JPS5846268B2 - organic polymer semiconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an organic polymer semiconductor based on a novel linear polyJ (2,5-thennylene) polymer having 2,5-thhenylene groups as repeating units.

Conventional materials for organic polymer semiconductors include polyacetylene,
Poly(paraphenylene), poly(phenylene sulfide), etc. are known.

However, these polymers are susceptible to the action of oxygen, and therefore organic semiconductors made by adding electron acceptors to these polymers are susceptible to oxygen in the air, and extremely toxic substances such as ASF are susceptible to the action of oxygen. Many of them exhibit electrical conductivity only by adding an electron acceptor, and therefore have drawbacks such as a lack of safety for the human body.

An object of the present invention is to obtain an excellent organic polymer semiconductor that does not have such drawbacks.

The present invention has a 2,5-thennylene group represented by the following formula as a repeating unit, is regularly bonded at the 2 and 5 positions, and has an average degree of polymerization of 14
The present invention provides an organic polymer semiconductor characterized by adding a linear po-1,1 (2,5-thhenylene) polymer Jc electron acceptor having a molecular weight of 1 to 30.

Conventionally, several examples of linear polythenylene polymers having a thiophene ring or skeleton structure are known as shown in the following formula: However, in all of these polymers, a thiophene ring is incorporated into the polymer skeleton structure. The bonding mode when polymerizing is not constant, and the average degree of polymerization n
is a polymer with a small value of 7 or less, and poly-1.1 (2,5-thennylene) regularly bonded at the 2 and 5 positions.
No polymer has ever been obtained.

☆ ☆ On the other hand, the linear poly(5-thennylene) polymer used in the present invention (hereinafter referred to as linear poly(5-thennylene)) has a resonance structure represented by the following formula: with an average degree of polymerization of 14 to 30
It has a different structure and a higher average degree of polymerization than conventional polythenylene polymers.

Such a polymer has the above-mentioned resonance structure and is colored in a deep color because it has a pi-electron conjugated system along the main chain J.

Further, as the degree of polymerization increases, the pi-electron conjugated system is expanded, and as a result, the position of the thickest absorption in the visible absorption spectrum moves toward the longer wavelength side as the degree of polymerization increases.

As a result, polymers with an average degree of polymerization of about 14 are colored brown, and polymers with an average degree of polymerization of about 20 or more are colored black or reddish-black.

In addition, linear poly(2,5-chenylene) used in the present invention
Because the polymer has the above pi-electron conjugated system, it has a high affinity for inorganic electron acceptors such as iodine, sulfur dioxide, and sulfuric acid, and organic electron acceptors such as tetracyanoquinodimethane and tetracyanoethylene. strongly adsorbs electron acceptors.

In general, in order for a polymer to exhibit high affinity for the above-mentioned electron acceptors, it is essential that a sufficiently expanded pi-electron system exists in the polymer molecule.
In the linear polythenylene polymer, it is necessary that the thiophene rings are bonded regularly at the 2 and 5 positions and that the average degree of polymerization thereof is greater than a certain level.

Furthermore, since the adduct consisting of a polymer and an electron acceptor has semiconductor properties, that is, the property that carriers can easily move in the polymer, it is
The average degree of polymerization of the polymer is required to be greater than a certain level.

The linear poIJ (2,5-chenylene) polymer used in the present invention, which is regularly bonded at the 2 and 5 positions and has an average degree of polymerization of 14 or more, satisfies these requirements.

The polymer used in the present invention can be molded by various molding methods for thermoplastic resins such as compression molding, and the molded product has excellent mechanical strength and excellent heat resistance with high thermal stability. If the resin is inert to oxygen in the air and no electron acceptor is added, it is an electrical insulator, and as mentioned above, it is an ordinary non-toxic material. Since it is converted into an organic semiconductor by adding an electron acceptor, it is extremely excellent as a semiconductor material.

The polymer used in the present invention is produced by using a nickel compound as a catalyst in a non-reactive solvent in substantially the absence of water.
It is produced by reacting 2,5-dihalogenated thiophene with magnesium.

This reaction has the following reaction formula: (X in the formula represents a halogen atom).

In such a polymerization reaction by dehalogenation using magnesium, it is necessary to use a nickel compound as a catalyst.

Although the polymerization reaction proceeds to some extent even when no catalyst is used, the reaction rate is extremely slow and the yield of polymer is almost zero even after heating for several days.

The catalyst may be added after the reaction of the 2,5-dihalogenated thiophene and magnesium, or at the beginning of the reaction.

As the nickel compound of the catalyst, NiC, /S2゜Ni
Nickel halides such as Br2, and dichloro(2,2'bipidine)nickel N1C12 (bpy
), dichlorobis(triphenylphosphine)nickel Ni Br 2 (pph3)l! , 1,5-cyclooctadienebis(triphenylphosphine)nickel N
Preference is given to using nickel complexes such as i (cod) (pphs) 2.

The amount of catalyst used is 0.01 of 2,5 dihalogenated thiophene.
It is appropriate that the weight is 0.5 to 0.5 da.

Non-reactive solvents include 2,5 ether solvents, etc.
- Using a solvent that dissolves the dihalogenated thiophene.

Examples of ether solvents include tetrahydrofuran, diethyl ether, dibutyl ether, and the like.

Furthermore, the reaction is carried out under conditions that minimize the presence of water in the reaction mixture.

The reason for this is that the organomagnesium compound produced as a polymerization reaction active species by the reaction between 2,5-dihalogenated thiophene and magnesium is unstable in water and decomposes, which hinders the progress of the polymerization reaction. This is because it will be done.

Furthermore, the reaction is preferably carried out in an inert atmosphere.

The reason for this is that the organomagnesium compound reacts with moisture, carbon dioxide, and oxygen in the air, and the progress of the polymerization reaction is hindered.

The reaction is usually carried out at room temperature to solvent reflux temperature, although a wide range of temperatures can be used.

The reaction proceeds even at 0°C, but in this case some induction period is required.

The amount of magnesium added is suitably 0.98 to 1.10 gram atoms per mole of 2,5-dino)rodanated thiophene.

Next, the present invention will be explained with reference to examples.

Experimental example 1 2.5-dibromothiophene5. (LP (21 mmol) was placed in a 200 ml four-Low flask, and dried tetrahydrofuran 157,711 and metallic magnesium 0
．． 51? (21 milligram atoms) was added and allowed to react with stirring at room temperature under a dry nitrogen atmosphere.

After about an hour, it was confirmed that the metallic magnesium was almost completely consumed.

Next, when dichlorobis(2,2'-bipyridine)nickel Ni C1,z(bpy)201n9 (0.07 mmol) was added and heated, the polymerization reaction started smoothly at room temperature, and a dark brown polymer began to precipitate. Ta.

The polymerization reaction was completed in about 1 hour, but was further heated under refluxing tetrahydrofuran for 2 hours to complete the polymerization reaction.

The formed precipitate was taken up in hydrochloric acid acidic methyl alcohol,
After stirring for 1 hour, the mixture was collected on a glass filter and thoroughly washed with methyl alcohol and water.

Next, this precipitate was extracted with hot methyl alcohol using a Soxhlet extractor for 1 hour to extract and remove low molecular compounds.
By drying, a powdery blackish brown polymer 1.22 was obtained.

This polymer had an average degree of polymerization of about 27.5, as calculated from the average degree of polymerization and weight ratio of the two components separated by hot chloroform extraction as described below.

This polymer showed extremely high thermal stability without melting at 200°C.

The results of thermogravimetric analysis of this polymer conducted under a nitrogen atmosphere are shown in FIG.

From Figure 1, the thermal decomposition of this polymer takes place at 230°C under nitrogen atmosphere.
℃, but it can be seen that even at a high temperature of 900 degrees Celsius, the maximum remaining weight is about 35 times.

As shown in Figure 2, the infrared absorption spectrum of this polymer is based on the 2,5-thennylene group in the polymer main chain.
It shows one sharp absorption in the Korean region, but no other absorption in the out-of-plane bending vibration region.

Furthermore, the C-Br stretching vibration appearing around 960c1rt' was also small.

This indicates that the produced polymer has a sufficiently large degree of polymerization and is composed of regular repeating units, supporting the structure shown in formula (1).

This dark brown polymer was further extracted with hot chloroform for 50 hours using a Soxhlet extractor.

As a result, 0.26 P (approximately 22 times maximum) of a powdery brown polymer extracted with hot chloroform and 0.94 P (approximately 78 weight φ) of a powdery black polymer that was not extracted with hot chloroform were obtained.

Elemental analysis of the brown hot chloroform soluble polymer was 53.1% carbon and 2.8% hydrogen.

Considering that this polymer has a structure in which Br atoms are bonded to both ends of the polymer as represented by the following formula, the average degree of polymerization n calculated from the carbon analysis value is approximately 19, which indicates that the polymerization The average molecular weight of the combined product was approximately 1,720.

Approximately half of this hot chloroform-soluble polymer is chloroform-soluble even at room temperature, and this portion
The number average molecular weight was measured by vapor pressure permeation method using a 17 molecular weight measuring device (manufactured by Haake, West Germany) and chloroform, and found to be about 1,370.

Considering the structure of formula (3), this molecular weight is determined by the average degree of polymerization n
This corresponds to a case where the value of is approximately 14.8.

The average degree of polymerization and weight ratio of the hot chloroform soluble polymer and room temperature chloroform soluble polymer described above (approximately 1:1
), the average degree of polymerization n of the polymer soluble in hot chloroform and insoluble in room temperature chloroform was about 23, and the average molecular weight was about 2,050.

Elemental analysis of the black thermally chloroform-insoluble polymer was 53.7% carbon and 2.6% hydrogen, but 2.1% ash was present (this ash was composed of magnesium produced during the polymerization reaction). The compound is a linear poIJ (2,5-
It is thought that the coordination of sulfur in the polymer (chenylene) is incorporated into the polymer.

Therefore, when this ash content is excluded, the elemental analysis value of this polymer is 54.9% carbon and 2.7% hydrogen, and the average degree of polymerization n of this polymer calculated from the carbon analysis value is (3).
Considering the structure of the formula, it is about 30, and the average molecular weight is about 26.
It was 20.

The thermally chloroform-insoluble polymer did not melt at 360°C and exhibited extremely high thermal stability.

The results of thermogravimetric analysis of this polymer conducted under a nitrogen atmosphere are shown in FIG.

From Figure 3, it can be seen that the thermal decomposition of this polymer is 250% under nitrogen atmosphere.
Although it starts at around 90°C, it can be seen that even at a high temperature of 900°C, the residual weight of the rice cake is about 50 weight.

As shown in Figure 4, the infrared absorption spectrum of this thermally chloroform-insoluble polymer shows one sharp absorption at 788CTL' (based on the 2,5-thennylene group in the main chain of the polymer); It showed no absorption in the out-of-plane bending vibration region.

Furthermore, the C-Br stretching vibration appearing around 960 cm was even smaller than that of the polymer before hot chloroform extraction.

This indicates that the thermally chloroform-insoluble polymer has a sufficiently large average degree of polymerization and is preempted from regular repeating units, supporting the structure shown in formula (1).

The lower relative proportion of C-Br bonds than in the polymer before hot chloroform extraction indicates that the average degree of polymerization of the hot chloroform-insoluble polymer is greater than that of the polymer before hot chloroform extraction.

Both thermal chloroform-soluble polymers and thermal chloroform-insoluble polymers showed no change in appearance or infrared absorption spectra when left in air at room temperature for one year. It was stable against

Experimental Example 2 2.5-dibromothiophene 4.9S' (20 mmol), 20 ml of dry tetrahydrofuran, 0.495' (20 milligram atoms) of metallic magnesium and 2
0rn9 Ni Ct2 (bpy) 200m#)
The mixture was placed in a four-day flask and stirred at room temperature under a dry nitrogen atmosphere for 10 hours.

The generated precipitate was collected and washed in the same manner as in Example 1,
Furthermore, by removing the hot methyl alcohol soluble content using a Soxhlet extractor, a powdery black-brown poly(2
, 5-chenylene) polymer 0.90P was obtained.

This polymer has almost the same stability against oxygen σ in the air as the hot methyl alcohol-insoluble dark brown polymer obtained in Experimental Example 1, and also exhibits almost the same thermal stability and infrared absorption spectrum. It is believed that it has approximately the same average degree of polymerization as the hot methyl alcohol-insoluble polymer obtained in Example 1.

Experimental example 3 2.5-dibromothiophene4. ．． 4P (18 mmol) was placed in a 200 Tll four-day flask, and 20 ml of dry tetrahydrofuran and 0.0 mmol of metallic magnesium were added thereto.
44P (18: IJ gram atom) was added and reacted for 1 hour with stirring at room temperature under a dry nitrogen atmosphere.

Next, when N1Ct214rn9 is added and stirred,
The polymerization reaction started smoothly at room temperature, and a dark brown polymer began to precipitate.

The precipitate formed after reacting for 5 hours at room temperature was
By collecting and washing in the same manner as in Experimental Example 1 and further removing the soluble content in hot methyl alcohol using a Soxhlet extractor, a powdery black-brown poly(2°5-chenylene) polymer 0.9Or was obtained. Obtained.

The elemental analysis of this polymer was 53.2% carbon and 2% hydrogen.
．． Although it was ranked 5th grade, it had the highest ash content of 1.6 layers.

Therefore, if this ash content is excluded, the elemental analysis value of this polymer is 54.1% carbon and 2.5% hydrogen, and the average degree of polymerization n of this polymer calculated from the elemental analysis value of carbon.
was about 24 considering the structure of formula (3), and the average molecular weight was about 2130.

When this polymer is left in air at room temperature for one year,
No change was observed in the appearance or infrared absorption spectrum, and it was stable against oxygen in the air.

Experimental Example 4 A reaction was carried out in the same manner as in Experimental Example 1 without using a catalyst.

However, the polymerization reaction was carried out at room temperature for 1 hour and then further carried out for 4 hours under refluxing of tetrahydrofuran.

The yield of polymer was zero. Experimental Example 5 The reaction was carried out in the same manner as in Experimental Example 4, except that 2.5-dibromothiophene 6.42P (26 mmol), metallic magnesium 6.55P (26 mmol), and PaC12 (bpy) 23■ were used as the catalyst. I did this.

The yield of polymer was zero. Experimental Example 6 Experimental Example 1 The powder of the dark brown polymer (average degree of polymerization of about 27.5) obtained after extraction with hot methyl alcohol in Experimental Example 1 was heated to 500 kg/c using an infrared molder (manufactured by Shimadzu Corporation).
It was solidified under a pressure of yyf, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 7.3 x 10 Ω at 18°C.
It was a rose.

This polymer powder was exposed to iodine vapor in a glass container at room temperature to absorb iodine for io hours to obtain a powder containing 57 iodine by weight per polymer used.

The iodine content was determined from the weight increase upon absorption of iodine.

This powder was solidified in the same manner as described above, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is s at 18℃, 5xio Ωα, 80℃
The result was 4.6×10 Ω・snoring.

When this semiconductor was left in air at room temperature for one year, no change was observed in its appearance or infrared absorption spectrum, and it was stable against oxygen in the air, and its electrical conductivity was also low. virtually unchanged.

Experimental Example 7 In fact, a powder of the same dark brown polymer (average degree of polymerization of about 27.5) as used in Experimental Example 6 was added to concentrated sulfuric acid at room temperature.
After absorbing sulfuric acid for 30 minutes, it was thoroughly washed with methyl alcohol to remove the sulfuric acid adhering to the surface to obtain a powder containing H280, 35% by weight per polymer used.

The sulfuric acid content was determined from the weight increase upon absorption of sulfuric acid.

This powder was solidified in the same manner as in Experimental Example 6, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 8.6×10 Ω at 28℃, 8
It was 1.8×10 Ω at 0°C.

When this semiconductor was left in dry air at room temperature for one year, no change was observed in its appearance or infrared absorption spectrum, and it was stable against oxygen in the air, and its electrical conductivity was also low. virtually unchanged.

Experimental Example 8 The black thermally chloroform-insoluble polymer (average degree of polymerization of about 30) obtained in Experimental Example 1 was solidified in the same manner as in Experimental Example 6,
The electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 5.3×10”Ω・α at 18℃
Met.

This polymer powder was exposed to iodine vapor in the same manner as in Experimental Example 6, and iodine was absorbed for 10 hours to obtain a powder containing a maximum of 49 iodine molecules per polymer used.

The iodine content was determined from the weight increase upon absorption of iodine.

This powder was solidified in the same manner as described above, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 3.4 x 10 Ω at 18℃ ・At 81℃
The resistance was 1.3×10 Ω.

When this semiconductor is left in air at room temperature for one year,
No change was observed in the appearance or infrared absorption spectrum, and it was stable against oxygen in the air, and the electrical conductivity did not change substantially.

Experimental Example 9 A hot methyl alcohol-insoluble black polymer (average degree of polymerization of about 27 , 5) was solidified in the same manner as in Experimental Example 6, and the electrical conductivity of the obtained plate-like material was measured.

The electrical conductivity was 7.3×10 Ω·m at 18°C.

This polymer powder was exposed to iodine vapor in a glass container at room temperature to absorb iodine for 10 hours to obtain a powder containing 57 weight φ of iodine per polymer used.

The iodine content was determined from the weight increase upon absorption of iodine.

This powder was solidified in the same manner as described above, and the electrical conductivity of the obtained plate-like material was measured.

The electrical conductivity was 1×10 Ω crrL at 18°C and 5×10 Ω −m at 80°C.

This semiconductor showed no change in appearance or infrared absorption spectrum when left in air at room temperature for one year, was stable against oxygen in the air, and had virtually no electrical conductivity. There was no significant change.

Experimental Example 10 Powder of the same dark brown polymer (average degree of polymerization of about 27.5) as used in Experimental Example 9 was added to concentrated sulfuric acid at room temperature, and after absorbing the sulfuric acid for 30 minutes, it was thoroughly washed with methyl alcohol. The sulfuric acid adhering to the surface was removed to obtain a powder containing 35% by weight of H2So per polymer used.

The sulfuric acid content was determined from the weight increase upon absorption of sulfuric acid.

This powder was solidified in the same manner as in Experimental Example 9, and the electrical conductivity of the obtained plate-like material was measured.

Electrical conductivity is 8X10-3Ω-1cm at 28℃ 8
It was 2×10 Ω −m at 0°C.

This semiconductor showed no change in appearance or infrared absorption spectrum when left in dry air at room temperature for one year, was stable against oxygen in dry air, and was electrically conductive. The rate also remained virtually unchanged.

Experimental Example 11 A black thermally chloroform-insoluble polymer (average polymerization 30) was solidified in the same manner as in Experimental Example 9, and the electrical conductivity of the obtained plate-like material was measured.

The electrical conductivity was 5.3×10 Ω·bi at 18°C.

This polymer powder was exposed to iodine vapor in the same manner as in Experimental Example 9 to absorb iodine for 10 hours to obtain a powder containing over 49% by weight of iodine per polymer used.

The iodine content was determined from the weight increase upon absorption of iodine.

This powder was solidified in the same manner as described above, and the electrical conductivity of the obtained plate-like material was measured.

The electrical conductivity is 8 x 10 Ω at 18°C and 6 at 81°C.
X10-2Ω-1CIIL' Tea Tsuta.

[Brief explanation of drawings]

Figure 1 is a graph showing the results of thermogravimetric analysis of one example of the linear poIJ (2,5-thennylene) polymer used in the present invention, Figure 2 is its infrared absorption spectrum, and Figure 3 is FIG. 4 is a graph showing the results of thermogravimetric analysis of another example of the linear poly(2,5-thennylene) polymer used, and FIG. 4 is its infrared absorption spectrum.

Claims (1)

[Claims] Primary formula: A 2,5-thennylene group represented by the following is used as a repeating unit,
Regularly bonded at the 2 and 5 positions, with an average degree of polymerization of 14 to 30
An organic polymer semiconductor characterized by being formed by adding an electron acceptor to a linear poly(2,5-chenylene) polymer.