Conductive polymer of poly(thio- or seleno-)phene type

Abstract

The present invention relates to a conductive polymer material of poly(thio- or seleno-)phene type containing at least two distinct species of counteranion, including a first species which is an anionic form of sulphuric acid, and a second species of counteranion selected from triflate, triflimidate, tosylate, mesylate, perchlorate and hexafluorophosphate. The invention also relates to a process for preparing such a material and the use thereof as conductive film. The invention also targets a substrate coated at least partly by a film of a material as defined above, a device comprising a material as defined above as conductive material, and also the use thereof in the organic electronics, organic thermoelectricity, organic photovoltaic and organic photodetector fields.

Claims

1. A conductive polymeric material including a poly(thio or seleno)phene type polymer comprising at least two distinct kinds of counteranions, including a first kind of counteranion which is an anionic form of sulfuric acid, and a second kind of counteranion selected from the group consisting of triflate and triflimidate.

2. The material as claimed in claim 1, comprising at least hydrogensulfate and triflate counteranions.

3. The material as claimed in claim 1, wherein the poly(thio or seleno)phene type polymer is a thiophene type polymer obtained by polymerizing at least one monomer selected from the group consisting of thiophene, 3-alkylthiophenes, 3,4-dialkylthiophenes, 3,4-cycloalkylthiophenes, 3,4-dialkoxythiophenes, and 3,4-alkylenedioxythiophenes, where the alkyl groups, if present, in the at least one monomer are: (i) identical or different, and (ii) represented by formula C.sub.nH.sub.2n+1 with n between 1 and 12.

4. The material as claimed in claim 1, wherein the poly(thio or seleno)phene type polymer is a thiophene type polymer obtained by polymerizing at least one monomer selected from the group consisting of thiophene, 3,4-ethylenedioxythiophene (EDOT), 3-hexylthiophene, and 3,4-propylenedioxythiophene (PRODOT).

5. The material as claimed in claim 1, wherein the poly(thio or seleno)phene type polymer is poly(3,4-ethylenedioxythiophene) (PEDOT).

6. The material as claimed in claim 1, wherein the poly(thio or seleno)phene type polymer is a selenophene type polymer obtained by polymerizing at least one monomer selected from the group consisting of selenophene, 3-alkylselenophenes, 3,4-dialkylselenophenes, 3,4-cycloalkylselenophenes, 3,4-dialkoxyselenophenes, and 3,4-alkylenedioxyselenophenes, where the alkyl groups, if present, in the at least one monomer are: (i) identical or different, and (ii) represented by formula C.sub.nH.sub.2n+1 with n between 1 and 12.

7. The material as claimed in claim 1, wherein the poly(thio or seleno)phene type polymer is a selenophene type polymer obtained by polymerizing at least one monomer selected from the group consisting of selenophene, 3,4-ethylenedioxyselenophene (EDOS), 3-hexylselenophene, and 3,4-propylenedioxyselenophene (PRODOS).

8. The material as claimed in claim 1, having a conductivity at least equal to 1000 S/cm, measured by the 4-point method, using a Loresta EP MCP-T360 conductivity meter.

9. A process for increasing the conductivity of a polymeric material including a poly(thio or seleno)phene type polymer comprising at least one first kind of counteranion which is an anionic form of sulfuric acid, and a second kind of counteranion chosen from triflate and triflimidate, wherein the polymeric material is provided in the form of a film on a surface of a solid substrate, the process comprising contacting said film with an aqueous solution of a sulfur-comprising acid under conditions favorable to the immobilization of an anionic form of said acid within the polymeric material.

10. A method for obtaining a conductive film, comprising coating a substrate with the material as claimed in claim 1.

11. A substrate coated at least in part with a film including the material as claimed in claim 1.

12. The substrate as claimed in claim 11, wherein the substrate is made of at least one material selected from the group consisting of glass, silicon, woven material, organic material, and polymeric material.

13. A device comprising, as conductor material, the material as claimed in claim 1.

14. The material as claimed in claim 1, having a conductivity varying from approximately 1500 S/cm to approximately 2500 S/cm, measured by the 4-point method, using a Loresta EP MCP-T360 conductivity meter.

Description

EXAMPLES

Example 1: Synthesis of PEDOT with Different Acid Treatments

(1) 2 ml of a 20% by weight solution of polyethylene glycol-polypropylene glycol-polyethylene glycol (PEG-PPG-PEG) (Mn=5800 g.Math.mol.sup.1) in ethanol are prepared with stirring in an ultrasonic bath for 4 hours.

(2) 240 mg of Fe(OTf).sub.3 are added to the solution with stirring.

(3) The solution is left stirring for an additional 30 minutes.

(4) The solution is subsequently cooled to 5 C. and 20 l of EDOT are added.

(5) The solution is immediately placed in an ultrasonic bath at 5 C. for 1 minute.

(6) The solution is spin coated onto a sheet of Corning Eagle XG glass (1010 cm) and then annealed for 10 minutes on a heating plate at 70 C. in the open air.

(7) The glass sheet is cut into 2.51.25 cm pieces and the conductivity of the films obtained is measured at 1200 S/cm (+/20 S/cm) by 4-point measurement for a mean thickness of 70 nm (+/5 nm).

(8) These films are dipped in an acid bath at pH=1 for one hour and then dried on a heating plate at 160 C. for 30 minutes.

(9) The conductivity of the films is measured by the Van der Pauw (4 point) method and compared with the value before acid treatment.

(10) The values are collated in the table below.

(11) TABLE-US-00001 Conductivity Conductivity after Sample (S/cm) Acid treatment treatment (S/cm) 1 1207 CF.sub.3SO.sub.3H (pH = 1) 1376 2 1192 HCl (pH = 1) 341 3 1230 HNO.sub.3 (pH = 1) 671 4 1215 CH.sub.3SO.sub.3H (pH = 1) 1690 for 1 h 5 1220 H.sub.2SO.sub.4 (pH = 1) 2541 for 1 h

(12) It is noticed that samples 1, 4 and 5, which have been subjected to a treatment with a sulfur-comprising or sulfonic acid, exhibit very high conductivities after treatment, in contrast to samples 2 and 3, which were treated with HCl or HNO.sub.3.

Example 2: Synthesis of Highly Conductive PEDOT:HSO4

(13) 2 ml of a 20% by weight solution of PEG-PPG-PEG (Mn=5800 g.Math.mol.sup.1) in ethanol are prepared with stirring in an ultrasonic bath for 4 hours.

(14) 240 mg of Fe(OTf).sub.3 are added to the solution with stirring.

(15) The solution is left stirring for an additional 30 minutes.

(16) The solution is subsequently cooled to 5 C. and 20 l of EDOT are added.

(17) The solution is immediately placed in an ultrasonic bath at 5 C. for 1 minute.

(18) The solution is spin coated onto a sheet of Corning Eagle XG glass (1010 cm) and then annealed for 10 minutes on a heating plate at 70 C. in the open air.

(19) The glass sheet is cut into 2.51.25 cm pieces and the conductivity of the films obtained is measured at 1200 S/cm (+/20 S/cm) by 4-point measurement for a mean thickness of 70 nm (+/5 nm).

(20) These films are dipped in a bath of sulfuric acid at pH=1 for a predetermined period of time (1 min, 10 min, 30 min, 1 h, 2 h, 5 h or 24 h) and then dried on a heating plate at 160 C. for 30 minutes.

(21) The conductivity of the films is measured by the Van der Pauw (4 point) method and compared with the value before acid treatment.

(22) The values are collated in the table below.

(23) TABLE-US-00002 Conductivity Conductivity after Sample (S/cm) Acid treatment treatment (S/cm) 6 1262 H.sub.2SO.sub.4 (pH = 1) 1450 for 1 min 7 1189 H.sub.2SO.sub.4 (pH = 1) 1806 for 10 min 8 1189 H.sub.2SO.sub.4 (pH = 1) 2502 for 30 min 9 1301 H.sub.2SO.sub.4 (pH = 1) 2480 for 1 h 10 1338 H.sub.2SO.sub.4 (pH = 1) 2512 for 2 h 11 1186 H.sub.2SO.sub.4 (pH = 1) 2521 for 24 h

(24) All of the samples treated with H.sub.2SO.sub.4 have very high conductivities after treatment. The conductivities after acid treatment are all the higher when the treatment time is greater than 30 minutes.

Example 3: Synthesis of Highly Conductive PEDOT:HSO4

(25) 2 ml of a 20% by weight solution of PEG-PPG-PEG (Mn=5800 g.Math.mol.sup.1) in ethanol are prepared with stirring in an ultrasonic bath for 4 hours.

(26) 240 mg of Fe(OTf).sub.3 are added to the solution with stirring.

(27) The solution is left stirring for an additional 30 minutes.

(28) The solution is subsequently cooled to 5 C. and 20 l of EDOT are added.

(29) The solution is immediately placed in an ultrasonic bath at 5 C. for 1 minute.

(30) The solution is spin coated onto a sheet of Corning Eagle XG glass (1010 cm) and then annealed for 10 minutes on a heating plate at 70 C. in the open air.

(31) The glass sheet is cut into 2.51.25 cm pieces and the conductivity of the films obtained is measured at 1200 S/cm (+/20 S/cm) by 4-point measurement for a mean thickness of 70 nm (+/5 nm).

(32) These films are dipped in a bath of sulfuric acid at pH=1 for 30 minutes and then dried on a heating plate at different temperatures (140 C., 160 C. or 180 C.) for 30 minutes.

(33) The conductivity of the films is measured by the Van der Pauw (4 point) method and compared with the value before acid treatment.

(34) The values are collated in the table below.

(35) TABLE-US-00003 Conductivity Conductivity after Sample (S/cm) Acid treatment treatment (S/cm) 12 1238 H.sub.2SO.sub.4 (pH = 1) at 1920 140 C. 13 1276 H.sub.2SO.sub.4 (pH = 1) at 2520 160 C. 14 1286 H.sub.2SO.sub.4 (pH = 1) at 1723 180 C. 15 1238 H.sub.2SO.sub.4 (pH = 1) at 1453 200 C.

(36) All of the samples treated with H.sub.2SO.sub.4 have very high conductivities after treatment. The conductivities after acid treatment are all the higher when the treatment temperature is 160 C.

Example 4: Synthesis of Highly Conductive PRODOT:HSO4

(37) 2 ml of a 20% by weight solution of PEG-PPG-PEG (Mn=5800 g.Math.mol.sup.1) in ethanol are prepared with stirring in an ultrasonic bath for 4 hours.

(38) 240 mg of Fe(OTf).sub.3 are added to the solution with stirring.

(39) The solution is left stirring for an additional 30 minutes.

(40) The solution is subsequently cooled to 5 C. and 25 l of 3,4-propylenedioxythiophene (PRODOT) are added.

(41) The solution is immediately placed in an ultrasonic bath at 5 C. for 1 minute.

(42) The solution is spin coated onto a sheet of Corning Eagle XG glass (2.52.5 cm) and then annealed for 10 minutes on a heating plate at 70 C. in the open air.

(43) The film is dipped in a bath of sulfuric acid at pH=1 for 30 minutes and then dried on a heating plate at 160 C. for 30 minutes.

(44) The conductivity of the film, measured by the Van der Pauw (4 point) method, is 1500 S.Math.cm.sup.1 and its thickness is 70 nm (+/5 nm).

Example 5: Synthesis of Highly Conductive PEDOS:HSO4

(45) 2 ml of a 20% by weight solution of PEG-PPG-PEG (Mn=5800 g.Math.mol.sup.1) in ethanol are prepared with stirring in an ultrasonic bath for 4 hours.

(46) 240 mg of Fe(OTf).sub.3 are added to the solution with stirring.

(47) The solution is left stirring for an additional 30 minutes.

(48) The solution is subsequently cooled to 5 C. and 25 l of 3,4-ethylenedioxyselenophene (EDOS) are added.

(49) The solution is immediately placed in an ultrasonic bath at 5 C. for 1 minute.

(50) The solution is spin coated onto a sheet of Corning Eagle XG glass (2.52.5 cm) and then annealed for 10 minutes on a heating plate at 70 C. in the open air.

(51) The film is dipped in a bath of sulfuric acid at pH=1 for 30 minutes and then dried on a heating plate at 160 C. for 30 minutes.

(52) The conductivity of the film, measured by the Van der Pauw (4 point) method, is 1650 S.Math.cm.sup.1 and its thickness is 70 nm (+/5 nm).

Example 6: Synthesis of Highly Conductive PEDOT:HSO4 from PEDOT:OTs

(53) 2 ml of a 20% by weight solution of PEG-PPG-PEG (Mn=5800 g.Math.mol.sup.1) in ethanol are prepared with stirring in an ultrasonic bath for 4 hours.

(54) 240 mg of Fe(OTf).sub.3 are added to the solution with stirring.

(55) The solution is left stirring for an additional 30 minutes.

(56) The solution is subsequently cooled to 5 C. and 20 l of 3,4-ethylenedioxythiophene (EDOT) are added.

(57) The solution is immediately placed in an ultrasonic bath at 5 C. for 1 minute.

(58) The solution is spin coated onto a sheet of Corning Eagle XG glass (2.52.5 cm) and then annealed for 10 minutes on a heating plate at 70 C. in the open air.

(59) The film is dipped in a bath of sulfuric acid at pH=1 for 30 minutes and then dried on a heating plate at 160 C. for 30 minutes.

(60) The conductivity of the film, measured by the Van der Pauw (4 point) method, is 1750 S.Math.cm.sup.1 and its thickness is 70 nm (+/5 nm).