Doped structure for realizing high-performance stretchable electroluminescent polymer semiconductor thin film and application thereof

Abstract

This invention provides a doped structure for achieving high-performance stretchable electroluminescent polymer semiconductor thin films, simultaneously improving both the mechanical and semiconductor properties of the luminescent polymer semiconductor and enabling its application in stretchable optoelectronic devices. Specifically, a luminescent polymer semiconductor with a certain assembly capability (such as high molecular weight (L-SY-PPV)) is blended with PAN. The resulting hybrid film possesses a low-scale three-dimensional through-cell nanonetwork structure. This structure simultaneously balances the electroluminescent and mechanical properties of the luminescent polymer semiconductor. The nanoconfined structure film is uniformly distributed from top to bottom, with nanofibers ranging in size from 20 nm to 50 nm. The nanofibers and amorphous structures interpenetrate and stack, forming an interpenetrating network structure. Stretchable luminescent semiconductors based on this structure hold promise for use in novel flexible display applications.

Description

Technical Field

[0001] This invention belongs to the field of stretchable polymer semiconductor organic optoelectronic materials and devices, specifically involving a doped structure employing a low-scale three-dimensional through-nano network and its application in the fabrication of stretchable optoelectronic devices. Background Technology

[0002] Compared to traditional inorganic semiconductor materials, the main advantages of organic semiconductor materials lie in their molecular designability, low-cost, large-area solution processing capabilities, and intrinsic flexibility. Among organic semiconductors, polymer semiconductor materials exhibit greater potential and advantages in solution processing and flexible circuit applications compared to small organic molecules (Wang, GJ, Gasperini, A., Bao, ZN, Advanced Electronic Materials. 2018, 4, 1700429). In recent years, the optoelectronic properties of polymer semiconductors have seen significant advancements: the hole mobility and electron mobility of polymer semiconductors based on novel donor-acceptor structures both exceed 5 cm⁻¹. 2 V -1 s -1 This meets the requirements of circuit applications (Liu Q., Bottle S. E., Sonar P., Advanced Materials, 2020, 32, e1903882); the external quantum efficiency of delayed fluorescence polymer luminescent materials based on the donor-acceptor structure of space charge transfer structure exceeds 20%, far surpassing that of traditional homopolymer polymer luminescent materials (Shao S., Hu J., Wang X., et al. Journal of the American Chemical Society, 2017, 139, 17739). Through novel molecular structure design and thin film stacking structure adjustment, the mechanical properties of polymer semiconductors can be significantly improved while maintaining their inherent photoelectric properties, thereby realizing intrinsically stretchable optoelectronic devices based on polymer semiconductor materials (Zheng Y., Ashizawa M., Zhang S., et al. Chemistry of Materials, 2020, 32, 13, 5700-5714). The development of such materials and devices will become an important support for novel electronic skin and flexible circuits.

[0003] Currently, substantial progress has been made in the research of stretchable polymer semiconductor materials and devices. In terms of material design, the mechanical properties of polymer semiconductor materials have been improved by introducing flexible segments (Fumitaka S., Kleinschmidt AT, Kayser LV, et al. Macromolecules, 2018, 51, 15, 5944-5949), cross-linked side chains (Wang GJ, Zheng Y., Zhang S., et al. Chemistry of Materials, 2019, 31, 17, 6465-6475), and short-range ordered near-amorphous strategies (Zheng Y., Wang GN, Kang J., et al. Advanced Functional Materials, 2019, 29, 1905340; Jaewan M., Yuto O., Weichen W., et al. Naturecommunication, 2021, 12, 3572). In terms of device structure, nanoconfined structures based on elastomer doping (Xu J., Wang S., Wang G., et al. Science, 2017, 355, 59–64) and hybrid thin films based on assembled nanowires combined with amorphous structures (Choi D., Kim H., Persson N., et al. Chemistry of Materials, 2016, 28, 4, 1196–1204) have achieved simultaneous optimization of the semiconductor and mechanical properties of polymers. Compared to stretchable polymer semiconductor materials, the design, synthesis, and corresponding device research of stretchable light-emitting polymer semiconductor materials are still in the exploratory stage. On the one hand, the current design strategies for stretchable light-emitting polymer materials cannot simultaneously achieve semiconductor light-emitting properties and mechanical properties, resulting in the improvement of mechanical properties at the expense of semiconductor light-emitting performance (Duong, AN, Wu, CC, Li, YT, et al. Macromolecules, 2020, 53, 4030). 4037). On the other hand, due to the requirements of material stacking for luminescent properties, most existing high-performance luminescent polymer materials have poor assembly capabilities and cannot form assembled nanowire structures. Elastomer doping also significantly affects their charge transport capabilities, thus preventing the effective construction of stretchable electroluminescent devices through this strategy (Kim JH, Park JW, Science Advances, 2021, 7, eabd9715). To further improve the mechanical properties of luminescent polymer semiconductors and corresponding electroluminescent devices, it is crucial to develop novel stretchable luminescent semiconductor polymers and to develop new doping structure strategies based on existing high-efficiency luminescent polymer materials to achieve high-efficiency stretchable electroluminescent devices. Summary of the Invention

[0004] The purpose of this invention is to provide a doped structure for realizing high-performance stretchable electroluminescent polymer semiconductor thin films, so as to improve the mechanical properties of the light-emitting polymer semiconductor and enhance its electroluminescent properties, and apply it to the fabrication of stretchable optoelectronic devices.

[0005] This invention enhances the mechanical properties of light-emitting polymer semiconductors through a low-scale, three-dimensional, through-the-hole nanonetwork doped structure. This structure simultaneously achieves both the electroluminescent and mechanical properties of the light-emitting polymer semiconductor. Specifically, based on a light-emitting polymer semiconductor with suitable assembly capabilities (such as high-molecular-weight SY-PPV), a low-scale, three-dimensional, through-the-hole nanonetwork structure is formed by doping with highly polar polyacrylonitrile (PAN) or its copolymers. This allows for the regulation of the assembly capability and stacking morphology of the light-emitting polymer semiconductor, thereby realizing a high-performance, stretchable electroluminescent polymer film based on the light-emitting polymer semiconductor.

[0006] The light-emitting polymer semiconductor with suitable assembly capability generally has a high molecular weight and exhibits obvious assembly gelation phenomenon in solution.

[0007] The light-emitting polymer semiconductor with suitable assembly capability is selected from high molecular weight L-SY-PPV (poly[{2,5-di(3´,7´-dimethyloctoxy)-1,4-phenylacetylene}-co-{3-(4´-(3´,7´-dimethyloctoxy)phenyl)-1,4-phenylacetylene}-co-{3-(3´-(3´,7´-dimethyloctoxy)phenyl)-1,4-phenylacetylene}]), Regular MEH-PPV (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylacetylene](Regular)), PF-OPV (poly[(9,9-di-n-octylfluorenyl-2,7-phenyleneethylene)-alt-(2-methoxy-5-(2-ethylhexyloxy)-1,4-diyl)]), Regular-MDMO-PPV (poly[[2-[(3,7-dimethyloctyl)oxy]-5-methoxy)]) [-1,4-phenyl]-1,2-vinyldiyl](Regular)), CN-PPV (poly(2,5-di(hexyloxy)cyano-terephthalimide)), PmPV (poly[(m-phenylacetylene)-co-(2,5-dioctyloxy-terephthalimide)]), SPG-01T (spirocyclic polymer, Sigma-Aldrich), SPR-001 (PPV polymer, Sigma-Aldrich), preferably L-SY-PPV;

[0008] The molecular weight of the light-emitting polymer semiconductor with suitable assembly capability is between 420 kDa and 1950 kDa.

[0009] The luminescent polymer semiconductor material with suitable assembly capability is soluble in at least one of toluene, chlorobenzene, chloroform, and xylene; the concentration of the luminescent polymer semiconductor material can be 2~15 mg / mL; specifically, it can be 4~10 mg / mL.

[0010] The highly polar polyacrylonitrile (PAN) or its copolymer has a molecular weight of 150 kDa, preferably PAN;

[0011] The ratio of the light-emitting polymer semiconductor doped with polyacrylonitrile with suitable assembly capability is controlled at 0.4 to 3:1 (by mass), specifically 7:3, 5:5, 3:7; the specific optimal ratio is adjusted according to different light-emitting polymers.

[0012] After adding PAN, the gelation phenomenon of the solution of the light-emitting polymer semiconductor with suitable assembly capability disappears and the solution fluidity is enhanced, but the light-emitting properties are not affected.

[0013] The semiconductor thin film prepared based on the mixed solution of luminescent polymer semiconductor doped with acrylonitrile with suitable assembly capability has a low-scale three-dimensional through-nano network structure. Its typical features are: the nano network structure film is uniformly distributed from top to bottom, the nanofibers are between 20 nm and 50 nm in size, and the nanofibers and amorphous structures interpenetrate and stack to form an interpenetrating network structure.

[0014] The present invention also provides a method for preparing the above-mentioned stretchable electroluminescent polymer semiconductor thin film.

[0015] The method for preparing a stretchable electroluminescent polymer semiconductor film provided by the present invention includes the following steps: preparing the polymer semiconductor film on an octadecyltrichlorosilane-modified substrate by using a mixed solution of polyacrylonitrile or its copolymer and a light-emitting polymer semiconductor with suitable assembly capability;

[0016] The polymer semiconductor thin film can be prepared by spin coating, solution shearing, or roll-to-roll imprinting; spin coating and solution shearing are preferred.

[0017] In the spin coating method, the spin coating speed is 2000~5000 rad / min, and the spin coating time is 40~60 s, preferably 3000~5000 rad / min and 40~50 s; the spin coating solution used in the spin coating is preferably an L-SY-PPV polymer semiconductor solution with added polyacrylonitrile, the solvent is o-dichlorobenzene, and the concentration is 10 mg / mL~14 mg / mL; after spin coating, annealing treatment is required, and the annealing conditions are 10 min at 160℃.

[0018] The application of the above-mentioned stretchable electroluminescent polymer semiconductor thin film in the preparation of stretchable optoelectronic devices is also within the scope of protection of this invention.

[0019] The stretchable organic optoelectronic device may specifically be a hole-type single-carrier device or an intrinsically stretchable polymer light-emitting diode.

[0020] The present invention also provides a stretchable optoelectronic device having the above-mentioned doped thin film.

[0021] The stretchable optoelectronic device provided by the present invention includes the above-mentioned stretchable electroluminescent polymer semiconductor thin film.

[0022] The stretchable electroluminescent polymer semiconductor film is used as a light-emitting layer in the stretchable optoelectronic device.

[0023] The stretchable optoelectronic device can specifically be an intrinsically stretchable organic light-emitting diode (OLED). This stretchable OLED can be applied in the field of flexible displays.

[0024] The present invention also provides a solution-based method for fabricating intrinsically stretchable organic light-emitting diodes based on the above-mentioned doped thin films.

[0025] The solution-based intrinsically stretchable organic light-emitting diode fabrication method based on the above-mentioned doped thin film includes the following operations:

[0026] 1) Fabrication of patterned anode and cathode electrodes embedded in a stretchable substrate;

[0027] 2) A hole injection layer is prepared on the substrate containing the patterned anode prepared in step 1);

[0028] 3) Prepare a light-emitting layer on the hole injection layer prepared in step 2);

[0029] 4) Prepare an interface layer on the light-emitting layer prepared in step 3);

[0030] 5) Prepare an electron injection layer on the interface layer prepared in step 4);

[0031] 6) The cathode obtained in step 1) and the partial electrode prepared in step 5) are bonded together by heat transfer to obtain an intrinsically stretchable organic light-emitting diode device (device structure diagram is attached). Figure 1 (As shown).

[0032] In step 1) above, the intrinsically stretchable substrate may be a PDMS (Polydimethylsiloxane) substrate, a PUA (silicified polyurethane methacrylate), or a cross-linked SEBS (Styrene Ethylene Butylene Styrene) substrate.

[0033] The anode and cathode are selected from modified PEDOT:PSS with high conductivity, silver nanowires, and mixtures thereof.

[0034] The method for preparing the patterned electrode includes a spraying method and a two-step method of film formation and etching.

[0035] The patterned anode and cathode embedded in the stretchable substrate can be completed in three steps: first, a patterned electrode and a gel adhesion layer are prepared on a flat hard substrate (such as a silica substrate); then, a precursor solution of an elastomer is drop-coated onto the patterned electrode and the gel adhesion layer; the substrate is film-formed and the patterned electrode is embedded by heating (combined with light irradiation); finally, the patterned electrode embedded in the stretchable substrate is obtained by transfer.

[0036] The thickness of the patterned anode and cathode embedded in the stretchable substrate is 2~40 μm; wherein the thickness of the electrodes is 120~300 nm.

[0037] In step 2) above, the hole injection layer and transport layer can be an aqueous solution of PEDOT:PSS (poly(3,4-ethylenedioxythiophene-polystyrene sulfonate)) doped with Triton-X100 (polyethylene glycol octylphenyl ether), wherein the doping ratio of Triton-X100 is 5 wt%, and its work function is -5.0 to -5.2 eV, and its maximum elongation can reach 70%.

[0038] In step 3), the method for preparing the light-emitting layer can be spin coating, solution shearing film formation, or roll-to-roll imprinting; specifically, spin coating and solution shearing film formation are preferred.

[0039] In the spin coating method, the spin coating speed is generally 2000~5000 rad / min, and the spin coating time is generally 40~60 s, preferably 3000~5000 rad / min and 40~50 s; the spin coating solution used is preferably an L-SY-PPV polymer semiconductor solution with added PAN, the solvent can be o-dichlorobenzene, the spin coating speed can be 5000 rad / min, the spin coating time can be 50 min, and the annealing conditions after spin coating can be 10 min at 160℃; the thickness of the polymer semiconductor layer is 55~70 nm;

[0040] In step 4) above, the interface layer is an ultrathin PMMA, and the thickness of the interface layer can be 1 to 3 nanometers.

[0041] In step 5) above, the electron injection layer can be a bilayer structure composed of zinc oxide nanoparticles and PEIE / PFNBR (branched polyethyleneimine / poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-ALT-[(9,9-di-n-octylfluorenyl-2,7-diyl)bromo]).

[0042] In the electron injection layer, zinc oxide nanoparticles are prepared by spin coating. The zinc oxide nanoparticles are a 20-50 mg / mL ethanol solution. The spin coating speed can be 2000 rad / min, the spin coating time can be 50 min, and the thickness of the spin coating is generally 60-70 nm.

[0043] In the electron injection layer, PEIE / PFNBR is prepared using 2-methoxyethanol as a solvent at a concentration of 0.5 wt% by spin coating. The spin coating speed can be 4000 rad / min, the spin coating time can be 50 min, and the thickness of the spin coating is generally 15–20 nm.

[0044] This invention provides a doped structure for achieving high-performance stretchable electroluminescent polymer semiconductor films, thereby improving the mechanical properties of the luminescent polymer semiconductor while enhancing its electroluminescence performance, and applying it to the fabrication of stretchable optoelectronic devices. This invention uses luminescent polymer semiconductors with strong assembly capabilities as the base material. By doping with PAN, the assembly structure of the luminescent polymer is adjusted, and a low-scale three-dimensional through-cell nanonetwork structure is constructed, thus improving the mechanical properties of the luminescent polymer semiconductor film. The advantage of this structure is that the mechanical properties of the luminescent polymer film are improved without sacrificing its optoelectronic properties, thus enabling stretchable light-emitting devices with low driving voltage and high brightness. Furthermore, the application of this structure can further guide the design of current stretchable light-emitting materials, namely, improving the supramolecular assembly capabilities of luminescent polymers. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the intrinsically stretchable light-emitting diode designed in this invention; 1-Stretchable substrate / cathode, 2-Stretchable electron injection layer, 3-PMMA interface layer, 4-Stretchable light-emitting layer, 5-Stretchable hole injection layer, 6-Stretchable substrate / anode.

[0046] Figure 2 The images show a comparison of the tensile properties, surface morphology, and current-voltage characteristic curves of the L-SY-PPV polymer semiconductor thin film and the L-SY-PPV-doped PAN mixed film (7:3) prepared by spin coating in Example 1 and Comparative Example 1 of this invention.

[0047] Figure 3 The images show a comparison of the tensile properties, surface morphology, and current-voltage characteristic curves of the L-SY-PPV-doped PAN (5:5) polymer hybrid film and the L-SY-PPV-doped PDMS (5:5) hybrid film prepared in Example 2 and Comparative Example 2 of this invention.

[0048] Figure 4 The images show a comparison of the tensile properties, surface morphology, and current-voltage characteristic curves of the S-SY-PPV-doped PAN hybrid thin film (5:5) and the PHOPV-doped SEBS hybrid thin film (5:5) prepared in Example 3 and Comparative Example 3 of this invention. Detailed Implementation

[0049] The present invention will be described below through specific embodiments. The purpose of this invention is to provide a doped structure for realizing a high-performance stretchable electroluminescent polymer semiconductor thin film, thereby improving the mechanical properties of the luminescent polymer semiconductor and enhancing its electroluminescent performance, and applying it to the fabrication of stretchable optoelectronic devices. Therefore, the scope and materials of this invention are not limited to the contents of the following embodiments.

[0050] Unless otherwise specified, the experimental methods used in the following examples are all mature and commonly used methods; unless otherwise specified, the reagents, materials, instruments, etc. used in the following examples can be obtained commercially and used directly without special modification or optimization.

[0051] Because the selected materials are not sensitive to water and oxygen, the morphology and corresponding tensile properties of the polymer films prepared in this invention show no difference when tested in atmospheric and nitrogen atmospheres. Since the prepared devices involve a vapor deposition process, some steps are completed in a glove box, and then the electrical performance tests are performed in air.

[0052] Since polymer PAN exhibits good solubility only in N,N' dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), while commonly used polymer semiconductors are difficult to dissolve in both of these solvents, this invention uses o-dichlorobenzene as the solvent to balance these two types of materials. The solubility of PAN in o-dichlorobenzene is approximately 4 mg / mL.

[0053] The PAN solution was prepared as follows: 5 mg of PAN (molecular weight 150 kDa) was weighed, 1 mL of o-dichlorobenzene solvent was added, and then the solution was dissolved by sonication at 60 degrees Celsius for 1 hour. Then, the solution was dissolved by heating at 90 degrees Celsius for 12 hours. Finally, the solution was filtered through a 0.45 μm nylon 66 filter membrane to obtain a 4 mg / mL saturated PAN solution.

[0054] The preparation method of the mixed solution of luminescent polymer semiconductor doped with PAN is as follows: Based on a 4 mg / mL saturated PAN solution, weigh out the corresponding proportion of luminescent polymer semiconductor material, mix and stir evenly to obtain the mixed solution with the target ratio.

[0055] Example 1

[0056] This embodiment is based on a high molecular weight L-SY-PPV (molecular weight 420 kDa~1950 kDa, PDI=2.8) doped PAN (7:3, w / w) mixed solution to prepare a stretchable thin film and the corresponding hole-type single carrier device.

[0057] The preparation of stretchable films and the testing of their tensile properties were carried out using the following methods.

[0058] 1) Using a 1 cm × 1 cm piece of silicon dioxide cut by laser as a substrate, the substrate is soaked in piranha solution, then ultrasonically cleaned once with water, acetone and isopropanol in sequence, and then purged with high-purity nitrogen to remove the solvent from the substrate.

[0059] 2) The substrate obtained in step (1) is treated with an oxygen plasma treatment machine to make its surface have strong hydrophilicity; the specific conditions for oxygen plasma treatment are: power 30 W, oxygen pressure 10 mbr, time 10 minutes;

[0060] 3) An octadecyltrichlorosilane (OTS) modification layer was prepared on the substrate obtained in (2) using a vapor phase method. The vapor phase conditions for OTS modification were as follows: a small amount of OTS (about 1 fL) was coated onto the substrate after it was cleaned by oxygen plasma, and then it was placed in a vacuum oven with a vacuum degree of 0.01 Pa. The substrate was then heated to 120 °C and maintained for 3 h, and then allowed to cool naturally to room temperature to complete the modification process.

[0061] 4) A polymer semiconductor layer is prepared on the OTS-modified substrate of step (3) by spin coating.

[0062] The conditions for preparing the polymer semiconductor layer were as follows: the concentration of the L-SY-PPV-doped PAN mixed solution was 13.3 mg / mL (L-SY-PPV:PAN = 7:3, w / w), the solvent was o-dichlorobenzene, the spin coating speed was 4000 rad / min, and the spin coating time was 50 s. The prepared polymer semiconductor film was annealed at 160 ℃ for 10 min to obtain a polymer semiconductor layer with a thickness of 60 nm.

[0063] 5) The pre-prepared PDMS film is bonded to the polymer semiconductor film prepared in step (4), and then the polymer semiconductor film is transferred to the PDMS. The PDMS is stretched to the corresponding length using a self-made jig and then held in a stretched state.

[0064] 6) The PDMS-stretched film described in step (5) is bonded to the oxygen plasma-cleaned substrate prepared in step (2) to complete the preparation of the stretched film. Then, its stretching degree and corresponding surface morphology are tested using an optical microscope and an atomic force microscope.

[0065] The hole-type single-carrier device was fabricated using the following method.

[0066] The device structure of the hole-type single-carrier device is ITO (120 nm) / PEDOT:PSS (40 nm) / L-SY-PPV / PAN (7:3, w / w) (60 nm) / TAPC (40 nm) / MoO3 (5 nm) / Al (100 nm).

[0067] TAPC is 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline], and MoO3 is molybdenum oxide.

[0068] 1) Commercially available ITO glass substrate is used as the oxygen electrode. After being ultrasonically cleaned once in sequence with toluene, deionized water, acetone and isopropanol, the solvent on the substrate is removed by purging with high-purity nitrogen.

[0069] 2) The substrate obtained in step (1) is treated with an oxygen plasma treatment machine to make its surface have strong hydrophilicity; the specific conditions for oxygen plasma treatment are: power 30 W, oxygen pressure 10 mbr, time 10 minutes;

[0070] 3) A PEDOT:PSS hole injection layer is prepared on the plasma-cleaned ITO substrate obtained in step (2) by spin coating.

[0071] The PEDOT:PSS solution was model 4083. It was filtered through a 0.22-micron polyethersulfone filter membrane. The spin coating speed was 4000 rpm and the spin coating time was 40 s. After spin coating, the sample with the PEDOT:PSS film was transferred into a glove box under nitrogen atmosphere and annealed at 120 degrees Celsius for 30 minutes.

[0072] 4) Prepare a light-emitting layer on the hole injection layer obtained in step (3);

[0073] The conditions for preparing the polymer semiconductor layer were as follows: the concentration of the L-SY-PPV-doped PAN mixed solution was 13.3 mg / mL (L-SY-PPV:PAN = 7:3, w / w), the solvent was o-dichlorobenzene, the spin coating speed was 4000 rad / min, and the spin coating time was 50 s. The prepared polymer semiconductor film was annealed at 160 ℃ for 10 min to obtain a polymer semiconductor layer with a thickness of 60 nm.

[0074] 5) Transfer the sample obtained in step (4) into a vacuum evaporation system to prepare the remaining functional layer;

[0075] The pressure of vacuum evaporation is 1×10 -5 The evaporation rate of Pa and TAPC is 2 A / s, the evaporation rate of MoO3 is 0.3 A / s, and the evaporation rate of Al is 2 A / s.

[0076] The current-voltage characteristic curves of the fabricated single-carrier device were measured using a Keithley 2400 source meter (see...). Figure 3 ).

[0077] Comparative Example 1

[0078] The mixed polymer stretched film and the corresponding hole-type single carrier device were prepared using the same preparation method as in Example 1, except that the L-SY-PPV-doped PAN mixed polymer semiconductor solution was replaced with a pure L-SY-PPV solution with a concentration of 5 mg / mL and o-dichlorobenzene as the solvent.

[0079] The tensile properties of the polymer films in Comparative Example 1 and Comparative Example 1 were tested. Figure 2 ) and the corresponding current-voltage characteristics test results of hole-type single-carrier devices ( Figure 2 It can be seen that the introduction of PAN additives can effectively improve both the tensile properties and semiconductor properties of L-SY-PPV polymer films. Figure 2 The surface morphology comparison shows that PAN and L-SY-PPV blends form a low-scale nano-confined morphology.

[0080] Example 2

[0081] The hybrid polymer stretched film and the corresponding hole-type single-carrier device were prepared using the same method as in Example 1, except that the doping ratio of L-SY-PPV and PAN in the corresponding hybrid polymer semiconductor solution was changed to 5:5, the total concentration of the corresponding semiconductor solution was 8 mg / mL, and the spin-coating conditions of the corresponding light-emitting layer were changed to: spin-coating speed 2000 rpm, spin-coating time 40 s, while the other conditions remained unchanged.

[0082] Comparative Example 2

[0083] The hybrid polymer stretched film and the corresponding hole-type single-carrier device were prepared using the same method as in Example 2, except that the polymer PAN was replaced with PDMS (Sylgard). ® 184), with the rest of the conditions remaining unchanged.

[0084] The tensile properties of the polymer films in Example 2 and Comparative Example 2, and the current-voltage characteristics of the corresponding hole-type single-carrier devices were tested. Figure 3 As can be seen, the addition of PAN to form a low-scale nano-confined morphology is the key to ensuring that the hybrid film simultaneously achieves improved mechanical and semiconductor properties. After PDMS and L-SY-PPV are blended, a uniformly dispersed morphology is formed. Although the mechanical properties of the hybrid film are improved, its semiconductor properties decrease sharply, making it impossible to use this hybrid film to prepare the final stretchable light-emitting diode.

[0085] Example 3

[0086] The same preparation method as in Example 1 was used, except that the light-emitting polymer semiconductor was changed to a low molecular weight LY-PPV (labeled as S-LY-PPV, molecular weight 110 kDa~380 kDa, PDI=1.6), while all other conditions remained the same.

[0087] Comparative Example 3

[0088] The same preparation method as in Example 1 was used, except that the light-emitting polymer semiconductor was changed to PF-OPV (molecular weight 60 kDa~80 kDa, PDI=1.5) and the PAN polymer was changed to SEBS (model H1221, poly(ethylene-co-butene) ratio of 88%), while other conditions remained the same.

[0089] Based on the tensile property test results of the polymer films of Example 3 and Comparative Example 3, and the current-voltage characteristic test results of the corresponding hole-type single-carrier devices ( Figure 4 As can be seen, for luminescent polymer semiconductors with assembly characteristics, doping with PAN can form an effective low-scale nano-confined structure, thereby simultaneously improving the mechanical and semiconductor properties of the hybrid thin film.

Claims

1. A stretchable electroluminescent polymer semiconductor thin film, characterized in that: It is composed of a light-emitting polymer semiconductor doped with polyacrylonitrile or its copolymer with suitable assembly capabilities; The molecular weight of the light-emitting polymer semiconductor with suitable assembly capability is between 420 kDa and 1950 kDa; The film possesses a low-scale three-dimensional through-cell nanonetwork structure, which is uniformly distributed from top to bottom. Nanofibers and amorphous structures interpenetrate and stack to form an interpenetrating network structure. The nanofibers have a size between 20 nm and 50 nm. The light-emitting polymer semiconductor with suitable assembly capability is L-SY-PPV (poly[{2,5-di(3´,7´-dimethyloctoxy)-1,4-phenylacetylene}-co-{3-(4´-(3´´,7´´-dimethyloctoxy)phenyl)-1,4-phenylacetylene}-co-{3-(3´-(3´´,7´´-dimethyloctoxy)phenyl)-1,4-phenylacetylene}]); the mass ratio of L-SY-PPV to polyacrylonitrile or its copolymer is 0.4 to 3:

1.

2. The stretchable electroluminescent polymer semiconductor thin film according to claim 1, characterized in that: The molecular weight of the polyacrylonitrile PAN or its copolymer is 150 kDa.

3. The stretchable electroluminescent polymer semiconductor thin film according to claim 1 or 2, characterized in that: The thickness of the polymer semiconductor film is 55–70 nm.

4. A method for preparing a stretchable electroluminescent polymer semiconductor thin film according to any one of claims 1-3, comprising the following steps: preparing the polymer semiconductor thin film on an octadecyltrichlorosilane-modified substrate using a mixed solution of polyacrylonitrile or its copolymer with a luminescent polymer semiconductor having suitable assembly capabilities; The polymer semiconductor thin film can be prepared by spin coating, solution shearing, or roll-to-roll imprinting.

5. The preparation method according to claim 4, characterized in that: In the spin coating method, the spin coating speed is 2000~5000 rad / min, and the spin coating time is 40~60 s; the spin coating solution used is an L-SY-PPV polymer semiconductor solution with added polyacrylonitrile, the solvent is o-dichlorobenzene, and the concentration is 10 mg / mL~14 mg / mL; after spin coating, annealing treatment is performed, and the annealing conditions are 10 min and 160℃.

6. The preparation method according to claim 5, characterized in that: In the spin coating method, the spin coating speed is 3000~5000 rad / min and the spin coating time is 40~50 s.

7. The application of the stretchable electroluminescent polymer semiconductor thin film according to any one of claims 1-3 in the preparation of stretchable optoelectronic devices.

8. A stretchable optoelectronic device comprising the stretchable electroluminescent polymer semiconductor thin film according to any one of claims 1-3.

9. The stretchable optoelectronic device according to claim 8, characterized in that: The stretchable electroluminescent polymer semiconductor film is used as a light-emitting layer in the stretchable optoelectronic device; The stretchable optoelectronic device is an intrinsically stretchable organic light-emitting diode.

10. A method for fabricating an intrinsically stretchable organic light-emitting diode, comprising the following steps: 1) Fabrication of patterned anode and cathode electrodes embedded in a stretchable substrate; 2) A hole injection layer is prepared on the substrate containing the patterned anode prepared in step 1); 3) Prepare a light-emitting layer on the hole injection layer prepared in step 2); 4) Prepare an interface layer on the light-emitting layer prepared in step 3); 5) Prepare an electron injection layer on the interface layer prepared in step 4); 6) The cathode obtained in step 1) and the part prepared in step 5) are bonded together by heat transfer to obtain an intrinsically stretchable organic light-emitting diode device. Wherein, the light-emitting layer is a stretchable electroluminescent polymer semiconductor thin film according to any one of claims 1-3.

11. The preparation method according to claim 10, characterized in that: In step 1), the stretchable substrate is a PDMS substrate, a PUA substrate, or a cross-linked SEBS substrate; The anode and cathode are selected from modified PEDOT:PSS with high conductivity, silver nanowires, or a mixture of the two. The fabrication methods for the patterned anode and cathode include spraying or a two-step film-etching method. The thickness of the patterned anode and cathode embedded in the stretchable substrate is 2~40 μm; wherein the thickness of the anode and cathode is 120~300 nm. In step 2), the hole injection layer is a PEDOT:PSS aqueous solution doped with Triton-X100, and the doping ratio of Triton-X100 is 5 wt%. In step 3), the method for preparing the light-emitting layer is spin coating, solution shearing, or roll-to-roll imprinting. In the spin coating method, the spin coating speed is 2000-5000 rad / min, the spin coating time is 40-60 s, and the spin coating solution used is an L-SY-PPV polymer semiconductor solution with added polyacrylonitrile, the solvent is chlorobenzene, and the concentration is 10 mg / mL-14 mg / mL. After spin coating, annealing is performed at 160°C for 10 min. The thickness of the light-emitting layer is 55-70 nm. In step 4), the interface layer is an ultrathin PMMA layer with a thickness of 1–3 nm. In step 5), the electron injection layer is a bilayer structure composed of zinc oxide nanoparticles and PEIE / PFNBR (branched polyethyleneimine / poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-ALT-[(9,9-di-n-octylfluorenyl-2,7-diyl)bromo]). In the electron injection layer, zinc oxide nanoparticles are prepared by spin coating. The zinc oxide nanoparticles are a 20-50 mg / mL ethanol solution. The spin coating speed is 2000 rad / min, the spin coating time is 50 min, and the spin coating thickness is 60-70 nm. In the electron injection layer, PEIE / PFNBR is prepared using 2-methoxyethanol as solvent at a concentration of 0.5 wt% by spin coating at a speed of 4000 rad / min for 50 min, with a thickness of 15–20 nm.

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