阅读说明：本技术 Pedot:pss空穴传输材料的掺杂改性方法 (Doping modification method of PEDOT (PEDOT-PSS) hole transport material ) 是由 李昱达 汪锋 于 2021-07-21 设计创作，主要内容包括：本发明公开了一种PEDOT:PSS空穴传输材料的掺杂改性方法,包括如下步骤：向PEDOT:PSS溶液中加入小分子掺杂剂,室温搅拌得到均质体系；采用透析处理移除体系中的小分子掺杂剂,得到改性PEDOT:PSS产品。本发明采用二次掺杂剂添加改性与透析技术相结合的方式,有效解决了传统单一后处理模式中成膜性与导电性此消彼长的问题,实现导电性与成膜性同步提升,大幅提高有机光电器件性能。(The invention discloses a doping modification method of a PEDOT/PSS hole transport material, which comprises the following steps: adding a small molecular dopant into a PEDOT (PSS) solution, and stirring at room temperature to obtain a homogeneous system; and removing the small molecular dopant in the system by dialysis treatment to obtain a modified PEDOT/PSS product. The invention adopts a mode of combining secondary dopant addition modification and dialysis technology, effectively solves the problem of film forming property and conductivity trade off in the traditional single post-treatment mode, realizes the synchronous promotion of conductivity and film forming property, and greatly improves the performance of the organic photoelectric device.)

The doping modification method of the PEDOT/PSS hole transport material is characterized by comprising the following steps:

(1) adding a small molecular dopant into a PEDOT (PSS) solution, and stirring at room temperature to obtain a homogeneous system;

(2) and removing the small molecular dopant in the system by dialysis treatment to obtain a modified PEDOT/PSS product.

2. The doping modification method of PEDOT PSS hole transport material according to claim 1, characterized in that the small molecule dopant is one or mixture of small molecule alcohol, small molecule acid, small molecule salt and small molecule surfactant.

3. The method for doping and modifying the PEDOT PSS hole transport material according to claim 1, wherein the small molecular alcohol is methanol, ethanol, propanol, ethylene glycol, isopropanol, glycerol or sorbitol.

4. The method for doping and modifying the PEDOT PSS hole transport material according to claim 1, wherein the small molecular acid is sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid or p-toluenesulfonic acid.

5. The method for doping and modifying the PEDOT PSS hole transport material according to claim 1, wherein the small molecule salt is sodium chloride, potassium chloride, lithium chloride or lithium bis (trifluoromethanesulfonimide).

6. The doping modification method of PEDOT PSS hole transport material according to claim 1, characterized in that the small molecule surfactant is sodium dodecyl benzene sulfonate, alkyl polyoxyethylene ether, perfluoro caprylic acid; small molecule sulfones and sulfoxides, N-dimethylformamide, dimethyl sulfoxide (DMSO) or N-methylacetamide.

7. The doping modification method of the PEDOT/PSS hole transport material according to claim 1, wherein the mass ratio of the small molecular dopant in the step (1) to the PEDOT/PSS solution is 1 (2-50).

8. The doping modification method of the PEDOT/PSS hole transport material according to claim 1, wherein the stirring condition at room temperature in the step (1) is 200-800 rpm for 1-24 h.

9. The method for doping and modifying the PEDOT PSS hole transport material according to claim 1, wherein the dialysis treatment in the step (2) is dialysis for 10-240 min by using a dialysis bag with a molecular weight cut-off of 500-10000 Da.

Technical Field

The invention belongs to the technical field of organic semiconductor materials, and particularly relates to a doping modification method of a PEDOT/PSS hole transport material.

Background

In 1989, the German Bayer company invented PEDOT, which has excellent conductivity and environmental stability, and has the characteristics of high visible light transmittance, adjustable photoelectromagnetism and the like, is concerned, rapidly becomes a star molecule in the field of conductive polymers, but the characteristics of insolubility and insolubility limit the processing and application of PEDOT. Subsequently, the German Bayer company invents that PSS is dispersed and doped to prepare PEDOT-PSS conductive polymer dispersion liquid, effectively solves the problem of difficult processing, and is widely applied to the fields of antistatic coatings, optoelectronic devices and the like due to excellent solution processability and film forming property, thereby dominating the conductive polymer market for nearly 30 years.

With the development of the field of optoelectronic devices, the current property parameters (conductivity, work function, surface free energy and the like) of the PEDOT/PSS conductive polymer film cannot meet the requirements of a new generation of photoelectric active main body materials, and the further increase of the performance of the optoelectronic devices is limited. The modification of post-treatment, i.e. adding secondary dopant to PEDOT: PSS dispersion or soaking PEDOT: PSS film with secondary dopant, can increase the PEDOT quinoid configuration content and the PEDOT continuous phase size, and simultaneously reduce the PSS insulation component content, and show great research value in the aspect of increasing the PEDOT: PSS conductivity (Advanced Materials 2016,28, 8625; Advanced Electronic Materials,2015,1, 1500017).

Kim et al added a secondary dopant, dimethyl sulfoxide, to a PEDOT: PSS dispersion for the first time, effectively increasing the film conductivity (Synthetic Metals 2002,126,311). The patent CN102482403A adopts a composite secondary doping agent of diglycolic anhydride and dimethyl sulfoxide to further improve the conductivity of the PEDOT-PSS film. Soaking PEDOT: PSS films in sulfuric acid by Lee et al resulted in a significant increase in film conductivity (Advanced Materials 2014,26, 2268).

However, conventional post-treatment modification processes increase the conductivity of PEDOT: PSS at the expense of film-forming properties (including uniformity and smoothness) (ACS Applied Materials & Interfaces,2015,7, 19764; Materials Chemistry Frontiers 2020,4, 3302; Science Advance 2017,3, e1602076), resulting in limited performance of organic optoelectronic devices assembled with it as a hole transport material.

Disclosure of Invention

The invention aims to provide a doping modification method of a PEDOT/PSS hole transport material, which can not only improve the conductivity, but also eliminate the influence of a modifier on the film forming property of the PEDOT/PSS hole transport material.

In order to achieve the purpose, the technical scheme is as follows:

the doping modification method of the PEDOT/PSS hole transport material comprises the following steps:

(1) adding a small molecular dopant into a PEDOT (PSS) solution, and stirring at room temperature to obtain a homogeneous system;

(2) and removing the small molecular dopant in the system by dialysis treatment to obtain a modified PEDOT/PSS product.

According to the scheme, the micromolecular dopant is one or a mixture of micromolecular alcohol, micromolecular acid, micromolecular salt and micromolecular surfactant.

According to the scheme, the small molecular alcohol is methanol, ethanol, propanol, ethylene glycol, isopropanol, glycerol or sorbitol.

According to the scheme, the small molecular acid is sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid or p-toluenesulfonic acid.

According to the scheme, the small molecular salt is sodium chloride, potassium chloride, lithium chloride or lithium bistrifluoromethanesulfonylimide.

According to the scheme, the small molecular surfactant is sodium dodecyl benzene sulfonate, alkyl polyoxyethylene ether and perfluorooctanoic acid; small molecule sulfones and sulfoxides, N-dimethylformamide, dimethyl sulfoxide (DMSO) or N-methylacetamide.

According to the scheme, the mass ratio of the small molecular dopant to the PEDOT/PSS solution in the step (1) is 1 (2-50).

According to the scheme, the room-temperature stirring condition in the step (1) is 200-800 rpm for 1-24 hours.

According to the scheme, the dialysis treatment in the step (2) is dialysis for 10-240 min by using a dialysis bag with the molecular weight cutoff of 500-10000 Da.

The invention has the beneficial effects that:

according to the invention, on the basis of a secondary doping method, a micromolecule dopant in a dialysis treatment removal system is introduced, so that the problem of the trade-off between film forming property and conductivity in the traditional single post-treatment mode is effectively solved, the conductivity and the film forming property are synchronously improved, and the performance of an organic photoelectric device is greatly improved.

The method has the advantages of simple and efficient operation, green and environment-friendly process and low cost. And the removed small molecular dopant can be collected again and recycled, so that the sustainable production of the modified PEDOT/PSS product is realized.

Drawings

FIG. 1: film microscope pictures of the modified PEDOT: PSS samples obtained in example 3, the traditional DMSO secondary doping PEDOT: PSS samples and the commercial PEDOT: PSS (4083) samples after spin coating;

FIG. 2: atomic Force Microscopy (AFM) of spin-coated samples of modified PEDOT: PSS, conventional DMSO double-doped PEDOT: PSS and commercial PEDOT: PSS (4083) obtained in example 3;

FIG. 3: example 3I-V curves of spin-coated samples of modified PEDOT: PSS, conventional DMSO double-doped PEDOT: PSS and commercial PEDOT: PSS (4083).

Detailed Description

The following examples further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.

Example 1

To 19g of PEDOT: PSS dispersion was added 1g of N, N-dimethylformamide and stirred at room temperature at 200rpm for 12 h. And then dialyzing for 30min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid.

Example 2

To 15g of PEDOT: PSS dispersion was added 5g of DMSO and stirred at room temperature at 200rpm for 12 h. And then dialyzing for 120min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid.

Example 3

To 19g of PEDOT: PSS dispersion was added 1g of DMSO and stirred at room temperature at 200rpm for 12 h. And then dialyzing for 30min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid.

Description of the effects of the examples:

FIG. 1 shows the microscope pictures of the films of the modified PEDOT: PSS sample obtained in example 3, the conventional DMSO secondarily-doped PEDOT: PSS sample and the commercial PEDOT: PSS (4083) sample after spin coating. PSS film with the single DMSO added secondary doping modification has poor continuity and uniformity, and the DMSO secondary doping modification can weaken the film forming property of the dispersion. After a novel post-treatment modification method combining DMSO secondary doping modification and dialysis technology is adopted, the defect of the traditional single post-treatment mode is effectively overcome, and the PEDOT/PSS film surface is continuous and uniform.

FIG. 2 shows the atomic force microscope photographs of the modified PEDOT: PSS sample obtained in example 3, the conventional DMSO double-doped PEDOT: PSS sample, and the commercial PEDOT: PSS (4083) sample after spin coating. It can be seen from the figure that the surface roughness value (RMS) of the PEDOT: PSS sample is increased with a single DMSO addition of the second doping modification. After a novel post-treatment modification method combining DMSO (dimethyl sulfoxide) addition secondary doping modification and a dialysis technology is adopted, the RMS (root mean square) value of the surface of the PEDOT/PSS film is remarkably reduced.

FIG. 3 shows the I-V curves of spin-coated samples of modified PEDOT: PSS, conventional DMSO double-doped PEDOT: PSS and commercial PEDOT: PSS (4083) obtained in example 3 of the present invention. The conductivity of the samples was calculated to be 6.75X 10^-4,2.92×10^-3,1.49×10^-3S cm^-1(the order of the section heads is corresponded); PSS conductivity PEDOT < modified PEDOT obtained in example 3 PSS samples < DMSO modified PEDOT: PSS. The results show that the method of combining the secondary dopant addition modification and the dialysis technology effectively solves the problem of the trade-off between film forming property and conductivity in the traditional single post-treatment mode, and realizes the synchronous promotion of the conductivity and the film forming property (namely, uniformity and smoothness), so that the novel post-treatment modified PEDOT: PSS has higher application potential in organic photoelectric devices.

PSS samples of the modified PEDOT obtained in example 3 were used as hole transport materials for testing the application performance of organic photovoltaic devices.

The device structure is as follows: ITO/modified PEDOT obtained in example 3: PSS sample/PBDB-T: ITIC/PDINO/Al. Wherein PBDB-T represents poly ([2,6-4, 8-bis- ((2-ethylhexyl) -thiophen-5-yl) benzo [1, 2-B; PBDB-T, poly ([2,6' -4, 8-bis- ((2-ethylhexyl) -thiophen-5-yl) benzene chemical book [1, 2-B; 3,3-B ] dithiophene ] -ALT- [1, 3-bis- (thiophen-5-yl) -5, 7-bis- (2-ethylhexyl) benzo [1,2-C:4,5-C ' ] dithiophene-4, 8-dione ]), ITIC represents 2,2' - [ [6, 6, 12, 12-tetrakis (4-hexylphenyl) -6), 12-dihydrodithio [2, 3-d: 2', 3' -d ' ] -s-indono [1, 2-b: 5, 6-b ' ] dithiophene-2, 8-diyl ] bis [ methylene (3-oxo-1H-indene-2, 1(3H) -dimethylene) ] ] bis [ propylamine ], PDINO denotes 3,3' - (1,3,8, 10-tetraanthrone [2,1,9-DEF:6,5,10-D ' E ' F ' ] bisisoquinoline-2, 9(1H,3H,8H,10H) -diyl) bis (N, N-dimethylpropane-1-amine oxide).

A device manufacturing step: the preparation method comprises the following steps of ultrasonically cleaning Indium Tin Oxide (ITO) glass for 15min by using deionized water, a detergent, the deionized water, acetone and ethanol at one time, treating the glass for 10min by using ultraviolet ozone, then spin-coating a novel doping modified PEDOT: PSS (4083) solution at the rotating speed of 4000rpm, annealing the glass for 10min at 160 ℃, then spin-coating a PBDB: ITIC active layer material in a glove box, annealing the glass for 10min at 100 ℃, then spin-coating a PDINO solution (3000rpm, 0.1% wt), finally transferring the glass into a high vacuum chamber, and evaporating an aluminum electrode at the speed of 0.2nm/s to obtain an organic photovoltaic device, wherein the DMSO is used for adding the modified PEDOT: PSS and the PEDOT: PSS as references. The results of the photoelectric property test of the obtained device are shown in table 1.

TABLE 1

From the results in table 1, it can be seen that the energy conversion efficiency of the modified PEDOT to PSS device with DMSO addition is lower than that of the PEDOT to PSS device, and the energy conversion efficiency of the modified PEDOT to PSS device obtained in example 3 is higher than that of the PEDOT to PSS device. The results show that while the conductivity of PEDOT and PSS is improved by the traditional single post-treatment modification method, the film forming property of PEDOT and PSS is damaged, and the performance of an organic photoelectric device assembled by taking the PEDOT and PSS as a hole transport material is limited. According to the invention, a mode of combining secondary dopant addition modification and dialysis technology is adopted, so that the conductivity of PEDOT (PSS) and the film-forming property are synchronously improved, and the performance of the organic photoelectric device is greatly improved.

Example 4

To 19g of PEDOT: PSS dispersion was added 1g of sulfuric acid and stirred at room temperature at 200rpm for 12 h. And then dialyzing for 30min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid.

Example 5

To 19g of PEDOT: PSS dispersion was added 1g of perfluorooctanoic acid and stirred at room temperature at 200rpm for 12 hours. And then dialyzing for 90min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid.

Example 6

To 19g of PEDOT: PSS dispersion was added 1g of ethylene glycol and stirred at room temperature at 200rpm for 12 h. And then dialyzing for 20min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid. After spin coating, the obtained film has high continuity and uniformity, the conductivity of the film is higher than that of PEDOT PSS, namely 1.36 multiplied by 10^-3S cm^-1。

Example 7

To 19g of PEDOT: PSS dispersion, 1g of a mixed solution of ethylene glycol/DMSO (1:1) was added, and the mixture was stirred at room temperature at 200rpm for 12 hours. And then dialyzing for 30min by using a dialysis bag with the molecular weight cutoff of 1000Da to obtain the novel post-treatment modified PEDOT/PSS dispersion liquid. After spin coating, the obtained film has high continuity and uniformity, the conductivity of the film is higher than that of PEDOT PSS, namely 1.61 multiplied by 10^-3S cm^-1。

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they fall within the scope of the claims of the present invention.