chain lengths.

  As the π-electron condensed ring compound, all known compounds can be used, and are not particularly limited. However, as a preferable compound, one or two or more substituents, preferably 1 to 6, are added to the π-electron condensed ring. Preferably it has 2-6 pieces.

  The structure or partial structure of the π electron condensed ring included in the π electron condensed ring compound is shown below.

(In the formula, n represents an integer of 3 or more, for example, an integer of 3 to 10. A represents a divalent crosslinking group.)
The π electron condensed ring compound having the above “partial structure” includes a case where two or more π electron condensed rings are connected by a single bond or form a condensed ring. For example, bipyridyl in which two pyridines are linked by a single bond, and benzofuran in which benzene and furan are condensed are all included in the π-electron condensed ring of the π-electron condensed ring compound.

  The π electron fused ring compound of the present invention has one or more substituents. The number of substituents is preferably 1 to 6, more preferably 2 to 6, further preferably 2 to 3, particularly 2. The π electron condensed ring compound of the present invention is preferably one that forms a rod-like liquid crystal. In the case of constituting a rod-like liquid crystal, the number of substituents of the π electron condensed ring compound is 1 or 2, preferably 2. In the case of having two substituents, the direction of the substituent is typically at an angle of 180 °, but there are two such as the 1,3-position of the 5-membered ring and the 1,3-position of the 6-membered ring. If the angle formed by the substituent is 120 to 180 °, or 144 to 180 °, it is included in the “rod-like” liquid crystal. When the naphthalene ring has a substituent at the 1,5-position as well as the 1,5-position, the two substituents are not on the same straight line but form an angle of 180 °.

  The at least one π-electron condensed ring compound of the present invention preferably forms a liquid crystal phase having a layered structure or a plastic phase at a specific temperature. Preferably, all the π-electron condensed ring compounds form a liquid crystal phase having a layered structure or a plastic phase at a specific temperature.

  Although it does not specifically limit as a bivalent crosslinking group represented by A, For example, the following groups can be mentioned.

(In the formula, m represents an integer of 1 to 4. X represents a methyl group, an ethyl group, a fluorine atom or a chlorine atom.)
One or two or more of the above-mentioned bridging groups may be contained in the substituent, and two or more π-electron condensed ring portions may be connected to constitute one π-electron condensed ring as a whole. Good.

  Examples of the substituent of the π electron condensed ring compound of the present invention include alkyl, aryl, heteroaryl, aralkyl, alkenyl, alkynyl, alkyloxy, aryloxy, heteroaryloxy, aralkyloxy, alkenyloxy, alkynyloxy, alkyloxycarbonyl, Aryloxycarbonyl, heteroaryloxycarbonyl, aralkyloxycarbonyl, alkenyloxycarbonyl, alkynyloxycarbonyl, alkyloxycarbonyloxy, aryloxycarbonyloxy, heteroaryloxycarbonyloxy, aralkyloxycarbonyloxy, alkyloxycarbonylamino, aryloxycarbonyl Amino, heteroaryloxycarbonylamino, aralkyloxycarbonylamino, etc. And the like.

  Examples of the alkyl group include 3 to 22 carbon atoms such as propyl, butyl, isobutyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl, eicosyl and docosyl. Examples thereof include a linear or branched alkyl group.

  Examples of the alkenyl group include allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, 2-ethylhexenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, hexadecenyl, octadecenyl, eicosenyl, dococenyl and the like. Examples thereof include a chain or branched alkenyl group.

  The alkynyl group is a straight chain having 3 to 22 carbon atoms such as propargyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, 2-ethylhexynyl, nonynyl, decynyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, hexadecynyl, octadecynyl, eicosinyl, docosinyl Or a branched alkynyl group is mentioned.

  The aryl group means a monocyclic or polycyclic group composed of a 5- or 6-membered aromatic hydrocarbon ring. Specific examples include phenyl, naphthyl, fluorenyl, anthryl, biphenylyl, tetrahydronaphthyl, chromanyl, 2 , 3-dihydro-1,4-dioxanaphthalenyl, indanyl and phenanthryl.

  Aralkyl groups include benzyl, naphthylmethyl, fluorenylmethyl, anthrylmethyl, biphenylylmethyl, tetrahydronaphthylmethyl, chromanylmethyl, 2,3-dihydro-1,4-dioxanaphthalenylmethyl, indanyl Methyl and phenanthrylmethyl, phenethyl, naphthylethyl, fluorenylethyl, anthrylethyl, biphenylylethyl, tetrahydronaphthylethyl, chromanylethyl, 2,3-dihydro-1,4-dioxanaphthalenylethyl, And indanylethyl and phenanthrylethyl.

  Heteroaryl group means a monocyclic or polycyclic group consisting of a 5- or 6-membered aromatic ring containing 1 to 3 heteroatoms selected from N, O and S. In some cases, at least one ring may be an aromatic ring. Specific examples include furyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolyl, quinolyl, isoquinolyl, benzo [b] thienyl, benzimidazolyl, benzothiazolyl, benzoxazolyl And the like.

  Alkyloxy includes (alkyl) oxy (where “alkyl” is as defined above).

  Aryloxy includes (aryl) oxy (where “aryl” is as defined above).

  Heteroaryloxy includes (heteroaryl) oxy (where “heteroaryl” is as defined above).

  Aralkyloxy includes (aralkyl) oxy (wherein “aralkyl” is as defined above).

  Alkenyloxy includes (alkenyl) oxy (wherein “alkenyl” is as defined above).

  Alkynyloxy includes (alkynyl) oxy (wherein “alkynyl” is as defined above).

  Alkyloxycarbonyl includes (alkyl) oxycarbonyl (wherein “alkyl” is as defined above).

  Aryloxycarbonyl includes (aryl) oxycarbonyl (where “aryl” is as defined above).

  Heteroaryloxycarbonyl includes (heteroaryl) oxycarbonyl (where “heteroaryl” is as defined above).

  Aralkyloxycarbonyl includes (aralkyl) oxycarbonyl (wherein “aralkyl” is as defined above).

  Alkenyloxycarbonyl includes (alkenyl) oxycarbonyl (wherein “alkenyl” is as defined above).

  Alkynyloxycarbonyl includes (alkynyl) oxycarbonyl (wherein “alkynyl” is as defined above).

  Alkyloxycarbonyloxy includes (alkyl) oxycarbonyloxy (where “alkyl” is as defined above).

  Aryloxycarbonyloxy includes (aryl) oxycarbonyloxy (where “aryl” is as defined above).

  Heteroaryloxycarbonyloxy includes (heteroaryl) oxycarbonyloxy (where “heteroaryl” is as defined above).

  Aralkyloxycarbonyloxy includes (aralkyl) oxycarbonyloxy (where “aralkyl” is as defined above).

  Examples of alkenyloxycarbonyloxy include (alkenyl) oxycarbonyloxy (where “alkenyl” is as defined above).

  Alkynyloxycarbonyloxy includes (alkynyl) oxycarbonyloxy (where “alkynyl” is as defined above).

  Alkyloxycarbonylamino includes (alkyl) oxycarbonylamino (where “alkyl” is as defined above).

  Aryloxycarbonylamino includes (aryl) oxycarbonylamino where “aryl” is as defined above.

  Heteroaryloxycarbonylamino includes (heteroaryl) oxycarbonylamino where “heteroaryl” is as defined above.

  Aralkyloxycarbonylamino includes (aralkyl) oxycarbonylamino (where “aralkyl” is as defined above).

  Alkenyloxycarbonylamino includes (alkenyl) oxycarbonylamino (wherein “alkenyl” is as defined above).

  Alkynyloxycarbonylamino includes (alkynyl) oxycarbonylamino (wherein “alkynyl” is as defined above).

The substituent of the present invention may be one in which two or more substituents are linked by a crosslinking group (A). For example,-(alkyl)-(crosslinking group)-(alkyl),
-(Alkenyl)-(crosslinking group)-(alkenyl),
-(Alkynyl)-(crosslinking group)-(alkynyl),
-(Aryl)-(bridging group)-(aryl),
-(Heteroaryl)-(bridging group)-(heteroaryl),
-(Aralkyl)-(crosslinking group)-(aralkyl),
-(Aryl)-(bridging group)-(aryl)-(bridging group)-(aryl),
-(Alkyl)-(crosslinking group)-(aryl)-(crosslinking group)-(alkyl),
-(Alkyl)-(crosslinking group)-(alkyl)-(crosslinking group)-(alkyl),
-(Alkyl)-(bridging group)-(heteroaryl)-(bridging group)-(alkyl),
Is mentioned. Although the above shows the case where the number of crosslinking groups is one or two, the number of crosslinking groups may be 3 or more.

  In the above, the terminal substituent is a monovalent group such as alkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl, etc., but the non-terminal substituent is a divalent group, and therefore these substituents Are sometimes referred to herein as alkyl, alkenyl, alkynyl, aryl, heteroaryl, and aralkyl moieties. An alkyl moiety, an alkenyl moiety, an alkynyl moiety, an aryl moiety, a heteroaryl moiety, and an aralkyl moiety are groups in which one hydrogen atom has been removed from the corresponding alkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl.

Preferable examples of the rod-like / long-chain substituents (usually 1 or 2 or more, preferably 2) of the π-electron condensed ring compound are shown below.
-OR, -R, -COOR, -OOCR, -OOCOR, -CX = CY-COOR, -NHR, -NHCOR, -COSR, -NR 2, -SR, -OCOSR, -COR
(Wherein R represents alkyl having 3 to 22 carbon atoms, preferably 6 to 20 carbon atoms)
The π-electron condensed ring compound of the present invention can have other substituents in the π-electron condensed ring in addition to the rod-like / long chain substituent. Other substituents include —C≡N, —NO ₂ , halogen atoms (Cl, F, Br, I), OH, N ₃ , NH ₂ , CF ₃ , CH ₃ , COCH ₃ , NHCOCH ₃ , NHCH _3. , NH (CH ₃ ) _{2 and the} like.

The organic semiconductor composition of the present invention contains two or more kinds of π-electron condensed ring compounds, and the length of the side chain (side chain main chain) of the compound is 2 atoms or more, preferably 3 atoms or more, for example, 3 to 15 Atoms, preferably 4 to 12 atoms different. Here, when the side chain is a propyl group (C3) and a nonyl group (C9), the number of carbon atoms is different by 6 and thus the length is different by 6 atoms. Similarly, since the number of atoms of the OCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₃ group is 9 and the number of atoms of the-(OCH ₂ CH ₂ ) ₅ -OCH ₂ CH ₃ group is 18, these substituents Π-electron fused ring compounds having a difference of 9 atoms in length. Thus, the length of the substituent is determined by the number of atoms constituting the main chain, and by comparing the number of atoms of the main chain, the length of the side chain between two or more π-electron condensed ring compounds can be calculated. You can determine the difference.

  In the present invention, in the case of an organic semiconductor composition containing two π-electron condensed ring compounds, the length of the main chain of the side chain is 2 atoms or more, preferably 3 atoms or more, such as 3 to 15 atoms, preferably When 4 to 12 atoms are different and three or more π-electron condensed ring compounds are included, the length of the main chain of the side chain differs between the two arbitrary compounds by the number of atoms described above. In addition, when one π-electron condensed ring compound has a plurality of substituents having 3 or more atoms, the lengths are preferably the same. For example, regardless of whether the π-electron condensed ring compound has a substituent such as a halogen atom, a nitro group, an amino group, a cyano group, or a methoxy group, all the substituents having an atomic length of 4 or more Are the same. In other words, one π-electron condensed ring compound does not have a substituent of 10 and 15 atoms in length.

  The analog compound of the present invention preferably has a photopolymerizable functional group, and more specifically, has the following structure.

(Wherein alkyl represents an alkylene group, alkenyl represents an alkenylene group, and alkynyl represents an alkynylene group. Ring represents a π-electron condensed ring.)
In the organic semiconductor composition of the present invention, the molar ratio of the two or more π-electron condensed ring compounds is preferably 1:10 to 10: 1, more preferably 1: 5 to 5 in terms of the molar ratio of any two compounds. : 1, more preferably 1: 3 to 3: 1.

The carrier mobility of the organic semiconductor composition used in the present invention is 1.0 × 10 ⁻² cm ² V ⁻¹ s ⁻¹ or more, preferably 1.0 × 10 ^{−2 to} 1.0 × 10 ² cm ^2. V ⁻¹ s ⁻¹ .

Hereinafter, the present invention will be described in more detail based on examples and comparative examples.
Reference example 1
9TNAT9 and 3TNAT3 were synthesized as follows.

9TNAT9 was synthesized and purified based on the literature (Advanced Materials, 2007, Vol. 19, p1864). Specifically, 2-Nonylthiophene (40.0 mmol) and dehydrated THF (20 mL) were put into a 200 mL reactor subjected to argon gas replacement, and cooled to −50 ° C. with a dry ice-acetone bath. While flowing argon gas, n-butyllithium solution (15.4 mL of a 2.6 mol / L hexane solution, 40.0 m mol) was gradually added dropwise while maintaining the internal temperature of -40 to -50 ° C. All the n-butyllithium solutions were added dropwise and then stirred at room temperature for 4 hours. After cooling to -50 ° C in a dry ice-acetone bath, Trimethylborate (15.6 mL, 140 mmol) was slowly added to the reaction vessel while maintaining the internal temperature of -40 to -50 ° C, and further stirred at room temperature for 16 hours. . 2,6-Dibromonaphthalene (10.0 mmol), dehydrated 1,2-Dimethoxyethane (65 mL) and Pd (PPh3) 4 (0.0418 mmol) were sequentially added, and 2M-Na2CO3aq (10.0 mL, 20.0 mmol) was added dropwise. The reaction was performed at an internal temperature of about 69 ° C. for 23 hours under an argon atmosphere.
The reaction mass was discharged into 300 g of ice water (1: 1), stirred for 30 minutes, filtered, washed with water and air dried to obtain 2.62 g (81.9%) of a crude product. Sludge the air-dried product with Chloroform (300 mL) and wash with Hexane (150 mL). Purification by column chromatography (silica gel, Hot THF, Rf = 0.83) gave the desired product. Furthermore, it recrystallized with Acetone (1900 mL). White crystals, 46% yield. ¹ H-NMR δ _H (CDCl ₃ , TMS, 500 MHz) 0.89 (t, 6H), 1.34 (m, 24H), 1.72 (m, 4H), 2.84 (t, 4H), 6.79 (d, 2H), 7.25 (d, 2H), 7.70 (dd, 2H), 7.79 (d, 2H), 7.94 (s, 2H)
3TNAT3 was similarly prepared using 2-propylthiophene as the starting material. Pale yellowish white crystal, yield 66%), ¹ H-NMR δ _H (CDCl ₃ , TMS, 500 MHz) 1.02 (t, 6H), 1.76 (m, 4H), 2.83 (t, 4H), 6.79 (d , 2H), 7.25 (d, 2H), 7.70 (dd, 2H), 7.79 (d, 2H), 7.93 (s, 2H)

Example 1
(Preparation of mixed system and thermal phase transition)
9TNAT9 and 3TNAT3 were weighed to a molar ratio of 1: 1, and a methylene chloride solution was prepared and mixed.

  The mixed solution was used as a mixture sample by evaporating the solvent under reduced pressure. FIG. 1 shows a two-component phase diagram of 9TNAT9: 3TNAT3. 3TNAT3 is a compound having a phase transition at 79 ° C and 205 ° C, and 9TNAT9 is a compound having a phase transition at 101 ° C, 176 ° C, and 177 ° C. It was found that in the 1: 1 mixture system, the low temperature side intermediate phase showing the high carrier mobility of 9TNAT9 was maintained. These trends were the same for the compositions of 9TNAT9: 3TNAT3 = 3: 1 and 1: 3 (molar ratio).

(Carrier mobility of mixed system)
For the mixed system 9TNAT9: 3TNAT3 = 1: 1 (molar ratio) prepared previously, drift carrier mobility was measured by a time-of-flight measurement method at an intermediate phase temperature of 175 to 30 ° C. (for example, Journal of Materials Chemistry, 2007). Drift carrier mobility measurement can be performed as described in Year 17, Volume 17, p2607). Independence of the applied voltage, which is a typical property of liquid crystal semiconductors, was confirmed. FIG. 2 shows the temperature dependence of the hole mobility of 9TNAT9: 3TNAT3 = 1: 1 (molar ratio). It has been reported that the sample of 9TNAT9 single composition has 7.5 × 10 ⁻² cm ² V ⁻¹ s ⁻¹ at the same temperature and shows almost no temperature dependence. In this composition, it was found that the hole mobility was 3-5 × 10 ⁻² cm ² V ⁻¹ s ⁻¹ in a wide temperature range (FIG. 2). In the case of 3TNAT3 single composition sample, the temperature dependence is almost not shown, and it is about 7 x 10 ^-2 cm ² V ^-1 s ^-1 (Fig. 3). I found out. This suggests that 3TNAT3 molecules are dispersed between the layers of 9TNAT9 molecules oriented in a layered structure, and that the layer structure is very similar to that of charge transfer before mixing.

  The organic semiconductor composition of the present invention is effective for use and application to semiconductor thin film devices such as hybrid thin film transistors and organic thin film solar cells.

Claims (2)

An organic semiconductor composition characterized in that molecules are arranged so as to form a layered structure in a mixed system of a plurality of π electron condensed ring compounds having the same π electron condensed ring and substituents having different chain lengths ,
An organic semiconductor composition, wherein the plurality of π-electron condensed ring compounds are 9TNAT9 and 3TNAT3 represented by the following formula .
^2. The organic semiconductor composition according to claim 1, wherein the carrier mobility is 10 ⁻² cm ² V ⁻¹ s ⁻¹ or more.