A method for regulating the aggregation state of polymer semiconductor solutions and its application in the preparation of optoelectronic devices

Abstract

The present invention provides a method for regulating the aggregation state of a polymer semiconductor solution and its application in the preparation of optoelectronic devices. The method comprises the following steps: adding a strongly polar Lewis acid additive to a polymer semiconductor solution, regulating the molecular-scale aggregation state assembly characteristics of the polymer semiconductor solution without affecting the performance of the polymer semiconductor, thereby facilitating the preparation of a large-area uniform thin film from the polymer solution at room temperature. The present invention adopts a strongly polar Lewis acid to achieve the regulation of D-A type polymers containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI through a reversible protonation reaction, thereby achieving the effect of eliminating the gelation phenomenon or improving the solubility. Based on the viscosity-adjusted polymer solution, a variety of conventional film-forming methods can be used to achieve the preparation of a large-area uniform thin film, ultimately achieving the production of high-quality and uniform polymer thin film transistors.

Description

Technical Field

[0001] The present invention belongs to the field of polymer semiconductor organic optoelectronic materials and devices, and specifically relates to a method for regulating the aggregation state of a polymer semiconductor solution and its application in the preparation of optoelectronic devices. That is, a highly polar Lewis acid additive is used to achieve molecular-scale aggregation state assembly characteristics regulation of the polymer semiconductor solution to eliminate the gelation phenomenon of the polymer semiconductor solution or improve its solubility characteristics, and the method is applied in the production of optoelectronic devices and circuits. Background Art

[0002] Organic polymer semiconductor technology, originating in the 1970s, has developed rapidly. As an effective supplement to traditional silicon-based semiconductor technology, organic semiconductors have inherent advantages in molecular design and synthesis, large-area printing, and other aspects. Currently, the field-effect electron mobility or hole mobility of polymer semiconductor materials designed and synthesized based on donor-acceptor (DA) structures has exceeded 0.1 cm 2 V -1 s -1 , meeting the requirements of circuit applications (Ran K, Amegadze P, Kang I, et al. Advanced Functional Materials, 2013, 23, 5719-5727; Eckstein BJ, Melkonyan F.S., Wang G., et al. Advanced Functional Materials. 2021, 31, 2009359). Field-effect transistor devices based on polymer semiconductors have realized a variety of functional application circuits such as sensing, detection, electronic skin, and display driving (Yang JC, Mun J., Kwon SY, et al. Advanced Materials, 2019, 31, e1904765; Ersman PA, Lassnig R., Strandberg J., et al. Nature Communications, 2019, 10, 5053), injecting new impetus into the development of the next generation of electronics industry.

[0003] In addition to the design and synthesis of high-performance materials, the preparation of large-area circuits based on polymer semiconductor materials currently faces numerous challenges. For the preparation of printed circuits, ink stability and efficient uniform film formation technology are the biggest bottlenecks (Mizukami M., Cho SI, Watanabe K., et al. IEEE Electron Device Letters, 2017, 39, 39-42). The stability of the ink mainly depends on the solubility of the material and its supramolecular assembly properties. High-performance DA polymer semiconductors generally have obvious solution-state aggregation and assembly characteristics, resulting in poor ink stability (Zheng, YQ, Yao, ZF, Lei, T., et al. Adv. Mater. 2017, 29, 1701072). In addition, high-performance DA-type polymer semiconductors generally achieve good solubility and corresponding device performance only in highly toxic halogenated solvents (such as chlorobenzene, o-dichlorobenzene, and chloronaphthalene), while poor solubility and ink stability are common in non-halogenated green solvents (such as toluene, xylene, and mesitylene) (Cho J., Yu SH, Chung DS, Journal of Materials Chemistry C, 2017, 5, 2745-2757l). To address the above issues, currently developed methods include: improving the solubility of polymer semiconductors through side chain modification or random copolymerization strategies; reducing molecular weight to balance solubility and material properties (Yun HJ, Cho J., Chung DS, et al. Macromolecules 2014, 47, 7030); and using high-temperature processes to achieve thin film deposition (Yao ZF, Wang ZY, Wu HT, et al. Angew Chem Int Ed Engl 2020, 59, 17467). For the first two methods, the more complex design and corresponding synthesis steps are not conducive to ensuring the batch stability of the materials; for the high-temperature ink treatment method for device preparation, the temperature will affect the assembly of polymer semiconductors and the final film morphology, and high-temperature treatment is not conducive to the printing preparation of large-area uniform films.Therefore, for the existing high-performance polymer semiconductors with good batch stability (such as diketopyrrolidine (DPP) polymers, Liu Q., Bottle S.E., Sonar P., Advanced Materials 2020, 32, e1903882; isoindigo (IID) polymers, Lei T., Dou J., Ma Z., et al. Journal of the American Chemical Society. 2012, 134, 49, 20025–20028; naphthalimide (NDI) polymers, Chen Z., Zhang W., Huang J., et al. Macromolecules 2017, 50, 16, 6098–6107), it is very important to develop efficient and universal methods to improve the stability of polymer semiconductor inks at room temperature for the preparation of large-area thin films. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for regulating the molecular-scale aggregation assembly characteristics and inter-molecular chain interaction forces of DA-type polymer semiconductor solutions of heterocyclic receptors containing tertiary amines such as DPP, IID, and NDI, which exhibit gelation or poor solubility at room temperature, so as to increase the solubility of such polymer semiconductors in non-chlorine solvents and achieve stable gel-free semiconductor polymer inks, thereby applying them to the preparation of large-area circuits of optoelectronic devices.

[0005] The method for regulating the aggregation state of a polymer semiconductor solution and the interaction force between molecular chains provided by the present invention is: regulating the assembly behavior between polymer molecular chains in the solution state of the polymer semiconductor through a reversible protonation reaction.

[0006] Wherein, the polymer semiconductor can be a DA type polymer containing a tertiary amine heterocyclic receptor of the DPP type, IID type, or NDI type.

[0007] Specifically, the polymer semiconductor can be selected from PDVT-C10 (poly-3,6-dithiophen-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylethiophene-2,5-diyl); PDVT-C8 (poly-3,6-dithiophen-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4 -diketo-alt-thienylvinylthiophene-2,5-diyl); PDPP-3T(poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPPTPT(poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPP-BTT (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithieno[ 3,2-b]thiophene-5,5'-diyl-alt-thiophene-2,5-diyl}); PNFDTE (poly{bis-(2-octylnaphthalimide)-alt-(2-fluorothiophene)-ethylene-(2-fluorothiophene)-2,5-diyl}); PIID2T (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl});

[0008] Specifically, the method for regulating the aggregation state of a polymer semiconductor solution provided by the present invention is: adding a strongly polar Lewis acid additive to the polymer semiconductor solution, and regulating the molecular-scale aggregation state assembly characteristics of the polymer semiconductor solution without affecting the performance of the polymer semiconductor, thereby facilitating the preparation of large-area uniform thin films from the polymer solution at room temperature.

[0009] Wherein, the polymer semiconductor solution is a solution prepared by dissolving a polymer semiconductor in at least one solvent selected from toluene, chlorobenzene, chloroform and xylene;

[0010] The concentration of the polymer semiconductor solution may be 2 to 20 mg / mL; specifically, 6 to 10 mg / mL;

[0011] The highly polar Lewis acid may be trifluoroacetic acid (TFAA), dichloroacetic acid (DCAA), or a mixture of the two;

[0012] The amount of the strongly polar Lewis acid added may be 0.2% to 0.5%, based on 100% by volume of the solvent;

[0013] The present invention also provides a stable semiconductor polymer ink in a gel-free state.

[0014] The stable gel-free semiconductor polymer ink provided by the present invention is prepared by a method comprising the following steps: adding a strongly polar Lewis acid to a polymer semiconductor solution, thereby adjusting the molecular scale aggregation state of the polymer semiconductor solution to a gel-free state, thereby obtaining a stable gel-free semiconductor polymer ink.

[0015] The polymer semiconductor may be a DA-type polymer semiconductor, specifically a DPP-type, IID-type, or NDI-type DA-type polymer containing a tertiary amine heterocyclic receptor.

[0016] Specifically, the polymer semiconductor can be selected from PDVT-C10 (poly-3,6-dithiophen-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylethiophene-2,5-diyl); PDVT-C8 (poly-3,6-dithiophen-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4 -diketo-alt-thienylvinylthiophene-2,5-diyl); PDPP-3T(poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPPTPT(poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPP-BTT (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithieno[ 3,2-b]thiophene-5,5'-diyl-alt-thiophene-2,5-diyl}); PNFDTE (poly{bis-(2-octylnaphthalimide)-alt-(2-fluorothiophene)-ethylene-(2-fluorothiophene)-2,5-diyl}); PIID2T (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl});

[0017] The polymer semiconductor solution is a solution prepared by dissolving a polymer semiconductor in at least one solvent selected from toluene, chlorobenzene, chloroform and xylene;

[0018] The concentration of the polymer semiconductor solution may be 2 to 20 mg / mL; specifically, 6 to 10 mg / mL;

[0019] The highly polar Lewis acid may be trifluoroacetic acid (TFAA), dichloroacetic acid (DCAA), or a mixture of the two;

[0020] The addition amount of the strong polar Lewis acid may be 0.2% to 0.5%, based on 100% by volume of the solvent.

[0021] The application of strongly polar Lewis acids in the regulation of the aggregation state of DA-type polymer solutions containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI also falls within the scope of protection of the present invention.

[0022] The above-mentioned method for regulating the aggregation state of DA-type polymer solutions containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI, that is, the method for regulating the viscosity of DA-type polymer solutions containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI, or the application of the above-mentioned stable gel-free semiconductor polymer ink in the preparation of organic optoelectronic devices falls within the scope of protection of the present invention.

[0023] In the application, the organic photoelectric device may specifically be a polymer thin film transistor.

[0024] The present invention also provides a method for preparing large-area polymer thin film transistors based on the DA-type polymer semiconductor solution containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI optimized by the above-mentioned aggregation state regulation technology.

[0025] The method for preparing large-area polymer thin film transistors based on the DPP, IID, NDI, or other tertiary amine heterocyclic receptor-containing DA-type polymer semiconductor solution optimized by the above-mentioned aggregation state control technology comprises the following operations:

[0026] 1) Preparing source and drain electrodes on a substrate;

[0027] 2) modifying OTS on the source and drain electrodes prepared in step 1);

[0028] 3) preparing a polymer semiconductor layer on the OTS modified layer prepared in step 2);

[0029] 4) preparing a dielectric layer on the semiconductor layer prepared in step 3);

[0030] 5) A gate electrode is prepared on the dielectric layer prepared in step 4) to obtain a polymer thin film transistor device.

[0031] In the above method, the device structure is a top-gate bottom-contact structure;

[0032] In the above step 1), the substrate may be a glass substrate, PET, PI or PEN substrate;

[0033] Before use, the substrates were ultrasonically cleaned with toluene, secondary water, acetone, and isopropanol in sequence;

[0034] The source electrode and the drain electrode are selected from gold, carbon nanotubes, etc., preferably gold;

[0035] The preferred method for preparing the source electrode and drain electrode is vacuum evaporation or photolithography combined with magnetron sputtering;

[0036] The thickness of the source electrode and the drain electrode is 20 to 40 nm, specifically 30 to 35 nm;

[0037] In step 2), an OTS (octadecyltrichlorosilane) modification layer is prepared by a vapor phase modification method. The specific operation steps are as follows: a small amount of OTS (about 1 fL) is applied to the substrate after oxygen plasma cleaning, and then the substrate is placed in a vacuum oven with a true vacuum degree of 0.01 Pa, and then heated to 120° C. and maintained for 3 hours, and then naturally cooled to room temperature to complete the modification process;

[0038] In the step 3), the method for preparing the polymer semiconductor layer can be a spin coating method, a film pulling method, a solution shearing method or a roll-to-roll imprinting method; the solution used is a DA-type polymer semiconductor solution containing a tertiary amine heterocyclic receptor such as DPP, IID, or NDI, to which 0.2vt%-0.5vt% TFAA and / or dichloroacetic acid (DCAA) additives are added;

[0039] Specifically, spin coating and solution shear film forming methods are preferred. In the spin coating method, the spin coating speed is generally 2000-4000 rad / min, the spin coating time is generally 40-60s, preferably 3000-3500 rad / min, and the spin coating time is 40-50s; in the spin coating, the spin coating solution used is preferably a 6 mg / mL PDVT-10 polymer semiconductor solution with 0.2vt% TFAA additive added, the solvent can be o-xylene, the spin coating speed can be 3500 rad / min, the spin coating time can be 50min, and the annealing conditions after spin coating can specifically be 10min 120°C; the thickness of the polymer semiconductor layer is 25-30nm; in the shear film drawing method, the shear film drawing speed is 10-30mm / s, the shear angle is 6°-15°, the distance between the substrate and the scraper is 50μm-200μm, and the substrate temperature is 60°C-120°C. The preferred shearing and film drawing speed is 14-20 mm / s, the shearing angle is 6°-8°, the distance between the substrate and the scraper is 80 μm-100 μm, and the substrate temperature is 60°C-100°C.

[0040] In the step 4), the preparation method is spin coating or solution shearing; specifically, the molecular weight of the polymethyl methacrylate (PMMA) polymer is 12 to 100W, the solvent can be n-butyl acetate, the solution concentration can be 50 to 70 mg / mL, and the specific conditions of the spin coating method are: the solution concentration is 60 to 70 mg / mL (PMMA 996w), the spin coating speed can be 2000 to 3000 rad / min, and the spin coating time can be 40 to 60 s, preferably the spin coating speed is 2000 to 2500 rad / min, and the spin coating time is 50 to 60 s; annealing is performed after spin coating, and the conditions for annealing after spin coating can be specifically 30 minutes and 90°C; the thickness of the dielectric layer can be 700 to 900 nm; specifically 750 to 850 nm; the specific conditions for solution shearing are: the solution concentration is 60 to 70 mg / mL (PMMA 35w), the speed of shearing and pulling the film is 4-8mm / s, the shearing angle is 8-15°, the distance between the substrate and the scraper is 100-200μm, and the substrate temperature is 60℃.

[0041] In the step 5), the gate electrode is made of metal aluminum; the gate electrode is prepared by vacuum evaporation; the evaporation conditions are as follows: the vacuum degree is 10 -4 ~10 -7 Pa, preferably 4 to 8 × 10 -5 Pa; the evaporation rate is Preferred More specifically, the evaporation rate for the first 10nm is The following part is

[0042] The present invention discloses a highly efficient and universal polymer solution aggregation state control technology for DA-type polymer solutions containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI, and its application in the production of organic optoelectronic devices. The present invention uses a highly polar Lewis acid to achieve control of DA-type polymers containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI through a reversible protonation reaction, thereby eliminating the gelation phenomenon or improving solubility. Based on the viscosity-adjusted polymer solution, a variety of conventional film-forming methods can be used to prepare large-area uniform thin films, ultimately achieving the production of high-quality and uniform polymer thin-film transistors. At the same time, this technology can also be applied to other optoelectronic devices, thereby realizing low-energy, high-performance optoelectronic devices and promoting the application of polymer semiconductor materials in integrated electronic circuits, flexible sensors, electronic skin and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1Schematic diagram of the protonation reaction between the highly polar Lewis acid additive and the DPP polymer semiconductor used in the present invention, a comparison of the fluidity of the PDVT-10 polymer semiconductor solution before and after the addition of TFEA in Example 1, and a comparison of the optical microscopy results of the corresponding thin films prepared by the spin coating method based on the above two solutions.

[0044] Figure 2 This is a comparison chart of the peak force tapping mode atomic force microscope film surface height imaging results of the PDVT-10 polymer semiconductor film prepared by spin coating in Example 1 of the present invention and Comparative Example 1.

[0045] Figure 3 Schematic diagram of the device structure of a thin film transistor (a), and transfer characteristic curves of the polymer thin film transistors prepared in Example 1 of the present invention and Comparative Example 1 (b), Transfer curve of polymer field-effect transistor prepared based on hot pristine PDVT-C10 solution; Figure 3 is the transfer curve of a polymer field-effect transistor prepared based on a 0.2% (volume ratio to solvent) TFAA-doped PDVT-C10 solution.

[0046] Figure 4 Comparison results of transfer characteristic curves of polymer thin film transistors at five different positions on a 5 cm×5 cm substrate prepared in Example 2 of the present invention and Comparative Example 2 (where (1) is the transfer curve of a polymer field effect transistor prepared based on a 0.2% (volume ratio with solvent) TFAA-doped PDVT-C10 solution; (2) is the transfer curve of a polymer field effect transistor prepared based on a hot original PDVT-C10 solution); (3) transfer characteristic curves of OFET devices corresponding to PDVT-10 of different thicknesses.

[0047] Figure 5 (1) Comparison of the fluidity of the PDPP-DTT solutions of Example 3 of the present invention and Comparative Example 3 with or without TFAA (left figure); and (2) Comparison of the transfer characteristic curves of polymer thin film transistors prepared based on the above two solutions, wherein Transfer curve of polymer field-effect transistor prepared with 0.2% (volume ratio with solvent) TFAA-doped PDPP-DTT solution; Transfer curve of the polymer field-effect transistor prepared based on the hot original PDPP-DTT solution. DETAILED DESCRIPTION

[0048] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0049] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0050] The present invention provides a method for regulating the aggregation state of a polymer semiconductor solution and the interaction force between molecular chains, which comprises regulating the assembly behavior between polymer molecular chains in the solution state of the polymer semiconductor through a reversible protonation reaction.

[0051] The polymer semiconductor may be a DA-type polymer semiconductor, specifically a DPP-type, IID-type, or NDI-type DA-type polymer containing a tertiary amine heterocyclic receptor.

[0052] Specifically, the polymer semiconductor can be selected from PDVT-C10 (poly-3,6-dithiophen-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylethiophene-2,5-diyl); PDVT-C8 (poly-3,6-dithiophen-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4 -diketo-alt-thienylvinylthiophene-2,5-diyl); PDPP-3T(poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPPTPT(poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPP-BTT (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithieno[ 3,2-b]thiophene-5,5'-diyl-alt-thiophene-2,5-diyl}); PNFDTE (poly{bis-(2-octylnaphthalimide)-alt-(2-fluorothiophene)-ethylene-(2-fluorothiophene)-2,5-diyl}); PIID2T (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl});

[0053] Specifically, the method for regulating the aggregation state of a polymer semiconductor solution provided by the present invention is: adding a strongly polar Lewis acid additive to the polymer semiconductor solution, and regulating the molecular-scale aggregation state assembly characteristics of the polymer semiconductor solution without affecting the performance of the polymer semiconductor, thereby facilitating the preparation of large-area uniform thin films from the polymer solution at room temperature.

[0054] Wherein, the polymer semiconductor solution is a solution prepared by dissolving a polymer semiconductor in at least one solvent selected from toluene, chlorobenzene, chloroform and xylene;

[0055] The concentration of the polymer semiconductor solution may be 2 to 20 mg / mL; specifically, 6 to 10 mg / mL;

[0056] The highly polar Lewis acid may be trifluoroacetic acid (TFAA), dichloroacetic acid (DCAA), or a mixture of the two;

[0057] The amount of the strongly polar Lewis acid added may be 0.2% to 0.5%, based on 100% by volume of the solvent;

[0058] The present invention also provides a stable semiconductor polymer ink in a gel-free state.

[0059] The stable gel-free semiconductor polymer ink provided by the present invention is prepared by a method comprising the following steps: adding a strongly polar Lewis acid to a polymer semiconductor solution, thereby adjusting the molecular scale aggregation state of the polymer semiconductor solution to a gel-free state, thereby obtaining a stable gel-free semiconductor polymer ink.

[0060] The application of the above-mentioned method for regulating the aggregation state of DA-type polymer solutions containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI, that is, the method for regulating the viscosity of DA-type polymer solutions containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI in the preparation of organic optoelectronic devices falls within the scope of protection of the present invention.

[0061] In the application, the organic photoelectric device may specifically be a polymer thin film transistor.

[0062] The present invention also provides a method for preparing large-area polymer thin film transistors based on the DA-type polymer semiconductor solution containing tertiary amine heterocyclic receptors such as DPP, IID, and NDI optimized by the above-mentioned aggregation state regulation technology.

[0063] The method for preparing large-area polymer thin film transistors based on the DPP, IID, NDI, or other tertiary amine heterocyclic receptor-containing DA-type polymer semiconductor solution optimized by the above-mentioned aggregation state control technology comprises the following operations:

[0064] 1) Preparing source and drain electrodes on a substrate;

[0065] 2) modifying OTS on the source and drain electrodes prepared in step 1);

[0066] 3) preparing a polymer semiconductor layer on the OTS modified layer prepared in step 2);

[0067] 4) preparing a dielectric layer on the semiconductor layer prepared in step 3);

[0068] 5) A gate electrode is prepared on the dielectric layer prepared in step 4) to obtain a polymer thin film transistor device.

[0069] In the above method, in step 3), the method for preparing the polymer semiconductor layer can be spin coating, film pulling, solution shearing or roll-to-roll imprinting; specifically, spin coating and solution shearing are preferred. In the spin coating method, the spin coating speed is generally 2000-4000 rad / min, the spin coating time is generally 40-60s, preferably the spin coating speed is 3000-3500 rad / min, and the spin coating time is 40-50s; in the spin coating, the spin coating solution used is preferably a 6 mg / mL PDVT-10 polymer semiconductor solution with 0.2vt% TFAA additive added, the solvent can be o-xylene, the spin coating speed can be 3500 rad / min, the spin coating time can be 50min, and the annealing conditions after spin coating can specifically be 10min 120°C; the thickness of the polymer semiconductor layer is 25-30nm; in the shear film drawing method, the shear film drawing speed is 10-30mm / s, the shear angle is 6°-15°, the distance between the substrate and the scraper is 50μm-200μm, and the substrate temperature is 60°C-120°C. The preferred shearing and film drawing speed is 14-20 mm / s, the shearing angle is 6°-8°, the distance between the substrate and the scraper is 80 μm-100 μm, and the substrate temperature is 60°C-100°C.

[0070] Because the selected materials and fabricated devices are not sensitive to water and oxygen, the electrical performance of the polymer thin-film transistors tested in this invention is the same when tested in air and nitrogen atmospheres. Unless otherwise specified, the film preparation and testing involved in the examples were conducted under laboratory air conditions.

[0071] The synthetic route of polymer PDVT-10 was referred to the literature (Chen HJ, Guo YL, Yu G., et al. Advanced Materials 2012, 24, 4589-4589).

[0072] Within a certain time scale (48 hours according to the research results in the literature), the polymer of PDVT-10 increases with time, and the molecular weight increases accordingly. The larger the molecular weight of PDVT-10, the more serious the gelation phenomenon in the solution. In order to better illustrate the role of the strong polar Lewis acid additive in regulating the solution aggregation state and eliminating the gelation phenomenon in the present invention, the polymerization time of PDVT-C10 selected in the examples of the present invention is controlled to 24 hours, and the corresponding polymer number average molecular weight (M n)=73.5kDa, weight average molecular weight (M w )=112kDa.

[0073] The specific synthetic route of polymer PDVT-10 is:

[0074] The target polymer was prepared by a well-established method of coupling brominated monomers with tin reagents. The synthesis of the monomers 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-decyltetradecyl)pyrrolo[3,4c]pyrrole-1,4-dione and 1,2-(E)-bis(5′-trimethyltin-2′-C-thienyl)ethylene followed the standard synthesis procedure (Chen HJ; Guo YL; Yu G; et al. Advanced Materials 2012, 24, 4589-4589).

[0075] The synthesis steps of the target product PDVT-C10 are as follows:

[0076] To a 50 mL three-necked flask, 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-decyltetradecyl)pyrrolo[3,4-c]pyrrole-1,4-dione (305 mg, 0.3 mmol), 1,2-(E)-bis(5′-trimethyltin-2′-C-thienyl)ethylene (155 mg, 0.3 mmol), Pd2(dba)3 (9 mg), P(o-tol)3 (15 mg), and 5 mL of chlorobenzene were added in sequence. Under nitrogen, the reaction was refluxed at 120°C for 24 h before quenching. The cooled reaction mixture was poured into 200 mL of methanol containing 15 mL of concentrated hydrochloric acid for precipitation and filtered to obtain the crude polymer. The polymer was then extracted with methanol, acetone, n-hexane, dichloromethane, and chlorobenzene. Finally, the obtained chlorobenzene solution was dried to obtain 0.34 g of black solid polymer product with a yield of 95% and a number average molecular weight (M n )=73.5kDa, weight average molecular weight (M w )=112kDa, molecular weight distribution index (PDI)=1.58.

[0077] Example 1

[0078] In this embodiment, a PDVT-10 polymer solution adjusted with 0.2vt% of TFAA additive is used as a semiconductor material, and a polymer thin film transistor is prepared according to the following steps.

[0079] 1) A transparent 2 cm × 2 cm polyimide (PI) substrate was ultrasonically cleaned in toluene, water, acetone, and isopropyl alcohol, followed by purging with high-purity nitrogen to remove the solvent.

[0080] 2) Vacuum thermal evaporation was used to prepare source and drain electrodes on the clean substrate described in step (1), wherein the thickness of the gold electrode was 30 nm, and the length and width of the channel were 50 μm and 4500 μm respectively. The specific vacuum evaporation parameters were: the vacuum degree was controlled at 6×10 -6 Tor below, the evaporation rate is

[0081] 3) An OTS modified layer was prepared on the electroded PI substrate of (2) using a vapor phase modification method. The vapor phase conditions for OTS modification were as follows: a small amount of OTS (about 1 fL) was applied to the substrate after oxygen plasma cleaning, and then the substrate was placed in a vacuum oven with a true vacuum degree of 0.01 Pa, and then heated to 120°C and maintained for 3 hours, and then naturally cooled to room temperature to complete the modification process;

[0082] 4) A polymer semiconductor layer was prepared on the OTS-modified substrate of step (3) by spin coating. The PDVT-10 solution containing the TFAA additive was prepared as follows: pure PDVT-10 solid was added to a certain amount of o-xylene solvent, and the solution was heated at 90° C. for 24 hours to obtain a dissolved polymer solution. The solution was naturally cooled to room temperature, and then a certain amount of TFEA was added according to a volume ratio. The mixture was stirred at room temperature for 3 hours to obtain the target solution.

[0083] The conditions for preparing the polymer semiconductor layer were: 6 mg / mL PDVT-10 solution, o-xylene as solvent, 0.2% TFAA, a spin coating speed of 3500 rad / min, and a spin coating time of 50 seconds. The prepared polymer semiconductor film was annealed at 120°C for 10 minutes to obtain a 25 nm thick polymer semiconductor layer. Figure 1 Schematic diagram of the protonation reaction between the highly polar Lewis acid additive and the DPP polymer semiconductor used in the present invention, a comparison of the fluidity of the PDVT-10 polymer semiconductor solution before and after the addition of TFEA, and a comparison of the optical microscopy results of the corresponding thin films prepared by the spin coating method based on the above two solutions;

[0084] 5) preparing a dielectric layer on the polymer semiconductor layer of step (4) by spin coating. The spin coating liquid is a 60 mg / mL PMMA (molecular weight 99.6W) solution, the solvent is n-butyl acetate, the spin coating speed is 2000 rad / min, the spin coating time is 50 s, and the preparation is completed. After annealing at 90°C for 30 minutes, a dielectric layer with a thickness of 850 nm is obtained;

[0085] 6) A 100 nm thick aluminum gate electrode was prepared on the device containing the dielectric layer prepared in step (5) by vacuum evaporation to complete the device preparation process. The vacuum degree of vacuum evaporation was 6×10 -6 Tor; the evaporation rate is controlled at the beginning of 10nm Later control

[0086] The structure of the polymer thin film transistor obtained in this embodiment is as follows, specifically comprising a substrate 1, a source-drain electrode 2 located on the substrate,

[0087] The OTS modified layer 3 located on the source electrode and the drain electrode,

[0088] The polymer semiconductor layer 4 is located on the OTS modified layer,

[0089] A dielectric layer 5 located on the polymer semiconductor layer after the patterning technique,

[0090] A gate electrode 6 located on the dielectric layer,

[0091] The above OFET device is a top-gate bottom-contact device structure, and the structural diagram is shown in FIG. Figure 3 shown.

[0092] Comparative Example 1

[0093] The same preparation method as in Example 1 was followed, except that the additives in the polymer PDVT-10 solution were removed. Meanwhile, the temperature of the solution was maintained at 90° C. to maintain the fluidity of the solution.

[0094] By comparing the transfer characteristic curves of the polymer thin film transistor in Example 1 and Comparative Example 1 ( Figure 3 ) It can be seen that the introduction of TFAA additives can effectively eliminate the gelation phenomenon of the polymer solution, so that it can be spin-coated to prepare semiconductor thin films at room temperature, and obtain the same field effect performance as the OFET device prepared by the original solution that relies on high temperature heating to eliminate the gelation phenomenon. Figure 2 The surface morphology comparison shows that the addition of TFAA does not change the stacking morphology of PDVT-10. Figure 3 The transfer characteristic curves of the OFET device prepared by adding TFAA additive can be compared with those of the OFET device prepared by adding TFAA additive. The mobility of the OFET device prepared by adding TFAA additive can still be maintained at 0.48~0.52cm 2 V -1 s -1 , the off-state current is kept at 8×10 -8 A to 1×10 -9 A, the threshold voltage is maintained between -8V and -2V.

[0095] Example 2

[0096] An OFET device was prepared in the same manner as in Example 1, except that the size of the corresponding substrate was enlarged to 5 cm × 5 cm, and the film preparation method in steps (4) and (5) was changed to a solution shearing method. The shearing preparation conditions of the semiconductor solution were optimized as follows: the semiconductor solution concentration was 10 mg / mL, the shearing film pulling speed was 18 mm / s, the shearing angle was 8°, the distance between the substrate and the scraper was 100 μm, and the substrate temperature was 60°C. The shearing preparation conditions of the dielectric layer solution were optimized as follows: the dielectric layer solution concentration was 65 mg / mL (PMMA 35w), the shearing film pulling speed was 6 mm / s, the shearing angle was 15°, the distance between the substrate and the scraper was 100 μm, and the substrate temperature was 60°C.

[0097] Five different locations on the substrate were selected to test the OFET performance to verify its film uniformity.

[0098] Comparative Example 2

[0099] An OFET device was prepared in the same manner as in Example 2, except that the additives in the polymer PDVT-10 solution were removed. After the solution was heated and dissolved at 90° C. for 24 h, the temperature was maintained at 60° C. to maintain the fluidity of the solution.

[0100] Five different locations on the substrate were selected to test the OFET performance to verify its film uniformity.

[0101] From the comparison results of the uniformity of the OFET devices of Example 2 and Comparative Example 2 ( Figure 4 ) As can be seen, the introduction of the TFAA additive effectively eliminates the solution's gelation at room temperature, resulting in better ink stability and the ability to produce relatively uniform semiconductor films at lower shear temperatures. However, the original polymer solution exhibits severe gelation, persisting even at 60°C. Consequently, variations in uniformity and thickness at different locations during film preparation are unavoidable, ultimately impacting device performance and the uniformity of multiple devices.

[0102] Example 3

[0103] The same preparation method as in Example 1 was used, except that the polymer was changed to PDPP-DTT, and other conditions remained the same.

[0104] Comparative Example 3

[0105] The same preparation method as in Comparative Example 1 was used, except that the polymer was changed to PDPP-DTT, and other conditions remained the same.

[0106] According to the OFET device results and fluidity comparison results of Example 3 and Comparative Example 3 ( Figure 5 ), which can illustrate the versatility of the method of the present invention for regulating the aggregation state of gel-like DPP solutions.

Claims

1. A method for regulating the aggregation state and inter-chain interaction forces of a polymer semiconductor solution, comprising: adding a strongly polar Lewis acid additive to the polymer semiconductor solution to regulate the molecular-scale aggregation assembly characteristics of the polymer semiconductor solution without affecting the performance of the polymer semiconductor, thereby facilitating the preparation of large-area uniform thin films from the polymer solution at room temperature; The polymer semiconductor is a DA type polymer containing a tertiary amine heterocyclic receptor of the DPP type, IID type, or NDI type; The highly polar Lewis acid is trifluoroacetic acid, dichloroacetic acid or a mixture of the two.

2. The method according to claim 1, wherein: The polymer semiconductor is selected from: PDVT-C10 (poly-3,6-dithiophen-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylethiophene-2,5-diyl); PDVT-C8 (poly-3,6-dithiophen-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione- alt-thiophenevinylthiophene-2,5-diyl); PDPP-3T (poly{2,2'-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5'-diyl-alt-thiophene-2,5-diyl}); PDPPTPT (poly{2,2'-[(2,5-bis(2-hexyldecyl)- PDPP-BTT (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithieno[3,2-b ]thiophene-5,5'-diyl-alt-thiophene-2,5-diyl}); PNFDTE (poly{bis-(2-octylnaphthalimide)-alt-(2-fluorothiophene)-ethylene-(2-fluorothiophene)-2,5-diyl}); PIID2T (poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl}).

3. The method according to claim 1 or 2, characterized in that: The polymer semiconductor solution is a solution prepared by dissolving a polymer semiconductor in at least one solvent selected from toluene, chlorobenzene, chloroform and xylene; The concentration of the polymer semiconductor solution is 2 to 20 mg / mL; The addition amount of the strong polar Lewis acid is 0.2% to 0.5%, based on 100 volume of the solvent.

4. A stable, gel-free semiconductor polymer ink, prepared by a method comprising the following steps: adding a strongly polar Lewis acid to a polymer semiconductor solution, thereby adjusting the molecular-scale aggregation state of the polymer semiconductor solution to a gel-free state, thereby obtaining a stable, gel-free semiconductor polymer ink; The polymer semiconductor is a DA type polymer containing a tertiary amine heterocyclic receptor of the DPP type, IID type, or NDI type; The highly polar Lewis acid is trifluoroacetic acid, dichloroacetic acid or a mixture of the two.

5. The semiconductor polymer ink according to claim 4, characterized in that: The polymer semiconductor solution is a solution prepared by dissolving a polymer semiconductor in at least one solvent selected from toluene, chlorobenzene, chloroform and xylene; The concentration of the polymer semiconductor solution is 2 to 20 mg / mL; The addition amount of the strong polar Lewis acid is 0.2% to 0.5%, based on 100 volume of the solvent.

6. Use of the method for regulating the aggregation state and inter-molecular chain interaction force of a polymer semiconductor solution according to any one of claims 1 to 3 or the stable gel-free semiconductor polymer ink according to claim 4 or 5 in the preparation of an organic optoelectronic device, wherein the organic optoelectronic device is a polymer thin film transistor.

7. A method for preparing a large-area polymer thin film transistor, comprising the following steps: 1) Preparing source and drain electrodes on a substrate; 2) modifying OTS on the source and drain electrodes prepared in step 1); 3) preparing a polymer semiconductor layer on the OTS modified layer prepared in step 2); 4) preparing a dielectric layer on the semiconductor layer prepared in step 3); 5) preparing a gate electrode on the dielectric layer prepared in step 4) to obtain a polymer thin film transistor device, in, In the step 3), the method for preparing the polymer semiconductor layer is spin coating, film pulling, solution shearing or roll-to-roll imprinting; The solution used is a DA type polymer semiconductor solution of DPP type, IID type, NDI type tertiary amine heterocyclic receptor-containing tertiary amine receptor added with 0.2vt%-0.5vt% TFAA and / or dichloroacetic acid additives.

8. A large-area polymer thin film transistor prepared by the method of claim 7, wherein the polymer semiconductor layer is made of a DA-type polymer solution of a DPP, IID, or NDI-type tertiary amine heterocyclic receptor-containing polymer after adjusting the aggregation state by adding a strongly polar Lewis acid.

9. Application of strong polar Lewis acids in the regulation of aggregation state of DA-type polymer solutions containing tertiary amine heterocyclic receptors of the DPP, IID, and NDI types; The highly polar Lewis acid is trifluoroacetic acid, dichloroacetic acid or a mixture of the two.

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