An organometallic porphyrin polymer, a preparation method thereof and application thereof in a light detection device

Abstract

This invention belongs to the field of organic optoelectronics, and discloses an organometallic porphyrin polymer, its preparation method, and its application in organic semiconductor electronic devices, particularly organic semiconductor photodetectors. The general structural formula of the organometallic porphyrin polymer is shown below. The organic photodetector of this invention exhibits a low dark current, achieving a dark current of 1.5 × 10⁻⁶ at an operating voltage of -0.1V. ‑11 Acm ‑2 The dark current density. The response current responsivity at 800 nm is 0.4 AW. ‑1 The response current at 850 nm is 0.35 AW. ‑1 The device achieved a resolution exceeding 1.84 × 10⁻⁶. 14 Jones's specific detectivity and response time as low as 0.5 μs. This invention constructs an organic photodetector with low dark current, high specific detectivity, and fast response.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronics, and specifically relates to an organometallic porphyrin polymer, its preparation method, and its application in organic semiconductor electronic devices, particularly organic semiconductor photodetectors. Background Technology

[0002] Photodetectors play an indispensable role in real life, with wide applications in various civilian and military fields, such as imaging, night vision, optical communication, infrared remote sensing, process control, real-time monitoring, security, environmental monitoring, biomedicine, and spectroscopy. Compared to thermal detectors, photodetectors have higher detectivity. Currently, photodetectors based on semi-inorganic conductors such as silicon, germanium, and III-V compounds are relatively mature. However, photodetectors based on traditional inorganic semiconductor materials have a series of disadvantages, including high manufacturing costs, low spectral responsivity, poor compatibility with flexible substrates, and the inability to fabricate on a large scale, which cannot meet the needs of next-generation photodetectors.

[0003] Organic semiconductors possess advantages such as low fabrication cost, simple fabrication methods, large-area fabrication capability, good compatibility with flexible substrates, easily tunable absorption spectra, and high extinction coefficients. Organic semiconductor-based photodetectors play a crucial role in many emerging applications and hold promise for overcoming the shortcomings of inorganic semiconductor-based photodetectors. However, current organic semi-monomer photodetectors suffer from drawbacks such as low specific detectivity and long response time, limiting their development. Summary of the Invention

[0004] To address the shortcomings and deficiencies of existing technologies, the present invention aims to provide a class of organometallic porphyrin polymers that possess strong spectral absorption characteristics and a wide spectral absorption range. Furthermore, due to their large planar rigid structure, they can promote the planarity of the molecular backbone and the interaction between molecules, thereby improving the carrier mobility of organic semiconductors. This leads to the fabrication of an organic semiconductor photodetector with low dark current, high detectivity, and fast response.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned organometallic porphyrin polymer.

[0006] Another object of the present invention is to provide the application of the above-mentioned organometallic porphyrin polymer in organic semiconductor photodetectors.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] An organometallic porphyrin polymer has the following general structural formula:

[0009]

[0010] In the polymer structure, the multiple Rs can be the same or different, and each R independently represents one or more of the following: H atom, Cl atom, F atom, straight-chain alkyl with 1-60 C atoms, branched-chain alkyl with 1-60 C atoms, alkoxy with 1-60 C atoms, and alkylthiol with 1-60 C atoms; n is any natural number greater than 1; in the polymer structure, M represents one of the following metallic elements: Mn, Fe, Co, Ni, Cu, Zn, Pd, etc.; in the polymer structure, the multiple Xs can be the same or different, and each X independently represents one or more of the following elements: N, O, S, Se, etc.

[0011] The present invention also provides a method for preparing the above-mentioned organometallic porphyrin polymer, which includes the following steps:

[0012] Under nitrogen or inert gas protection, 5,15-di-ethynyl metalloporphyrin compounds and compound A are added to a solvent and refluxed in the presence of a catalyst. After the reaction is completed, the reaction is quenched, and then purified to obtain the metalloporphyrin polymer.

[0013] The reaction route for preparing the organometallic porphyrin polymer is shown below:

[0014]

[0015] The solvents mentioned include, but are not limited to, one or two of toluene, tetrahydrofuran (THF), triethylamine (Et3N), chloroform (CHCl3), xylene, chlorobenzene (CB), and dichlorobenzene (DCB).

[0016] The catalysts are tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) and cuprous iodide (CuI).

[0017] The reflux reaction time is 10–24 hours.

[0018] The quenching reaction mentioned refers to the reaction being quenched by adding a mixture of hydrochloric acid and methanol.

[0019] The purification process involves filtering the resulting reaction solution and then removing impurities, ions, and small oligomers from the polymer through one or more of the following methods: Soxhlet extraction, recrystallization, and dialysis. Preferably, the resulting reaction solution is filtered, and the resulting solid is then ground into powder and placed in a filter paper container for Soxhlet extraction, sequentially with acetone, petroleum ether, and chloroform. The chloroform extract is collected, concentrated, and then recrystallized and / or dialyzed 3-5 times to obtain a polymer with a molecular weight greater than 10. 3 Da's organometallic porphyrin polymers.

[0020] This invention also provides the application of metalloporphyrin-based polymers in the fabrication of organic semiconductor photodetectors, comprising the following steps:

[0021] (1) Fabrication of a conductive cathode on a substrate;

[0022] (2) An electron transport layer is prepared on a conductive cathode;

[0023] (3) Prepare an organic photoactive layer thin film on the electron transport layer;

[0024] (4) A MoO3 transport layer and an Ag anode are sequentially deposited on the organic photoactive layer.

[0025] The organic photoactive layer film described in step (3) is composed of the above-mentioned metalloporphyrin-based polymer and acceptor material.

[0026] Furthermore, the substrate mentioned in step (1) is at least one of glass, polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS) film, with a thickness of 0.5 to 1.5 mm.

[0027] Furthermore, the conductive cathode in step (1) is at least one of indium tin oxide (ITO) and fluorine tin oxide (FTO), with a thickness of 100–300 nm.

[0028] Furthermore, the electron transport layer in step (2) is ZnO with a thickness of 30-50 nm.

[0029] Further, in step (3), the organic photoactive layer is prepared by blending a metalloporphyrin polymer donor and a non-fullerene acceptor at a mass ratio of 1:(1-1.5) (preferably 1:1, 1:1.2, 1:1.5), dissolving in an organic solvent, and preparing a film by spin coating. The photoactive layer is then obtained by annealing to remove the organic solvent. The organic solvent is one of chloroform, chlorobenzene, toluene, o-xylene, and p-xylene.

[0030] In step (3), appropriate solvent additives can be added during the dissolution process to improve the solubility of the material and thus obtain a better film morphology. The solvent additives are at least one of 1,8-diiodooctane (DIO), 1,8-dibromooctane (DIO), pyrrole, and pyridine.

[0031] The non-fullerene receptor is selected from one of the following structures:

[0032]

[0033] In the non-fullerene acceptor structure, R can be the same or different. R can represent one or more of the following: H atom, straight-chain alkyl with 1-60 C atoms, branched-chain alkyl with 1-60 C atoms, and alkoxy with 1-60 C atoms.

[0034] The thickness of the MoO3 transport layer in step (4) is 5-50 nm; the thickness of the Ag anode is 80-180 nm.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) The organic photodetector described in this invention has a low dark current and achieves a dark current of 1.5 × 10⁻⁶ at an operating voltage of -0.1 V. -11 Acm -2 The dark current density. The response current responsivity at 800 nm is 0.4 AW. -1 The response current at 850 nm is 0.35 AW. -1 The device achieved a resolution exceeding 1.84 × 10⁻⁶. 14 Jones's specific detectivity and response time as low as 0.5 μs. This invention constructs an organic photodetector with low dark current, high specific detectivity, and fast response.

[0037] (2) The organic photodetector described in this invention has a higher detectivity and a shorter response time than similar detectors, and has great application prospects in future research and engineering applications. Attached Figure Description

[0038] Figure 1 The diagram shows the device structure of the organic photodetector in the embodiment.

[0039] Figure 2 H is the polymer P1 1 -NMR spectrum.

[0040] Figure 3 An atomic force microscope image of a blend of P1 polymer donor and L8-BO acceptor materials.

[0041] Figure 4 The image shows the dark current test results of the organic photodetector described in this invention.

[0042] Figure 5 The graph shows the EQE test results of the organic photodetector described in this invention.

[0043] Figure 6 This is a graph showing the specific detectivity test results of the organic photodetector described in this invention.

[0044] Figure 7This is a graph showing the responsivity test results of the organic photodetector described in this invention.

[0045] Figure 8 The graph shows the response time test results of the organic photodetector described in this invention.

[0046] Figure 9 This is the -3dB cutoff frequency of the organic photodetector described in this invention. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0048] Unless otherwise specified, all reagents used in the examples are commercially available.

[0049] Example 1

[0050] Preparation of metalloporphyrin-based polymers

[0051] (1) Preparation of 5-(2-ethylhexylthio)thiophene-2-carboxaldehyde

[0052]

[0053] First, under nitrogen protection, 1 g of thiophene (0.5 g, 6.0 mmol) was placed in a 250 mL two-necked flask and dissolved in 60 mL of THF. The solution was then transferred to a -78 °C cryostat and stirred for 15 min. Next, n-BuLi (1.6 M concin hex, 3.8 mL) was slowly added dropwise and stirred for 30 min. The solution was then transferred to an ice bath and 0.2 g of sulfur powder was added and stirred until the solution changed from turbid to clear. Then, 6.0 mmol of 1-bromo-2-ethylhexane was added and stirring continued for 2 h. The solution was then washed with water, extracted with n-hexane, and the organic solution was collected and concentrated. The crude product was separated by column chromatography, with n-hexane as the eluent, yielding 1.24 g of a colorless, transparent oily liquid, with a yield of 90%.

[0054] Then, under nitrogen protection, the obtained 2-(2-ethylhexylthio)thiophene (1.2 g, 4.4 mmol) was transferred into a 100 mL two-necked flask, and the flask was evacuated and filled with nitrogen three times. Next, N,N-dimethylformamide (DMF) (4.3 mL, 1 equiv.) and 1,2-dichloroethane (25 mL, 0.15 M conc.) were added, and the mixture was stirred until homogeneous. Then, POCl3 (4.1 mL, 1 equiv.) was slowly added dropwise under ice bath conditions, and the mixture was stirred for 1 h under a nitrogen atmosphere. Next, the reaction mixture was transferred to an oil bath, heated to 60 °C, and stirred overnight, with the reaction monitored using a thin-layer chromatography plate. After the reaction was complete, the mixture, now at room temperature, was poured into ice water and stirred. It was neutralized with NaHCO3 aqueous solution, extracted with n-hexane, dried over anhydrous MgSO4 to remove the solvent, and freeze-dried to obtain a yellow solid. No further purification was performed, and the reaction proceeded directly to the next step.

[0055] (2) Preparation of compound 1

[0056] First, dipyrrolemethane (DPM) (0.645 g, 4.4 mmol) and 5-(2-ethylhexylthio)thiophene-2-carboxaldehyde (1.87 g, 4.4 mmol) were placed in a 2 L reaction flask, and 1.5 L of DCM was added to dissolve them. The mixture was bubbled under nitrogen for 30 mins. Then, trifluoroacetic acid (TFA) (33.5 μL, 0.43 mmol) was added, and the mixture was stirred overnight under a nitrogen atmosphere and protected from light. Next, 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (1.51 g, 6.61 mmol) was added in one batch, and the reaction mixture was stirred for 1 h to 2 h. Then, triethylamine (NEt3) (5 mL) was added to quench the reaction. Finally, the solvent was evaporated, and the crude product was purified by silica gel chromatography to obtain 2.2 g of purple solid product, with a yield of approximately 65.5%.

[0057] (3) Preparation of compound 2

[0058] First, compound 1 (1.53 g, 2.0 mmol), NBS (0.75 g, 4.2 mmol), and pyridine (0.1 mL) were added to DCM (200 mL) and stirred at 0 °C for 30 mins. The reaction was monitored by TLC. After the reaction was complete, 5 mL of acetone was added and the solvent was removed under vacuum. Finally, the crude product was purified by silica gel chromatography to obtain 1.75 g of purple solid product, with a yield of approximately 95.1%.

[0059] (4) Preparation of compound 3

[0060] Compound 2 (1.38 g, 1.5 mmol) was dissolved in CHCl3 (200 mL); then, methanol (20 mL) containing zinc acetate (1.0 g, 4.5 mmol) was added, and the reaction was refluxed for 4 h, during which the solution changed from purple-red to green. After the reaction was completed by TLC monitoring, the crude product was purified by silica gel chromatography, yielding approximately 1.37 g of a solid product with a purple metallic luster, in approximately 90% yield.

[0061] (5) Preparation of compound 4

[0062] First, the product compound 3 (1.37 g, 1.35 mmol) from the previous reaction was added to a 100 mL two-necked reaction flask, along with CuI (11.7 mg, 0.1 eq), Pd(PPh3)4 (21.52 mg, 0.05 eq) and a stir bar. Then, a rubber stopper was attached to one end of the reaction flask, and a condenser and a double-row tube were attached to the other end. The reaction flask was then evacuated and filled with nitrogen (this process was repeated three times). Next, 15 mL of THF and 15 mL of NEt3 were added to the reaction flask sequentially, and the mixture was stirred until homogeneous. Next, 0.3 mL of trimethylsilylacetylene (TMSA) was slowly added dropwise to the reaction flask under ice bath conditions. The temperature inside the reaction vessel was slowly raised to 65 °C (reaction overnight), and the reaction was monitored in real time using MOLIT-TOF. After the starting materials had reacted completely, the reaction was stopped, and the system was allowed to return to room temperature. Then, the reaction solution was poured into 50 mL of water and extracted with DCM (30 mL × 3). The lower organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the solvent was evaporated. Finally, the crude product was passed through a column to obtain 945 mg of product, with a yield of approximately 70%.

[0063] (6) Preparation of compound 5 (5,15-di-ethynyl-10,20-di(5-ethylhexylthiophene[3,2-b]thiophene-2-yl)zinc porphyrin)

[0064] First, compound 4 (0.923 g, 0.88 mmol) was placed in a reaction flask and dissolved in 30 mL of THF. Then, under nitrogen protection, Bu4NF (1 M / THF, 7.5 mL) was slowly added dropwise to the reaction flask, and the mixture was stirred at room temperature for 1.5 h. Next, the solution was poured into 50 mL of water, extracted with DCM, and evaporated to dryness. Finally, the crude product was separated by column chromatography to obtain 477 mg of a yellow viscous liquid, with a yield of approximately 60%.

[0065] (7) Preparation of metalloporphyrin-based polymers (P1)

[0066] Weigh out pre-synthesized compound 5 and compound 1,3-bis[(5-bromo-4-(2-ethylhexyl)thiophen-2-yl]-5,7-bis(2-ethylhexyl)benzo[1,2-C:4,5-C']dithiophene-4,8-dione (BBDT). Under argon protection, weigh out equimolar amounts of compound 5 and BBDT and add them to a test tube. Add a small magnetic rotor, catalyst amounts of Pd(PPh3)4 and CuI, and add equal volumes of THF and Et3N through a syringe. Under liquid nitrogen protection, evacuate the tube, restore it to room temperature, and then purge it with argon. Repeat the process at least three times to ensure that the air in the reaction tube is completely replaced by argon. After the reaction tube has returned to room temperature, seal it and transfer it to an oil bath with stirring. Once the reactants have dissolved, slowly heat to reflux and observe the reaction progress (approximately 18 hours). When the reactants are mostly consumed, add hydrochloric acid / methanol to quench the reaction. Filter the resulting reaction solution, then grind the resulting solid into powder and place it in a filter paper container for Soxhlet extraction, sequentially using acetone, petroleum ether, and chloroform. Collect the chloroform extract, concentrate it, and dialyze it 3-5 times to obtain a molecular weight of 1.5 × 10⁻⁶. 4 The metalloporphyrin-based polymer of Da was dried in a vacuum drying oven.

[0067] The chemical reaction equations for synthesizing metalloporphyrin-based polymers are shown below:

[0068]

[0069] Example 2

[0070] Organic semiconductor photodetector fabrication

[0071] (1) Solution preparation: The metalloporphyrin-based polymer donor material and the non-fullerene acceptor material were blended at a mass ratio of 1:1.2 and dissolved in chloroform to a total concentration of 16 mg / ml. The mixture was heated and stirred at 50°C for 2 hours to obtain a homogeneous solution without precipitation. The molecular structure of the non-fullerene (L8-BO) acceptor material is shown below:

[0072]

[0073] (2) Cleaning of ITO glass substrate: The ITO glass substrate was ultrasonically cleaned in an ultrasonic bath for 10 minutes in acetone, ethanol, isopropanol, and deionized water and isopropanol in sequence to remove any dust, glass fragments, and grease that may have adhered to the surface. The cleaned ITO glass was then transferred to a room temperature forced-air oven and heated to 70°C for more than two hours. The dried ITO glass substrate was placed in a clean glass petri dish with the ITO side facing up and surface treated with a Plasma oxygen plasma cleaner for 2 minutes.

[0074] (3) Preparation of the ZnO thin film for the cathode transport layer: 2 g of zinc acetate was mixed with 550 μL of ethanolamine, 20 mL of ethylene glycol methyl ether, and 5 μL of 37% PEIE aqueous solution and heated at 60 °C for 9 hours to obtain a zinc oxide preparative solution. The solution was allowed to stand for 20-30 mins to return to room temperature. An appropriate amount of the solution was taken out using a syringe and filtered through a 0.45 μm polytetrafluoroethylene filter. The prepared solution was dropped onto a Plasma-treated ITO substrate and deposited onto the ITO surface using a spin coater at 3000 rpm to obtain a ZnO thin film with a thickness of approximately 45 nm.

[0075] (4) Place the ITO substrate with ZnO spin-coated on a hot plate and anneal at 150°C for 15 mins. Then transfer it to a nitrogen glove box and spin-coat the organic active layer after cooling.

[0076] (5) Spin-coating photoactive layer: The solution preparation is as described in (1) above. The photoactive layer preparation process is carried out in a glove box under nitrogen protection: a 200 nm thick bulk heterojunction layer is spin-coated on the ZnO layer with chloroform solution at a donor:acceptor ratio of 1:1.2 (wt:wt), and then thermally annealed at 100 °C for 10 mins.

[0077] (6) Electrode coating and vapor deposition: Remove the edge of the device coated with the active layer, exposing only a small strip of ITO. Then, place the device with the side without ZnO and organic functional layers facing up into the mask basket of the vapor deposition chamber. Evacuate the chamber and wait until the pressure inside the vapor deposition chamber is below 1×10⁻⁶. -4 After Pa, MoO3 / Ag electrodes were sequentially deposited via thermal evaporation. The MoO3 thickness was 20 nm, and the Ag thickness was 100 nm, resulting in an effective device area of ​​0.0516 cm². 2 .

[0078] (7) Device encapsulation: Apply an appropriate amount of epoxy resin to the device, cover it with a glass plate to encapsulate the device between two layers of glass to isolate water and oxygen, expose the electrode pins for testing, and finally cure with ultraviolet curing device for 2 minutes.

[0079] Figure 1 The device structure of this organic photodetector consists of, in sequence, a substrate material / ITO / ZnO / photoactive layer / MoO3 / Ag. The electron transport layer is ZnO, the MoO3 layer is 20 nm thick, and the active layer is a blend of metalloporphyrin-based polymer donor material and non-fullerene acceptor material, with a thickness of 200 nm.

[0080] Figure 2 H of P1 polymer 1 -NMR spectra indicate that the molecular structure of the material matches the target molecule.

[0081] Figure 3An atomic force microscope image of the blend film of P1 polymer donor material and L8-BO acceptor material shows that the root mean square roughness (RMS) of the surface morphology is 2.0 nm, indicating that the blend film has a relatively smooth surface.

[0082] Figure 4 This image shows the dark current test results of a bulk heterojunction organic photodetector with an active layer consisting of a P1 polymer donor material and a non-L8-BO acceptor material, as presented in this invention. At an operating voltage of -2.0V, this photodetector achieved a dark current of less than 10... -9 Acm -2 The dark current density.

[0083] Figure 5 The graph shows the EQE test results of the organic photodetector described in this invention. The external quantum efficiency in the range of 350nm-850nm all exceeds 50%, indicating that the above-mentioned active layer material has a very wide spectral response range.

[0084] Figure 6 The graph shows the test results of the specific detectivity of the organic photodetector described in this invention under different spectra.

[0085] Figure 7 The graph shows the test results of the responsivity of the organic photodetector described in this invention under different spectra.

[0086] Figure 8 The graph shows the response time test results of the organic photodetector described in this invention, with on and off response times of 0.5 μs and 2.0 μs, respectively.

[0087] Figure 9 This is the -3dB cutoff frequency of the organic photodetector described in this invention.

[0088] At an operating voltage of -0.1V, this photodetector achieved 10 -11 A cm -2 The dark current density. For incident light with a wavelength of 850 nm, the device achieves a specific detectivity of 10. 14 The spectral responsivity is above Jones level, the photodetector cutoff frequency is approximately 1.2 MHz, and the spectral responsivity is 0.35 A / W.

[0089] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the present invention should be included within the scope of the present invention.

Claims

1. An organic semiconductor photodetector, characterized by It is prepared by the following method: (1) Fabrication of a conductive cathode on a substrate; (2) An electron transport layer is prepared on a conductive cathode; (3) Prepare an organic photoactive layer thin film on the electron transport layer; (4) A MoO3 transport layer and an Ag anode are sequentially deposited on the organic photoactive layer; The organic photoactive layer film described in step (3) is composed of a metalloporphyrin-based polymer and a receptor material; The structure of the metalloporphyrin-based polymer is shown below: ； Where n is any natural number greater than 1.

2. The organic semiconductor photodetector according to claim 1, characterized in that: The preparation method of the organometallic porphyrin polymer includes the following steps: Under nitrogen or inert gas protection, 5,15-di-ethynyl metalloporphyrin compounds and compound A are added to a solvent and refluxed in the presence of a catalyst. After the reaction is completed, the reaction is quenched and then purified to obtain the metalloporphyrin polymer. The reaction route for preparing the organometallic porphyrin polymer is shown below: 。 3. The organic semiconductor photodetector according to claim 2, characterized in that: The solvent is one or two of toluene, tetrahydrofuran, triethylamine, chloroform, xylene, chlorobenzene, and dichlorobenzene; The catalyst is tetra(triphenylphosphine)palladium and cuprous iodide; The reflux reaction time is 10-24 hours; The purification process refers to filtering the obtained reaction solution and removing impurities, ions, and small molecule oligomers from the polymer through one or more of the following methods: Soxhlet extraction, recrystallization, and dialysis, to obtain polymers with a molecular weight greater than 10. 3 Da's organometallic porphyrin polymers.

4. The organic semiconductor photodetector according to claim 1, characterized in that: The substrate mentioned in step (1) is at least one of glass, polyvinyl alcohol, polyester, polyimide, polyethylene naphthalate, and polydimethylsiloxane film, with a thickness of 0.5 to 1.5 mm. The conductive cathode mentioned in step (1) is at least one of indium tin oxide (ITO) and fluorine tin oxide (FTO), and its thickness is 100–300 nm. The electron transport layer mentioned in step (2) is ZnO with a thickness of 30–50 nm; The thickness of the MoO3 transport layer in step (4) is 5~50nm; the thickness of the Ag anode is 80~180nm.

5. The organic semiconductor photodetector according to claim 1, characterized in that: The organic photoactive layer in step (3) is prepared by blending a metalloporphyrin polymer as described in claim 1 and a non-fullerene acceptor in a mass ratio of 1:(1-1.5), dissolving in an organic solvent, preparing a film by spin coating, and annealing to remove the organic solvent to obtain the photoactive layer.

6. The organic semiconductor photodetector according to claim 5, characterized in that: The non-fullerene receptor is selected from one of the following structures: ; In the non-fullerene acceptor structure, R may be the same or different, and each R independently represents one or more of the following: H atom, straight-chain alkyl with 1-60 C atoms, branched-chain alkyl with 1-60 C atoms, and alkoxy with 1-60 C atoms.

7. The organic semiconductor photodetector according to claim 5, characterized in that: The organic solvent is one of chloroform, chlorobenzene, toluene, o-xylene, and p-xylene; In step (3), an appropriate solvent additive is added during the dissolution process to improve the solubility of the material. The solvent additive is at least one of 1,8-diiodooctane, 1,8-dibromooctane, pyrrole, and pyridine.

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