An organic semiconductor soluble precursor containing a photo-cage group and a method for preparing a high performance organic semiconductor thin film thereof

Abstract

The application belongs to the technical field of organic semiconductors, and discloses an organic semiconductor soluble precursor containing a photo-cage group and a method for preparing a high-performance organic semiconductor thin film. The structural general formula of the organic semiconductor soluble precursor is G-L-P, G is a pi-conjugated skeleton, L is an active linking group, and P is a photo-cage group containing a solubilizing chain. The method comprises the following steps: dissolving the organic semiconductor soluble precursor containing the photo-cage group in an organic solvent, placing the organic semiconductor soluble precursor on a substrate to form a liquid film, and performing a photo-irradiation reaction to obtain an insoluble pi-conjugated thin film. Through photo-irradiation, the precursor triggers the removal of the solubilizing chain, so that the precursor molecules are converted into insoluble pi-conjugated materials, and a dense, continuous and solvent-resistant organic semiconductor thin film is formed on the substrate surface in situ. The method is simple, does not require high-temperature heat treatment or chemical post-treatment, is mild in process, and is compatible with various substrate materials. The obtained thin film has high conductivity after doping treatment.

Description

Technical Field

[0001] This invention belongs to the field of organic electronic materials technology, specifically relating to a soluble organic semiconductor precursor containing photocage groups and a method for preparing high-performance organic semiconductor thin films. Background Technology

[0002] π-conjugated organic semiconductor materials have been widely used in organic field-effect transistors (OFETs), organic photovoltaic devices (OPVs), and organic light-emitting diodes (OLEDs) due to their flexibility, lightweight, and solution-processability. However, high-performance, planar rigid π-conjugated molecules typically exhibit a strong tendency for intermolecular π-π stacking, resulting in poor solubility in conventional organic solvents. This limits their application in low-temperature solution processing, large-area continuous film deposition, and the fabrication of flexible electronic devices.

[0003] Current common strategies for improving the solubility of such molecules include introducing long-chain or branched alkyl substituents into the molecular structure, or weakening packing interactions by distorting molecular planarity. While these methods can improve the solubility of materials to some extent, they also disrupt the ordered packing structure between molecules, reduce carrier mobility, and thus weaken their charge transport performance. Furthermore, introducing bulky and insulating solubilizing chains may reduce the effective proportion of active components, dilute charge transport paths, and adversely affect the stable assembly and interface control of multilayer heterostructure devices.

[0004] To address the aforementioned contradictions, "soluble precursors" have been proposed and have gradually become an effective solution. This method involves introducing removable leaving groups into the target conjugated molecular structure to obtain precursor molecules with good solubility. A thin film is first prepared through solution processing, and then external stimuli such as heat treatment, light irradiation, or acid-base treatment are used to selectively remove the leaving groups, thereby achieving a structural transformation from the soluble precursor to the original π-conjugated framework. Ultimately, this yields an insoluble, dense, structurally ordered, and high-performance organic semiconductor thin film.

[0005] However, existing soluble precursor methods still have certain limitations. For example, some conversion mechanisms (such as retro-Diels-Alder reactions, decarbonylation aromatization reactions, etc.) usually depend on specific cyclic skeletons or functional group configurations, which severely limits the structural diversity and design freedom of molecules. At the same time, traditional removal processes usually need to be carried out under high temperature or strong acid and base conditions, which is not only energy-intensive, but also difficult to apply to device systems with flexible substrates, low-temperature processes, or sensitive functional layers.

[0006] Achieving precise activation of organic semiconductor precursor molecules in solution conditions, in-situ film formation in a non-abrasive environment at room temperature, and balancing spatial patterning capabilities with versatility in design remains a challenge, lacking mature and efficient technological solutions. Therefore, developing a photoresponsive precursor molecule suitable for various π-conjugated systems, possessing good chain-breaking efficiency and processing adaptability, combined with a simple, mild, and efficient photoinduced film formation and patterning method, is of great significance and has broad application prospects for promoting the low-cost, large-area fabrication of organic electronic devices. Summary of the Invention

[0007] To address the limitations of existing technologies, such as restricted reaction mechanisms of soluble precursors, stringent post-processing conditions, incompatibility with flexible low-temperature processes, and difficulty in achieving rapid solution-state patterning, this invention proposes a soluble organic semiconductor precursor containing photocage groups and a method for preparing high-performance organic semiconductor thin films. The soluble precursor of this invention enables solution processing, in-situ photo-controlled film deposition, and patterning under mild conditions, and possesses good versatility and device compatibility.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An organic semiconductor soluble precursor containing photocage groups has the general structural formula GLP, where G is a π-conjugated backbone, specifically one of the following structures: in the structure, * represents a connection site with L, and two * represent connection sites with two Ls.

[0010]

[0011] In the polyfluorene structure, one or more R1s are alkylene-L, and the other R1s are alkyl; R2 is alkyl; in the pyrrolopyrrole dione structure, R is H, alkyl or aryl (phenyl, naphthyl, etc.).

[0012] L represents an active linking group, specifically an ester group such as -C(O)-O-, -O-, or -O-(CH2). m -(m is an integer from 1 to 5), -CH2-C(O)-O-, -CH(R')-C(O)-O-, -NH-C(O)-, where R' is CH3, isopropyl, phenyl, or benzyl;

[0013] P is a photocage group, specifically one of the following structures: * in the structure indicates the connection site with L;

[0014]

[0015] R3 (solubilizer) is a straight-chain or branched alkyl, cycloalkyl, or -(O-CH2-CH2) chain. n -O-CH2-CH3, -CH2-CH2-(O-CH2-CH2)n -O-CH3, substituted alkyl, siloxane group; the substituted alkyl refers to a group in which the H on the alkyl group is replaced by a fluorine-substituted group or the C on the alkyl group is replaced by a carbonyl or ester group; the alkyl group in the straight-chain or branched alkyl group is C4-C 20 The alkyl group; wherein the substituted alkyl group is C4-C6. 20 Alkyl groups;

[0016] The structure of the cycloalkyl group is as follows: n≥1 integer; wavy lines represent connection points;

[0017] The structure of the siloxane group is as follows: The wavy line indicates the connection point.

[0018] The preferred option is G.

[0019] , , , .

[0020] L is preferably an ester group -C(O)-O-, -O-, -O-(CH2)2-, or -CH(R')-C(O)-O-, where R' is CH3, isopropyl, phenyl, or benzyl.

[0021] P is preferably... .

[0022] Preferably, the organic semiconductor soluble precursor containing photocage groups has one or more of the following structures;

[0023] .

[0024] The organic semiconductor soluble precursor containing photocage groups can be prepared by conventional methods.

[0025] The organic semiconductor soluble precursor containing photocage groups is used to prepare high-performance organic semiconductor thin films.

[0026] A method for preparing high-performance organic semiconductor thin films from an organic semiconductor soluble precursor containing photocage groups includes the following steps:

[0027] 1) A soluble organic semiconductor precursor containing photocage groups is dissolved in an organic solvent to obtain a precursor solution; the precursor solution is placed on a substrate to form a liquid film, and a photosensitive reaction is carried out to obtain an insoluble π-conjugated thin film. The organic solvent is a good solvent for the precursor.

[0028] The method further includes: 2) annealing and / or doping the insoluble π-conjugated thin film to obtain a high-performance organic semiconductor thin film.

[0029] The concentration of the precursor solution in step 1) is 1-50 mg / mL. -1 The organic solvent is one of dichloromethane, trichloromethane, tetrachloroethane, or aromatic hydrocarbons; the aromatic hydrocarbons include one or more of benzene, toluene, and xylene.

[0030] The substrate mentioned in step 1) is glass, silicon wafer, ITO, metal electrode or flexible substrate (PET, PI, etc.).

[0031] The conditions for the photoreaction are an irradiation intensity of 30-600 mW / cm² and an irradiation time of 10 seconds to 40 minutes.

[0032] The illumination refers to the use of ultraviolet or visible light, preferably with a wavelength of 300-450 nm. The illumination time is preferably 5-20 minutes.

[0033] The reaction is followed by cleaning. This cleaning refers to cleaning using a good solvent for the precursor.

[0034] The annealing process described in step 2) is either thermal annealing or solvent vapor annealing.

[0035] The conditions for heat annealing are as follows: temperature: 80 ~ 180℃, preferably 100 ~ 150℃; time: 5 ~ 60 minutes, preferably 10 ~ 30 minutes; atmosphere: carried out in a protective atmosphere (such as nitrogen or argon) or a vacuum environment.

[0036] The conditions for solvent vapor annealing are as follows: the film is placed in a sealed container and sealed together with a volatile organic solvent (preferably dichloromethane, trichloromethane, tetrahydrofuran, dichlorobenzene, etc.) to expose the film to a vapor environment. The treatment time is 2 to 60 minutes, preferably 5 to 30 minutes, and the temperature is room temperature to 60°C, preferably room temperature or below 40°C.

[0037] The doping treatment is immersion doping, vapor phase doping, or electrochemical doping.

[0038] The immersion doping refers to immersing the thin film in an organic solution containing a dopant.

[0039] The dopant is selected from one or more of F4TCNQ, F6TCNNQ, DDQ, iodine (I2), or hydrazine hydrate; the organic solvent is one or more of chloroform, dichloromethane, acetonitrile, and ethanol. The dopant concentration in the organic solution is 0.1 ~ 10 mg·mL. -1 The soaking time is 30 seconds to 30 minutes, preferably 1 to 10 minutes, and the operating temperature is room temperature.

[0040] The vapor phase doping refers to placing the thin film in a sealed container and exposing the film to the vapor environment of the dopant, preferably I2, F4TCNQ, NO2 or hydrazine hydrate, etc.

[0041] The gas phase doping conditions are performed at room temperature to 60°C for 10 to 600 seconds, preferably 60 to 300 seconds.

[0042] The electrochemical doping refers to using a thin film as the working electrode, constructing a standard three-electrode system, and applying a constant or scanning potential in the doped electrolyte solution. The doped electrolyte is LiClO4, Bu4NPF6, NaCl, etc., and the organic solvent in the electrolyte solution is one or more of acetone, acetonitrile, and THF.

[0043] The doping time is 10s to 10min.

[0044] A method for patterning organic semiconductor thin films based on photocage precursors includes the following steps:

[0045] A soluble precursor of an organic semiconductor containing photocage groups is dissolved in an organic solvent to obtain a precursor solution. The precursor solution is placed on a substrate to form a liquid film. The illumination area on the liquid film is controlled by a patterned mask, and then the film is illuminated. The illuminated area on the liquid film reacts to form an insoluble π-conjugated material. After the reaction is complete, the film is washed with an organic solvent to remove the unexposed area, thus obtaining a patterned organic semiconductor thin film.

[0046] The concentration of the precursor solution is 1-50 mg / mL. -1 Preferred dosage: 5-10 mg / mL -1 The organic solvent is one or more of dichloromethane, trichloromethane, tetrachloroethane, dimethylformamide, dichlorobenzene, benzene, toluene, and xylene.

[0047] To improve the performance of patterned organic semiconductor thin films, thermal treatment and / or doping treatment can be performed.

[0048] The thickness of the organic semiconductor thin film is 0.5-2.0 μm, preferably 0.8-1.2 μm, and the RMS surface roughness of the resulting thin film is better than 50 nm, preferably less than 30 nm.

[0049] The spatial resolution of the pattern structure is better than 200 μm, preferably better than 100 μm, and even more preferably better than 50 μm; the pattern is formed and patterned by single-step illumination, avoiding additional pattern transfer or etching processes.

[0050] Compared with the prior art, the present invention has the following advantages:

[0051] The present invention discloses an organic semiconductor soluble precursor containing photocage groups that is dissolved in an organic solvent and used to prepare organic semiconductor thin films through solution processing. In a continuous process of "photoinduced bond breaking-chain debonding-deposition", the precursor molecules are efficiently transformed into insoluble conjugated backbones under light irradiation and deposited. By controlling the irradiation area and dose, rapid patterning can be achieved on the basis of liquid precursors, without relying on traditional heat treatment, etching or development processes. The process is mild and easy to operate, and is particularly suitable for the low-temperature process requirements in flexible electronic devices.

[0052] This invention enables solution processing, in-situ photo-controlled film deposition, and patterning under mild conditions. The thin films of this invention are suitable for the low-cost fabrication of various organic field-effect transistors, organic photodetectors, flexible sensors, and other optoelectronic devices. Attached Figure Description

[0053] Figure 1 The synthesis route diagram for the photocage precursor PDI-oNB;

[0054] Figure 2 The synthesis route diagram for photocage precursor PDI-PTs;

[0055] Figure 3 The synthesis route diagram for the photocage precursor PDI-HBC;

[0056] Figure 4 The synthesis route diagram for the photocage precursor PDI-PF;

[0057] Figure 5 Synthesis route diagrams for photocage precursors PDI-1, PDI-3, and PDI-2;

[0058] Figure 6 NMR, FTIR, absorption, and emission spectra of PDI-1, PDI-3, and the precursor PDI-2; (a) 1H NMR spectrum; (b) FT-IR spectrum; (c) absorption spectra of dilute solutions and thin films; (d) emission spectra.

[0059] Figure 7 Characterization of PDI-1 precursors: (a) 1 (b) 1H NMR spectrum; (c) FT-IR spectrum; (d) absorption spectrum of dilute solution and thin film;

[0060] Figure 8 Representative thin film photographs, stereomicrographs, and AFM morphology images (5 μm × 5 μm): (ac) from 5 mg mL -1 PDI-1 precursor solution preparation; (df) from 5 mg mL -1PDI-1 precursor solution was prepared by washing with dichloromethane; (gi) was prepared from 5 mg mL -1 PDI-3 precursor solution preparation; (jl) from 10 mg mL -1 Preparation of PDI-3 precursor solution;

[0061] Figure 9 The curves showing the change in conductivity of the insoluble thin film obtained from PDI-1 with doping time are shown.

[0062] Figure 10 This is a schematic diagram of the patterning process in Example 7;

[0063] Figure 11 The absorption spectra of the thin films before illumination (solid line), after 40 minutes of illumination (dashed line), and after subsequent rinsing with dichloromethane (dotted line) are shown: (a) PDI-1, (b) PDI-2, and (c) PDI-3.

[0064] Figure 12 The contact angle images of the thin film are: (a) PDI-1, (b) PDI-2, (c) PDI-3;

[0065] Figure 13 (a) A schematic diagram of a traditional photolithography process based on photocage groups; (b) A typical experiment of photolithography preparation using the soluble precursor PDI-1; (c) An image of a PDI thin film prepared by photomask lithography.

[0066] Figure 14 Photolysis behavior of PDI-2: (a) reaction formula; (b) absorption spectrum; (c) emission spectrum; (d) 1 H NMR spectrum; (e) FT-IR characteristic changes. Detailed Implementation

[0067] The present invention will be further described below with reference to the embodiments and accompanying drawings, but the implementation and protection of the present invention are not limited to the following.

[0068] Synthesis of the photocage precursor PDI-oNB:

[0069] (1) Introduction of solubilizing group R (Williamson etherification): Starting with 5-hydroxy-2-nitrobenzaldehyde, in the presence of a base (such as K2CO3, NaH), it reacts with a brominated long-chain alkyl compound C. n H 2n+1 Br reacts in an anhydrous polar solvent (e.g., DMF) (under an argon atmosphere) to give an etherified product with long-chain substituents.

[0070] (2) Reduction to benzyl alcohol: Sodium borohydride (NaBH4) is used to selectively reduce the aldehyde group in the etherification product described in step (1) to a hydroxyl group in an alcohol or ether solvent (such as methanol) to obtain the o-nitrobenzyl alcohol intermediate;

[0071] (3) Constructing a carboxylic acid ester precursor: The above intermediate is esterified with different Boc-protected amino acids (such as N-Boc-glycine, N-Boc-2-aminopropionic acid, N-Boc-valine, N-Boc-2-phenylglycine, N-Boc-2-amino-3-phenylpropionic acid) in the presence of a condensing agent (such as EDC·HCl / DCC) and a catalyst (such as DMAP) to obtain Boc-protected oNB-amino acid esters;

[0072] (4) Removal of protecting group: The Boc-protected oNB-amino acid ester is deprotected under acidic conditions (such as TFA / dichloromethane) to obtain an amino derivative containing the oNB structure;

[0073] (5) Construction of PDI precursor: The amino derivative containing the oNB structure is reacted with 3,4,9,10-perylenetetracarboxylic acid dianhydride in a high-boiling solvent (e.g., imidazole) at 80~120℃ to introduce the oNB structure at the imide position of PDI to obtain the photoresponsive precursor PDI-oNB.

[0074] Structure of etherified products R2 is an alkyl C n H 2n+1 n is an integer from 4 to 20. Boc protects the amino acid structure: R1 is H, representing methyl, isopropyl, phenyl, or benzyl. The structure of amino derivatives containing the oNB structure: .

[0075] Structure of the photoresponsive precursor PDI-oNB: .

[0076] The synthesis route of the photocage precursor PDI-oNB is as follows: Figure 1 As shown.

[0077] The precursor of the present invention can also be formed by reacting a π-conjugated skeleton compound containing an active group with a PPG derivative, for example, the active functional group can be selected from hydroxyl, amino, carboxyl or phosphate groups, and then connecting them through esters, ethers, etc., to form a photolytically cleavable structure.

[0078] Photocage precursor PDI-PTs The preparation of R3 as C n H 2n+1 For example, its synthesis route diagram is as follows: Figure 2 As shown; photocage precursors PDI-HBC and PDI-PF The preparation of R3 as C n H 2n+1 For example, its synthesis route diagram is as follows: Figure 3 and 4 As shown.

[0079] Example 1

[0080] Synthesis of photocage precursors PDI-1, PDI-3, and PDI-2:

[0081] (1) Introduction of solubilizing group R (Williamson etherification): Using 5-hydroxy-2-nitrobenzaldehyde or 3-hydroxybenzaldehyde as starting material, in the presence of a base (such as K2CO3), it reacts with a brominated long-chain alkyl compound C. n H 2n+1 Br was reacted in an anhydrous polar solvent (e.g., DMF) at 60°C for 12 h (under an argon atmosphere) to give an etherified product with introduced long-chain substituents; the amount of 5-hydroxy-2-nitrobenzaldehyde or 3-hydroxybenzaldehyde was 1 equivalent, the amount of base was 3 equivalents, and the amount of the brominated long-chain alkyl compound was 1.5 equivalents; the brominated long-chain alkyl compound was C 12 H 25 Br or C 20 H 41 Br;

[0082] (2) Reduction to benzyl alcohol: Sodium borohydride (NaBH4) is used to selectively reduce the aldehyde group in the etherification product in step (1) to a hydroxyl group in methanol to obtain benzyl alcohol intermediate; 1 equivalent of the etherification product in step (1) and 1.5 equivalent of sodium borohydride are reacted at room temperature for 12 hours under an argon atmosphere.

[0083] (3) Constructing a carboxylic acid ester precursor: The above intermediate was esterified with N-Boc-glycine in the presence of a condensing agent (such as EDC·HCl / DCC) and a catalyst (such as DMAP) to obtain a Boc-protected amino acid ester; 0.9 equivalents of the intermediate obtained in step (2), 1 equivalent of N-Boc-glycine, 1.5 equivalents of condensing agent, and 0.5 equivalents of catalyst were reacted at room temperature under an argon atmosphere for 12 hours.

[0084] (4) Removal of protecting group: The Boc-protected amino acid ester is debonded under acidic conditions (such as HCl, 1,4-dioxane) to obtain an amino derivative; 1 equivalent of the product obtained in step (3) and 20 equivalents of HCl are stirred at 0 °C for 4 hours under an argon atmosphere.

[0085] (5) Construction of PDI precursors: The amino derivatives were reacted with 3,4,9,10-perylenetetracarboxylic acid dianhydride in a high-boiling solvent (e.g., imidazole) and zinc acetate at 80°C for 8 h to obtain photocage precursors PDI-1, PDI-3 and precursor PDI-2.

[0086] Structure of hydroxybenzaldehyde compounds When R1 is -NO2, the hydroxybenzaldehyde compound is 5-hydroxy-2-nitrobenzaldehyde; when R1 is H, the hydroxybenzaldehyde compound is 3-hydroxybenzaldehyde.

[0087] Etherification products: R2 is an alkyl C 12 H 25 Or C 20 H 41 .

[0088] The structure of the product in step (5):

[0089] ;

[0090] When R1 is -NO2, R2 is an alkyl C 12 H 25 At this point, the product is PDI-1;

[0091] When R1 is -NO2, R2 is an alkyl C 20 H 41 At this point, the product is PDI-3;

[0092] When R1 is H and R2 is an alkyl C 12 H 25 At this point, the product is PDI-2.

[0093] The synthesis route diagrams of photocage precursors PDI-1, PDI-3, and PDI-2 in this embodiment are as follows: Figure 5 As shown.

[0094] The NMR, FTIR, absorption, and emission spectra of the photocage precursors PDI-1, PDI-3, and PDI-2 in this embodiment are as follows: Figure 6 As shown, (a) 1H NMR spectrum; (b) FT-IR spectrum; (c) absorption spectrum of dilute solution and thin film; (d) emission spectrum.

[0095] Example 2: Photoreactivity Test

[0096] Using PDI-oNB precursor PDI-1 (R is a linear C) 12 Taking PDI-1 as an example, a photolysis experiment was conducted. PDI-1 was dissolved in dichloromethane to obtain a PDI-1 solution, which was then irradiated with ultraviolet light. The irradiation time (light intensity 600 mw / cm²) was adjusted.2 The changes of key peaks over time were analyzed by combining NMR, UV-Vis, PL and FT-IR spectroscopy. Figure 7 Characterization of the photolysis behavior of PDI-1: (a) reaction formula; (b) absorption spectrum; (c) emission spectrum; (d) 1 H NMR spectrum; (e) FT-IR.

[0097] like Figure 7 As shown in b, PDI-1 exhibited a significant reduction in its 313 nm absorption band after irradiation, consistent with the photolysis of the oNB group. Simultaneously, the intensity of the characteristic PDI absorption band gradually decreased, which can be attributed to reduced solubility after removal of the solubilizing side chains. Furthermore, the appearance of a new shoulder peak near 560 nm may be due to the aggregation of insoluble products generated during photolysis. The absorbance at 526 nm (λ...) max The degree of photoconversion (DPC) decreases with increasing irradiation time, thus allowing estimation of the extent of photoconversion. abs After 1200 seconds of irradiation, the light conversion rate of PDI-1 reached approximately 81%. Similarly, the trend shown in the in-situ emission spectrum was consistent with the absorption spectrum; the emission intensity of PDI-1 gradually decreased with increasing irradiation time. Figure 7 As shown in Figure c, the conversion efficiency (DPC) calculated based on the decrease in emission intensity after 1200 seconds of irradiation. em The NMR spectrum of PDI-1 reached approximately 85%. Figure 7 d) The bay and ortho regions of the perylene kernel (8.71–8.59 ppm) 1 The ¹H NMR signal gradually weakened and almost disappeared with increasing irradiation time, while the signal in the alkyl region remained essentially unchanged. This is due to the selective breaking of the oNB bond, leading to the removal of the solubilizing side chain and thus reducing solubility. Simultaneously, digital photographs of the NMR samples before and after irradiation showed a visible color change from orange transparent to dark red opaque, demonstrating the transition from a soluble state to an aggregated insoluble state. After 1200 seconds of irradiation, the photoreaction conversion rate, calculated from the integration of Bay and Ortho proton signals, reached 89%. Figure 7 As shown in e, 1511 and 1331 cm -1 The characteristic absorption peaks at 1745 and 1199 cm⁻¹, attributed to the nitro group, showed a significant decrease in intensity after illumination; meanwhile, the peaks at 1745 and 1199 cm⁻¹... -1 The absorption peaks related to the ester group in the vicinity also showed significant attenuation after light exposure.

[0098] Example 3: Photoinduced film formation

[0099] The precursor obtained in Example 1 was dissolved in dichloromethane, a good solvent, to prepare a solution with a concentration of 5-10 mg / mL. -1The solution was dropped onto a substrate (glass) surface that had undergone ultrasonic and plasma cleaning. It was then treated with 365 nm ultraviolet light (intensity 200 mW / cm²). -2 (20 min), followed by rinsing with a good solvent to remove unreacted precursors, yielding an insoluble π-conjugated film with a uniform surface, intact structure, and resistance to solvent rinsing (see...). Figure 8 ).

[0100] 5 mg mL -1 Thin films prepared from PDI-1 precursor solutions were cleaned before and after using a good solvent, and at 5 mg / mL. -1 PDI-3 and 10 mg mL -1 Unwashed film photographs, stereomicrographs, and AFM morphology images of PDI-3 prepared films are shown below. Figure 8 As shown. From Figure 8 As can be seen, the membrane obtained by irradiating the PDI-1 solution maintained good integrity before and after DCM rinsing. In contrast, the membrane prepared by PDI-3 showed slight aggregation under the same conditions. Increasing the concentration of the PDI-3 solution effectively compensated for this effect, resulting in a continuous and uniform PDI membrane.

[0101] Example 4: The effect of solvent selection on film quality

[0102] PDI-1 precursor solutions (concentration 1-2 mg / mL) were prepared using good solvents such as chloroform, dimethylformamide, and tetrachloroethane. -1 The solution was dropped onto the surface of a substrate (glass) that had undergone ultrasonic and plasma cleaning. It was then treated with 365 nm ultraviolet light (intensity 200 mW / cm²). -2 The photoreaction was carried out over a period of 20 min, followed by rinsing with a good solvent to remove unreacted precursors and form a film. The results showed that the photoreaction conversion rate could reach 80% (after 1200 seconds of light irradiation) under different solvent systems, and the RMS surface roughness of the obtained film was less than 40 nm (measured by AFM), with a denser and smoother film surface.

[0103] Tetrachloroethane is the most effective, with a roughness of 2 to 40 nm.

[0104] Example 6: Conductivity Test

[0105] The thin film obtained by irradiating the PDI-1 precursor solution (Example 2) was placed in a sealed container and exposed to hydrazine hydrate vapor under nitrogen protection for gas-phase doping (preferably at room temperature, exposure time ≤600 seconds). The conductivity test results of the doped film are as follows: Figure 9 As shown, the conductivity of the thin film prepared by light irradiation first increases with doping time and then tends to stabilize, reaching a maximum of 0.34 S·cm. -1 ( Figure 9).

[0106] Example 7: Patterning Experiment

[0107] A standard mask was placed under a glass substrate containing a precursor solution (PDI-1 precursor solution, with tetrachloroethane as the solvent, concentration 5 mg / mL). It was exposed to 365 nm UV light in stages at different times (60 seconds, 120 seconds, 240 seconds). Unexposed areas were then rinsed with dichloromethane to obtain a patterned film with progressively improved contrast. Figure 10 Pattern edge sharpness can be further optimized by adjusting the light dose, mask-substrate gap, and solution concentration.

[0108] Comparative Example 1: No light conditions

[0109] When a 5 mg / mL PDI-1 precursor solution was dropped onto a substrate (glass) that had been ultrasonically and plasma cleaned, and the substrate was not exposed to light, the film could not be formed or was easily dissolved by a good solvent when rinsed with dichloromethane. This indicates that photoinduction is a key step in converting the soluble precursor into a solvent-resistant film.

[0110] Comparative Example 2: Traditional film formation methods based on soluble precursor strategies

[0111] Precursor solutions of 5 mg / mL PDI-1, PDI-2, and PDI-3 (in chloroform) were solution-processed to form films, resulting in PDI-1, PDI-2, and PDI-3 films, respectively. The films were then irradiated with light and subsequently cleaned with dichloromethane.

[0112] The absorption spectra of PDI-1, PDI-2, and PDI-3 films before and after light exposure, and after dichloromethane cleaning, are as follows: Figure 11 As shown.

[0113] The contact angle test results of PDI-1 film, PDI-2 film, and PDI-3 film before and after light exposure and before and after dichloromethane cleaning are as follows: Figure 12 As shown. Before irradiation, the WCA of PDI-1, PDI-2, and PDI-3 films were 103°, 106°, and 104°, respectively. After DCM rinsing, the WCA of the unirradiated film decreased to 62-65°, indicating that the film was completely removed. In contrast, the contact angles of the irradiated and cleaned PDI-1 and PDI-3 films remained at around 94°, confirming that the formation of polar carboxylic acid groups after oNB photofragmentation increased surface hydrophilicity. PDI-2 showed no significant change, which is consistent with its lack of photocage groups.

[0114] This invention involves irradiating the precursor solution in a solution state, while this comparative example involves first forming a film and then irradiating it. In the solution state, due to the high interaction between the polymer and solvent, the molecular chains have high mobility, resulting in high photolysis efficiency. However, in solid films, molecular motion is restricted and the light penetration depth is limited, leading to a significant decrease in photolysis efficiency. Irradiating the film after formation inevitably causes problems such as film quality degradation and interface roughness, affecting the performance of the final device.

[0115] Comparative Example 3: Traditional Patterning Techniques

[0116] A 5 mg / mL PDI-1 precursor solution (chloroform as solvent) was spin-coated into a film. The PDI-1 precursor film was selectively exposed through a photomask under illumination to generate insoluble regions. The film was then rinsed with a solvent (dichloromethane) to obtain the insoluble pattern. Test results are as follows: Figure 13 As shown.

[0117] The method of the present invention involves irradiating the solution with light, which results in a faster reaction rate. Here, forming a film first and then irradiating it with light requires a longer irradiation time to display a clear pattern (more than 4 minutes).

[0118] Comparative Example 4: Study on photoreaction without optical cage connection

[0119] The PDI-2 precursor solution (with chloroform as the solvent) was exposed to light, and the test results are as follows. Figure 14 As shown, its spectra (NMR, UV-Vis, PL, and FT-IR) did not show significant changes, indicating the inherent photostability of the PDI framework. PDI-2 did not undergo photolysis.

[0120] Comparative Example 5: Film Formation Using a Non-Optical Cage Connecting Structure

[0121] The PDI-2 precursor solution (in chloroform) was placed on a substrate, irradiated, and then rinsed. No effective reaction occurred under irradiation, and a poorly soluble film could not be obtained after rinsing.

[0122] The above embodiments are preferred embodiments of the present invention and are intended to illustrate rather than limit the present invention. Those skilled in the art can substitute and optimize the raw material structure, connection method, type of photosensitive group, film formation parameters, and patterning process without departing from the core idea of ​​the present invention. All equivalent modifications that pertain to the substantive content of the present invention should be covered within the protection scope of the present invention.

Claims

1. A soluble organic semiconductor precursor containing a photocage group, characterized in that: Its general structural formula is GLP, where G is a π-conjugated skeleton, specifically one of the following structures: * in the structure represents the connection site with L. ； In the polyfluorene structure, one or more R1s are alkylene-L, and the other R1s are alkyl; R2 is alkyl; in the pyrrolopyrrole dione structure, R is H, alkyl or aryl; L represents an active linking group, specifically an ester group such as -C(O)-O-, -O-, or -O-(CH2). m -, m is an integer from 1 to 5, -CH2-C(O)-O-, -CH(R')-C(O)-O-, -NH-C(O)-, R' is CH3, isopropyl, phenyl, benzyl; P is a photocage group, specifically one of the following structures: * in the structure indicates the connection site with L; ； R3 is a straight-chain or branched alkyl, cycloalkyl, or -(O-CH2-CH2) group. n -O-CH2-CH3, -CH2-CH2-(O-CH2-CH2) n -O-CH3, substituted alkyl, siloxane group; the substituted alkyl refers to a group in which the H on the alkyl group is replaced by a fluorine-substituted group or the C on the alkyl group is replaced by a carbonyl or ester group; the alkyl group in the straight-chain or branched alkyl group is C4-C 20 The alkyl group; wherein the substituted alkyl group is C4-C6. 20 Alkyl groups; The structure of the cycloalkyl group is as follows: n≥1 integer; wavy lines represent connection points; The structure of the siloxane group is as follows: The wavy line indicates the connection point.

2. The organic semiconductor soluble precursor containing photocage groups according to claim 1, characterized in that: The G is 、 、 、 ； L represents an ester group -C(O)-O-, -O-, -O-(CH2)2-, or -CH(R')-C(O)-O-, and R' represents CH3, isopropyl, phenyl, or benzyl. P is .

3. The organic semiconductor soluble precursor containing photocage groups according to claim 1 or 2, characterized in that: Specifically, it is one or more of the following structures; 。 4. The application of the organic semiconductor soluble precursor containing photocage groups according to claim 1, characterized in that: The organic semiconductor soluble precursor containing photocage groups is used to prepare high-performance organic semiconductor thin films.

5. A method for preparing high-performance organic semiconductor thin films from organic semiconductor soluble precursors containing photocage groups, characterized in that: Includes the following steps: 1) Dissolve the soluble precursor of the organic semiconductor containing photocage group in an organic solvent to obtain a precursor solution; place the precursor solution on a substrate to form a liquid film, and react with light to obtain an insoluble π-conjugated thin film, i.e., an organic semiconductor thin film. The organic solvent is a good solvent for organic semiconductor soluble precursors; the organic semiconductor soluble precursor containing photocage groups is as defined in any one of claims 1 to 3.

6. The method for preparing high-performance organic semiconductor thin films from organic semiconductor soluble precursors containing photocage groups according to claim 5, characterized in that: The concentration of the precursor solution in step 1) is 1-50 mg / mL. -1 The organic solvent is one of dichloromethane, trichloromethane, tetrachloroethane, or aromatic hydrocarbons; the aromatic hydrocarbons include one or more of benzene, toluene, and xylene. The substrate mentioned in step 1) is glass, silicon wafer, ITO, metal electrode, or flexible substrate; The conditions for the photoreaction are: irradiation intensity of 30-600 mW / cm², and irradiation time of 10 seconds to 40 minutes; the photoreaction refers to the use of ultraviolet light or visible light. The light-induced reaction is followed by cleaning; the cleaning refers to cleaning using a good solvent for the precursor.

7. The method for preparing high-performance organic semiconductor thin films from organic semiconductor soluble precursors containing photocage groups according to claim 5, characterized in that: Also includes: 2) Annealing and / or doping of insoluble π-conjugated thin films to obtain high-performance organic semiconductor thin films.

8. The method for preparing high-performance organic semiconductor thin films from organic semiconductor soluble precursors containing photocage groups according to claim 7, characterized in that: The annealing process described in step 2) is either thermal annealing or solvent vapor annealing; The conditions for heat annealing are: temperature 80 ~ 180℃, time 5 ~ 60 minutes, and atmosphere conditions: carried out in a protective atmosphere or vacuum environment. The conditions for solvent vapor annealing are as follows: the film is placed in a sealed container and sealed together with the volatile organic solvent, so that the film is exposed to the vapor environment for 2 to 60 minutes at a temperature of room temperature to 60°C. The doping treatment is immersion doping, vapor phase doping, or electrochemical doping. The immersion doping refers to immersing the thin film in an organic solution containing a dopant; The dopant is selected from one or more of F4TCNQ, F6TCNNQ, DDQ, iodine, or hydrazine hydrate; the organic solvent is one or more of chloroform, dichloromethane, acetonitrile, or ethanol; the dopant concentration in the organic solution is 0.1 ~ 10 mg·mL. -1 The soaking time is 30 seconds to 30 minutes, and the operating temperature is room temperature. The vapor phase doping refers to placing the thin film in a sealed container and exposing the film to the vapor environment of the dopant, such as I2, F4TCNQ, NO2, or hydrazine hydrate. Conditions for vapor-phase doping: treatment at room temperature to 60°C for 10 to 600 seconds; The electrochemical doping refers to using a thin film as the working electrode, constructing a standard three-electrode system, and applying a constant potential or scanning potential in the doped electrolyte solution; the doped electrolyte is LiClO4, Bu4NPF6, NaCl, etc., and the organic solvent in the electrolyte solution is one or more of acetone, acetonitrile, and THF; the doping time is 10s~10min.

9. A method for patterning organic semiconductor thin films based on organic semiconductor soluble precursors containing photocage groups, characterized in that: Includes the following steps: An organic semiconductor soluble precursor containing photocage groups is dissolved in an organic solvent to obtain a precursor solution. The precursor solution is placed on the substrate to form a liquid film. The light-illuminated area on the liquid film is controlled by a patterned mask. Then, light is irradiated, and the light-illuminated area on the liquid film reacts to form an insoluble π-conjugated material. After the reaction is complete, the unexposed area is removed by rinsing with an organic solvent to obtain a patterned organic semiconductor thin film. The organic semiconductor soluble precursor containing photocage groups is as defined in any one of claims 1 to 3; The concentration of the precursor solution is 1-50 mg / mL. -1 The organic solvent is one or more of dichloromethane, trichloromethane, tetrachloroethane, dimethylformamide, dichlorobenzene, benzene, toluene, and xylene. To improve the performance of patterned organic semiconductor thin films, or to perform thermal treatment and / or doping treatment on patterned organic semiconductor thin films.

10. An application of a high-performance organic semiconductor thin film obtained by the method of any one of claims 5 to 8 or a patterned organic semiconductor thin film obtained by the method of claim 9, characterized in that: The organic semiconductor thin film is applied to at least one of organic field-effect transistors, organic photodetectors, organic photovoltaic devices, organic thermoelectric devices, or flexible electronic devices.

Images