JPH02218716A - Organic semiconductor and production thereof - Google Patents

Abstract

PURPOSE:To obtain an organic semiconductor, having specific recurring units and useful as electrode and display materials by carrying out electrolytic polymerization of a naphthalene compound having 2 thiophene rings and doping the resultant polymer with anions. CONSTITUTION:The objective semiconductor obtained by carrying out electrolytic polymerization of a naphthalene compound, expressed by formula I (thienyl groups are present on the same benzene ring or different benzene rings) and having 2 thiophene rings and doping the resultant polymer consisting of recurring units expressed by formula II with anions (preferably tetrafluoroborate ions, perchlorade ions, hexafluorophosphate ions, hexafluoroarsenate ions, iodide ions, bromide ions, chloride ions, fluoride ions, sulfate ions, hydrogensulfate ions, trifluoroacetate ions or p-toluenesulfonate ions).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an organic semiconductor comprising a novel thiophene polymer.

BACKGROUND OF THE INVENTION In recent years, various types of industrial equipment have become increasingly electronic, making it possible to downsize and improve the performance of the equipment. The growth of industries such as semiconductors, integrated circuits, and LSI has contributed significantly to this background, and it is predicted that the scope of use of electronic materials will continue to expand and demand will continue to increase.

In this situation, the development of new semiconductors has become an important issue, and research is being actively conducted on organic materials in addition to inorganic materials. Among organic materials, polymeric materials have excellent moldability, plasticity, and flexibility. Due to its excellent properties, polymer semiconductors are expected to be particularly widely used, and much research is being carried out.

Until now, polymer semiconductors have been made by adding electron acceptors to polymers such as polyacetylene and polyphenylene to give them semiconductor properties [Journal of the American Chemical Society (J, Am
, Chen+, Soc,) Volume 100, No. 1013
Page (1978), Synthetic Metal (Sy
ntli, Met, ) Volume 1, Page 307 (1
980)] and anion-doped polythiophene [Japanese Journal of Applied Physics (Jpn, J, of Appl, Phys.
s, ) Volume 22, page 412 (1983) Ko,
Poly[di(2-thienyl)biphenyl] [Macromolecular hemi-(Makromol, Chem,
) Volume 189, Page 1755 (1988)] are known.

However, these organic semiconductors generally lack stability, which limits their range of use, and
When these materials are used as electrode materials, although it is easy to dope them with anions, it is extremely difficult to dope them with cations, and even if they can be doped, their stability is poor. Furthermore, as a display material, the color tones at the time of color development are limited, which limits the scope of its use.

Polyacetylene is susceptible to the action of oxygen and is unstable in the air, which poses a practical problem. Furthermore, although polyphenylene has excellent stability, it is difficult to mold, like polyacetylene. Polythiophene has the characteristic that a doped polymer can be easily obtained on the electrode surface by electrolytic polymerization, but as an electrochromic display material, it could only produce two color tones, blue and red. Poly[di(2-thienyl)biphenyl] improved this point and was able to produce green and yellow tones, but was unable to produce anything else. However, although these polythiophene and poly[di(2-thienyl)biphenyl] can be doped with cations, their stability is poor, and their use as electrode materials has been limited.

Problems to be Solved by the Invention An object of the present invention is to obtain a novel organic semiconductor that is stable in the air, has a variety of color tones when developed, and can also be used as an electrode material.

Means for Solving the Problems As a result of extensive research in order to obtain such an organic semiconductor, the present inventors achieved the objective by introducing a naphthalene ring into the molecular chain of a thiophene polymer. They discovered scales, and based on this knowledge, they came up with the present invention. That is, the present invention relates to a polymer consisting of a repeating unit represented by the formula (in which the thienyl groups are present on the same benzene ring or on different benzene rings), and an organic polymer made by doping this polymer with an anion. It provides semiconductors.

The polymers of the present invention are novel compounds that have not yet been published in any literature, and have unique colors depending on their neutral state and oxidized state doped with anions, and are suitable for display materials. Although it is an electrical insulator in a neutral state, it exhibits semiconductor properties in an oxidized state.

Such anions include tetrafluoroborate ion, perchlorate ion, hexafluorophosphate ion,
Examples include hexafluoroarsenate ion, iodine ion, bromide ion, chloride ion, fluoride ion, sulfate ion, hydrogen sulfate ion, trifluoroacetate ion, p-toluenesulfonate ion, and the like. Furthermore, the polymer of the present invention can also be doped with cations, and in this case also exhibits a unique color. This means that it can be effectively used as a material, and the range of its use is expected to expand.

The thiophene polymer of the present invention can be produced, for example, by electropolymerizing a compound represented by the formula (in which the thienyl groups are present on the same benzene ring or on different benzene rings). The obtained polymer is doped with the anion of the supporting electrolyte used, but by reacting it with ammonia, the dopant is removed and a neutral polymer can be obtained.

The electropolymerization is advantageously carried out in a polar solvent and in an inert atmosphere. In this case, the polar solvent is acetonitrile,
Nitrobenzene, nitromethane, benzonitrile, propylene carbonate, tetrahydrofuran, methyl chloride, dimethyl sulfoxide, dimethylformamide, hexamethylphosphortriamide, 1-methyl-2-pyrrolidinone, dimethyl sulfate, diethyl sulfate, etc. are preferred, and inert Nitrogen, argon, etc. are used as the atmosphere. By performing the reaction under an inert atmosphere in this way, it is possible to prevent the reaction intermediate from combining with oxygen and producing by-products.

In addition to noble metals such as gold and platinum, glass electrodes in which indium oxide, stannic oxide, and the like are deposited on the glass surface are also used as electrode materials.

Supporting electrolytes include tetramethylammonium tetrafluoroborate, tetraethyl7monium tetrafluoroborate, and tetrafluoroborate.
Butylammonium, lithium tetrafluoroborate,
Tetramethylammonium perchlorate, tetraethylammonium perchlorate, tetra-n-butylammonium perchlorate, lithium perchlorate, tetramethylammonium hexafluorophosphate, tetra-hexafluorophosphate
n-butylammonium, hexafluorophosphate l.
Ruum, tetra-n-butylammonium hexafluoroarsenate, sodium hexafluoroarsenate, sulfuric acid, tetramethylammonium hydrogen sulfate, tetra-n-hydrogen sulfate
-butylammonium, sodium trifluoroacetate,
p-) TeI-ramethylammonium luenesulfonate,
Examples include tetra-n-butylammonium p-toluenesulfonate.

The compound (II) is synthesized, for example, by reacting 2-bromothiophene with magnesium metal to prepare a Grignard reagent, and adding the Grignard reagent to dibromnaphthalene for condensation.

ADVANTAGEOUS EFFECTS OF THE INVENTION The polymer of the present invention is obtained in an anion-doped state by electrolytic polymerization, and has the advantage that the polymerization and doping processes can be carried out substantially in one step.

The shape of the polymer is formed as a film on the electrode surface, and the thickness of the film can be adjusted by the amount of electricity passed through the electrolytic cell, making it possible to omit the molding process.

The dopant can be easily removed by reacting the anion-doped polymer obtained above with ammonia to neutralize the charge, resulting in a neutral polymer. Furthermore, when a negative potential is applied to the polymer formed on the electrode in the presence of a supporting electrolyte, negative ions are removed and then cations are doped. When a positive potential is applied to this, after the cations are removed, anions are doped again. Thus, the polymer of the present invention can be suitably used as an electrode material.

The polymer of the present invention exhibits different color tones in each of the doped state and the neutral state, and is suitable for use as a display material.
is possible.

In addition, the conductivity of the anion-doped polymer is 10-"
It shows a maximum of 1O-2S/cm from 37cm, is stable in the air, and can be applied to electromagnetic shielding materials, solar cells, etc.

The polymer (I) is insoluble in many solvents and has a degree of polymerization of 10-500.

The dedoped polymer in its neutral state is an insulator, but by adding electron acceptors such as bromine, iodine, sulfur trioxide, trifluoride, and pentafluoride antimony, it becomes a semiconductor again. It can also have the properties of

Example Next, the present invention will be explained in more detail with reference to Examples.

Reference example 1 2Of)+ with nitrogen introduction tube, stirrer, and condenser
In a nl three-neck flask, add 1.26 g of metallic magnesium (5
2 mmol), heated to 60°C, and flushed with nitrogen. After returning to room temperature, lithium aluminum hydroxide was dried with hydride and then distilled.
and 7.82 g (48 mmol) of 2-bromothiophene
When added, bubbles were generated and heat was generated. The resulting brown Grignard reagent is transferred to an addition funnel and used in the next reaction.

Separate nitrogen inlet tube, 200 with stirrer condenser
2,6-dipromnaphthalene 5 in m1 three-necked flask
．． 72 g (20 mmol), dichloro[1,3-bis(diphenylphosphino)propane]nickel (H)
22 mg (0.04 mmol) and 60 ml of the above-mentioned treatment of Tej. While flushing with nitrogen and stirring, the aforementioned Grignard reagent was gradually added. After the entire wall was added, the temperature was raised to 65°C and stirred for 4 hours.

50+nl of IN hydrochloric acid was added, and the resulting crystals were filtered and washed with water. After washing with 40 ml of saturated aqueous sodium bicarbonate solution, washing again with water and vacuum drying at 80°C for 1 hour, 2,6-di(2
-thienyl) naphthalene was obtained. Recrystallized from chloroform, yield 12.44 g (42%), melting point 258-25
9℃.

Elemental analysis value Calculated value (%) as Cl98I232 C73,94H4,14S 21.9
3 Actual measurement value (%) C73,72H3,95S 21.89
Reference Example 2 1,4-di(2-thienyl)naphthalene was obtained by carrying out the same operation as in Reference Example 1 except that 1,4-dibromonaphthalene was used instead of 2,6-dibromonaphthalene. Recrystallized from hexane.

Yield 0.77g (13%). Melting point 94.5-95.0
°C elemental analysis value Calculated value as Cl11H1252 (
%) C73,94H4,14S 21.93 Actual value (%) C73,39H4,06S 21.65 Example 1 One platinum plate (IX1=1cm2) was used for both negative and positive image electrodes.
2,6-di (2
-thienyl) naphthalene 88 mg (0.3 mmol)
, tetra-n-butylammonium tetrafluoroborate 494 mg (1.5 mmol), benzonitrile 3
11 ml was added and dissolved. After blowing argon for 15 minutes, electrolytic polymerization was performed for 15 seconds at a current density of 1 mA/cm 2 and a polymerization temperature of 25° C. to obtain a black-purple film doped with tetrafluoroborate ions on the anode.

Example 2 In Example 1, except that a glass electrode (IX2=2cm2) was used instead of the platinum plate as the anode and the polymerization time was 2 hours, tetrafluoroboric acid was deposited on the anode. An ion-doped black-purple film was obtained, the conductivity of which was 5.1XIO-2S/cm.

Next, this was immersed in 2 ml of ammonia water and washed with water and methanol to obtain 5.7 mg of a dark brown film from which the dopant had been removed. The infrared absorption spectrum of this polymer is shown in Figure (a). 79, which indicates the presence of a 2,5-disubstituted thiophene ring, as is clear from l.
A band of 0-795cr' was observed, indicating that the structure of the polymer was fully conjugated.

Example 3 A film on the platinum plate obtained in Example 1 was used as the working electrode, a platinum plate (IX1=1cm2) was used as the counter electrode, and silver tf! was used as the reference electrode. A cyclic portamogram was measured in an acetonitrile solution of 0.1 mol/I tetra-n-butylammonium tetrafluoroborate.

The peak potentials indicating doping and dedoping of tetrafluoroborate ions are +〇, 86V and +0.47V.
In addition, peak potentials of 2.40 V and -2.07 V indicating doping and dedoping of tetra-n-butylammonium ions were observed, respectively. This indicates that this heavy compound is capable of not only anion doping but also cation doping.

Further, the color of the polymer was yellow when the potential was around 0■, but it changed to gray-black by anion doping and to black by cation doping.

Example 4 In Example 2, 494 mg of tetrafluoropoate tetra-n-butylammonium (
By performing the same procedure, except using 512 mg (1.5 mmol) of tetra-n-butylammonium perchlorate instead of 1.5 mmol), a black film doped with perchlorate ions was formed on the anode. is obtained, and its conductivity is 4
．． It showed 4 X 10-'S/c+++.

Example 5 If the same operation as in Example 4 was performed except that nitrobenzene was used instead of benzonitrile as the solvent,
A black film doped with perchlorate ions on the anode is obtained, the conductivity of which is 2.0XIO-'S/cm.

Example 6 In Example 1, 1°4-
When the same procedure was performed except that 175 mg (0.6 mmol) of di(2-thienyl)naphthalene was used and the polymerization time was changed to 30 seconds, a green film doped with tetrafluoroborate ions was obtained on the anode. Ta.

Example 7 When the same operation as in Example 6 was performed except that a glass electrode (IX2 = 2 cm2) was used instead of the platinum plate as the anode and the polymerization time was changed to 2 hours, tetrafluoroborate ions were deposited on the anode. A black-edged film doped with was obtained, the conductivity of which was 2.5XI/3S/cm.

Next, this was immersed in 2 ml of ammonia water and washed with water and methanol to obtain 10.3 ug of a dark brown film from which the dopant had been removed. The infrared absorption spectrum of this polymer is shown in Figure (b). As is clear from this figure, 790
A band of -795c+n-' is observed, indicating that the structure of the polymer is fully conjugated.

Example 8 In Example 3, the same procedure was carried out, except that the film on the platinum plate obtained in Example 6 was used as the working electrode, and the cyclic portamogram was measured. Potentials indicating doping and dedoping of tetrafluoroborate ions were observed at +〇, 90V, and +0.57V, respectively, and potentials indicating doping and dedoping of tetra-n-butylammonium ions were observed at -2, 90V, and +0.57V, respectively. 02
V and -2.02V, respectively. Furthermore, the color of the polymer was yellow when the potential was around OV, but it changed to green due to anion doping and to grayish black due to cation doping.

[Brief explanation of the drawing]

The figure shows Example 2 [curve (a)] and Example 7 [curve 1)]
The infrared absorption spectrum of the dedoped polymer obtained in is shown.

Claims (1)

[Claims] 1. A polymer consisting of a repeating unit represented by the formula ▲ Numerical formula, chemical formula, table, etc. ▼ (The thienyl group in the formula exists on the same benzene ring or on different benzene rings) An organic semiconductor made by doping this polymer with anions. 2. Anions include tetrafluoroborate ion, perchlorate ion, hexafluorophosphate ion, hexafluoroarsenate ion, iodine ion, bromide ion, chloride ion, fluoride ion, sulfate ion, hydrogen sulfate ion, trifluoroacetate ion The organic semiconductor according to claim 1, which is p-toluenesulfonic acid ion. 3. Electrolytic polymerization of a naphthalene compound with two thiophene rings represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (The thienyl groups in the formula exist on the same or different benzene rings) A method for producing a polymer consisting of a repeating unit represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (The thienyl group in the formula has the same meaning as above).