A molecular film phototransistor and its preparation method

Abstract

The present invention relates to the technical field of transistor preparation, and provides a molecular film phototransistor and a preparation method thereof, the method comprising: spin coating a photoresist on a substrate, sequentially performing an exposure process and an evaporation process on the substrate to obtain a first intermediate containing a metal electrode; self-assembling a photosensitive molecular film on the first intermediate to obtain a second intermediate; preparing a third intermediate with a single-layer graphene grown thereon; preparing a fourth intermediate containing a graphene strip; preparing a fifth intermediate containing a graphene metal electrode; spin coating polymethyl methacrylate on the fifth intermediate, immersing it in a ferric chloride hydrochloric acid solution, etching and removing the copper foil, washing, and obtaining a sixth intermediate; placing the sixth intermediate on the second intermediate to obtain a molecular film phototransistor. The present invention realizes rapid preparation of a molecular film phototransistor with low cost, high environmental stability, simple preparation process, and high yield.

Description

Technical Field

[0001] The present invention relates to the technical field of transistor preparation, and in particular to a molecular film phototransistor and a preparation method thereof. Background Art

[0002] Transistor devices are the core components of modern electronic technology and are widely used in various electronic devices in daily life. These devices have evolved from early silicon and germanium transistors to modern metal oxide semiconductor field effect transistors and integrated circuits, with continuous improvement in performance, gradual reduction in size, continuous reduction in power consumption, and significant increase in integration, laying a solid foundation for the advancement of modern electronic technology.

[0003] Phototransistors combine the characteristics of optoelectronics and electronic devices, can respond to optical and electrical signals at the same time, and have broad application prospects in display technology, photodetection, optical communications, and optical computing. However, as transistors develop and gradually approach the limits of Moore's Law, phototransistors face many challenges and bottlenecks, including size limitations, response sensitivity, integration and compatibility, manufacturing costs, process complexity, environmental stability, and recyclability.

[0004] Researching and developing new phototransistor devices has become an important way to solve the performance bottleneck of transistor devices. Among them, molecular film phototransistors are micro-nanoscale devices constructed using molecular layers or single-layer films. They have unique physical, chemical and mechanical properties and are usually used in electronics, optoelectronics, sensors and other fields. Molecular film phototransistors can be designed according to different application scenarios and functional needs, and have the advantages of small size, low power consumption, fast response speed and high sensitivity.

[0005] However, molecular film phototransistors also have the problem of poor molecular film stability and susceptibility to environmental factors such as chemicals, heat and light. The reliability of device operation may be affected by ambient temperature and humidity conditions. At the same time, the preparation process is more complicated than that of silicon-based phototransistors. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a molecular film phototransistor and a preparation method thereof, which realizes a molecular film phototransistor with low rapid preparation cost, high environmental stability, simple preparation process and high yield.

[0007] The present invention provides a method for preparing a molecular film phototransistor, comprising the following steps:

[0008] S100, spin coating a photoresist on a substrate, and sequentially performing an exposure process and an evaporation process on the substrate to obtain a first intermediate including a metal electrode;

[0009] S200, self-assembling a photosensitive molecular film on the first intermediate to obtain a second intermediate;

[0010] S300, pre-treating the copper foil by immersing it in acetic acid, rinsing the pre-treated copper foil with ultrapure water and ethanol, and placing the rinsed copper foil in a chemical vapor deposition tube furnace to obtain a third intermediate having a single-layer graphene grown thereon;

[0011] S400, pressing a first metal mask on the third intermediate, and performing etching in a plasma gas environment to obtain a fourth intermediate including graphene strips;

[0012] S500, pressing a second metal mask on the fourth intermediate, and evaporating metal to obtain a fifth intermediate including a graphene metal electrode;

[0013] S600, spin-coating polymethyl methacrylate on the fifth intermediate, immersing in a ferric chloride hydrochloric acid solution, etching to remove the copper foil, and washing to obtain a sixth intermediate;

[0014] S700, placing the sixth intermediate on the second intermediate to obtain a molecular film phototransistor.

[0015] According to a method for preparing a molecular film phototransistor provided by the present invention, the substrate comprises one of a silicon wafer, boron nitride or mica.

[0016] According to a method for preparing a molecular film phototransistor provided by the present invention, in the step S100, the roughness of the upper surface of the first intermediate is less than or equal to 1 nm.

[0017] According to a method for preparing a molecular film phototransistor provided by the present invention, in step S200, the terminal connecting group of the photosensitive molecule of the photosensitive molecular film includes one of mercapto, sulfonic acid, pyrene or thiomethyl.

[0018] According to a method for preparing a molecular film phototransistor provided by the present invention, in step S200, the molecular formula of the photosensitive molecule of the photosensitive molecular film is:

[0019] .

[0020] According to a method for preparing a molecular film phototransistor provided by the present invention, the preparation process of the photosensitive molecule is as follows:

[0021] In a nitrogen environment, dibromodinitrobenzothiazole, iron powder and acetic acid are mixed and stirred at room temperature for 8 hours to 14 hours to obtain a first reaction solution;

[0022] The first reaction solution was evaporated to remove the solvent, and then separated by column chromatography to obtain ;

[0023] In a nitrogen environment, and oxalyl chloride were dissolved in dimethylformamide, and then hydrochloric acid was added, refluxed for 8 to 12 hours, and separated by rotary evaporation to obtain ;

[0024] In a nitrogen environment, , 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)benzenethiol and tetrakis(triphenylphosphine)palladium are dissolved in a mixed solvent of ethylene glycol dimethyl ether and water, reacted at a temperature of 80° C. to 90° C. for 7 to 9 hours, cooled to room temperature, and the solvent is removed under pressure to obtain a second reaction solution;

[0025] The second reaction solution was added to water and dichloromethane for extraction, and then anhydrous sodium sulfate was added for drying. The solvent was removed by rotary evaporation and separated by column chromatography to obtain ;

[0026] Will Dissolve in dichloromethane solvent, add N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, and then add , obtaining a third reaction solution;

[0027] The third reaction solution is purified and filtered to obtain a photosensitive molecule.

[0028] According to a method for preparing a molecular film phototransistor provided by the present invention, the plasma gas is argon.

[0029] According to a method for preparing a molecular film phototransistor provided by the present invention, in step S500, the material of the graphene metal electrode includes one of gold, silver or platinum.

[0030] According to a method for preparing a molecular film phototransistor provided by the present invention, the step S600 further includes:

[0031] S610, using oxygen plasma gas to etch the back side of the fifth intermediate after spin coating of polymethyl methacrylate, to remove graphene on the back side of the fifth intermediate.

[0032] The present invention also provides a molecular film phototransistor, which is prepared based on the molecular film phototransistor preparation method as described in any one of the above items, comprising:

[0033] The substrate, metal electrode, photosensitive molecular film, graphene electrode and polymethyl methacrylate layer are arranged in sequence from bottom to top.

[0034] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0035] 1. By introducing the metal mask technology and using the copper foil for growing graphene as the substrate for preparing the electrode, there is no need to replace the substrate when preparing the graphene electrode. The metal mask technology can effectively simplify the preparation process of the molecular film phototransistor, and quickly prepare graphene electrodes in batches, so that the overall molecular film phototransistor has the advantages of low preparation cost, short cycle and high success rate;

[0036] 2. By introducing a metal hollow mask to prepare graphene strips and graphene electrodes, no photoresist is used in this process, which can completely avoid the subsequent photoresist residue and the damage to graphene during the removal process, so that there is a clean and tidy contact interface between graphene and the metal electrode, which can further improve the performance of molecular film phototransistors;

[0037] 3. By using centimeter-sized transferred graphene strips as electrodes of molecular film phototransistors, multiple molecular film phototransistor array devices can be prepared simultaneously, achieving large-scale and low-cost production and integration;

[0038] 4. By transferring the graphene strips and the electrode-coated polymethyl methacrylate, which is subsequently covered on the upper surface of the molecular film, it can not only serve as a supporting layer for the graphene strips, but also has good optical transparency and corrosion resistance. The dense polymethyl methacrylate film can effectively isolate air and water, thereby significantly improving the life and performance stability of the molecular film phototransistor.

[0039] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 It is a schematic flow chart of the method for preparing the molecular film phototransistor provided by the present invention.

[0042] Figure 2 It is a schematic diagram of the first metal mask in the method for preparing the molecular film phototransistor provided by the present invention.

[0043] Figure 3 It is a schematic diagram of the second metal mask in the method for preparing the molecular film phototransistor provided by the present invention.

[0044] Figure 4It is a schematic structural diagram of the molecular film phototransistor provided by the present invention.

[0045] Figure 5 It is an I / V curve diagram of the molecular film phototransistor test provided by the present invention.

[0046] Figure 6 It is an I / T curve diagram of the light test of the molecular film phototransistor provided by the present invention.

[0047] Reference numerals:

[0048] 1. Substrate; 2. Metal electrode; 3. Photosensitive molecular film; 4. Graphene electrode; 5. Polymethyl methacrylate layer. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0050] In the description of the embodiments of the present invention, it should be noted that the terms “first”, “second” and “third” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0051] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0052] Combine the following Figures 1 to 6 The present invention describes a molecular film phototransistor and a method for preparing the same.

[0053] The present invention provides a method for preparing a molecular film phototransistor, comprising the following steps:

[0054] S100, spin coating a photoresist on a substrate, and sequentially performing an exposure process and an evaporation process on the substrate to obtain a first intermediate including a metal electrode;

[0055] S200, self-assembling a photosensitive molecular film on the first intermediate to obtain a second intermediate;

[0056] S300, pre-treating the copper foil by immersing it in acetic acid, rinsing the pre-treated copper foil with ultrapure water and ethanol, and placing the rinsed copper foil in a chemical vapor deposition tube furnace to obtain a third intermediate having a single-layer graphene grown thereon;

[0057] S400, pressing a first metal mask on the third intermediate, and performing etching in a plasma gas environment to obtain a fourth intermediate including graphene strips;

[0058] S500, pressing a second metal mask on the fourth intermediate, and evaporating metal to obtain a fifth intermediate including a graphene metal electrode;

[0059] S600, spin-coating polymethyl methacrylate on the fifth intermediate, immersing in a ferric chloride hydrochloric acid solution, etching to remove the copper foil, and washing to obtain a sixth intermediate;

[0060] S700, placing the sixth intermediate on the second intermediate to obtain a molecular film phototransistor.

[0061] According to a method for preparing a molecular film phototransistor provided by the present invention, the substrate comprises one of a silicon wafer, boron nitride or mica.

[0062] According to a method for preparing a molecular film phototransistor provided by the present invention, in the step S100, the roughness of the upper surface of the first intermediate is less than or equal to 1 nm.

[0063] According to a method for preparing a molecular film phototransistor provided by the present invention, in step S200, the terminal connecting group of the photosensitive molecule of the photosensitive molecular film includes one of mercapto, sulfonic acid, pyrene or thiomethyl.

[0064] According to a method for preparing a molecular film phototransistor provided by the present invention, in step S200, the molecular formula of the photosensitive molecule of the photosensitive molecular film is:

[0065] .

[0066] According to a method for preparing a molecular film phototransistor provided by the present invention, the preparation process of the photosensitive molecule is as follows:

[0067] In a nitrogen environment, dibromodinitrobenzothiazole, iron powder and acetic acid are mixed and stirred at room temperature for 8 hours to 14 hours to obtain a first reaction solution;

[0068] The first reaction solution was evaporated to remove the solvent, and then separated by column chromatography to obtain ;

[0069] In a nitrogen environment, and oxalyl chloride were dissolved in dimethylformamide, and then hydrochloric acid was added, refluxed for 8 to 12 hours, and separated by rotary evaporation to obtain ;

[0070] In a nitrogen environment, , 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)benzenethiol and tetrakis(triphenylphosphine)palladium are dissolved in a mixed solvent of ethylene glycol dimethyl ether and water, reacted at a temperature of 80° C. to 90° C. for 7 to 9 hours, cooled to room temperature, and the solvent is removed under pressure to obtain a second reaction solution;

[0071] The second reaction solution was added to water and dichloromethane for extraction, and then anhydrous sodium sulfate was added for drying. The solvent was removed by rotary evaporation and separated by column chromatography to obtain ;

[0072] Will Dissolve in dichloromethane solvent, add N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, and then add , obtaining a third reaction solution;

[0073] The third reaction solution is purified and filtered to obtain a photosensitive molecule.

[0074] According to a method for preparing a molecular film phototransistor provided by the present invention, the plasma gas is argon.

[0075] According to a method for preparing a molecular film phototransistor provided by the present invention, in step S500, the material of the graphene metal electrode includes one of gold, silver or platinum.

[0076] According to a method for preparing a molecular film phototransistor provided by the present invention, the step S600 further includes:

[0077] S610, using oxygen plasma gas to etch the back side of the fifth intermediate after spin coating of polymethyl methacrylate, to remove graphene on the back side of the fifth intermediate.

[0078] In a specific embodiment of the present invention, a method for preparing a molecular film phototransistor comprises the following steps:

[0079] S100, spin-coating photoresist on the substrate, exposing and developing it with a UV exposure machine, and then vapor-depositing it in a thermal resistance evaporation coating apparatus to obtain a first intermediate including a metal electrode, wherein the metal electrode serves as a bottom electrode.

[0080] In this embodiment, the substrate is a silicon wafer (including a back gate), wherein the surface silicon oxide of the silicon wafer is used as an insulating dielectric layer, and silicon is used as a back gate. The material of the metal electrode is silver.

[0081] S200, self-assemble a molecular film on the first intermediate (substrate containing the bottom electrode), immerse the bottom electrode in an in-situ deprotected molecular film solution in a dark environment, assemble the molecular film in a nitrogen environment overnight to obtain a second intermediate, and then thoroughly rinse the second intermediate with acetone, methanol and dichloromethane;

[0082] Among them, the molecular formula of the photosensitive molecule of the photosensitive molecular film is:

[0083] ;

[0084] The preparation process of the photosensitive molecule is as follows:

[0085] Under nitrogen protection, dibromodinitrobenzothiazole (1.18 g, 3.1 mmol), iron powder (0.10 g, 1.7 mmol), and acetic acid (20 mL) were added to a 50 mL two-necked bottle in sequence, and the mixture was stirred at room temperature for 12 hours to obtain a first reaction solution;

[0086] The first reaction solution was evaporated to remove the solvent, and then separated by column chromatography to obtain ;

[0087] Subsequently, under nitrogen protection, add (1.14 g, 3.00 mmol) and oxalyl chloride (0.38 g, 3.00 mmol) were dissolved in 10 ml of dimethylformamide (DMF), 5 ml of hydrochloric acid was added, refluxed for 10 hours, and separated by rotary evaporation to obtain ;

[0088] Under nitrogen protection, add the following into a 50 mL two-necked bottle: (0.376 g, 1.00 mmol), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborol-2-yl)benzenethiol (0.472 g, 2.00 mmol), tetrakis(triphenylphosphine)palladium (0.046 g, 0.04 mmol), and then add 20 mL of a mixed solvent of ethylene glycol dimethyl ether and water (volume ratio of 4:1), and the mixture is reacted at 85°C for 8 h. After the reaction is completed, it is cooled to room temperature, and the solvent is removed under reduced pressure to obtain a second reaction solution;

[0089] Water (10 mL) was added to the second reaction solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and then the solvent was removed by rotary evaporation. Column chromatography was used to separate the obtained ;

[0090] Dissolve in dry dichloromethane solvent (1.00mmol), slowly add the activator N,N'-dicyclohexylcarbodiimide and the auxiliary agent 4-dimethylaminopyridine to activate the pyrene unit, and then add an equal amount of (1.00mmol), the sulfur atom of the thiol group acts as a strong nucleophilic agent and attacks the carbonyl carbon atom of the active ester. The sulfur atom and the carbonyl carbon atom form a new bond. After the reaction is completed, the third reaction solution is obtained. The photosensitive molecule is obtained by purifying and filtering the third reaction solution. .

[0091] Among them, the above-mentioned photosensitive molecules have the following advantages:

[0092] (1) The molecular end anchoring groups are designed as thiol and pyrene groups. The thiol group is converted into a thiol ion by losing hydrogen atoms, which can form a strong covalent bond with the metal surface, which is conducive to the stable construction of a dense molecular film. The pyrene group electrode can enhance the non-covalent interaction between the molecular film and the graphene electrode, such as Figure 5 As shown, stronger interface coupling can expand the charge transfer channel of the molecular film phototransistor, thereby increasing the conductivity and improving the photoelectric performance of the device.

[0093] (2) The core groups of the photosensitive molecules are thiadiazole and quinoxaline. Thiadiazole can absorb ultraviolet light to produce an excited state. Light can cause charge separation and transfer. Quinoxaline can absorb ultraviolet and visible light and has good photostability, which enables it to maintain excellent photosensitivity under long-term light irradiation and increase the life of the molecular film phototransistor. Figure 6 As shown, the molecular film phototransistor can still maintain a fast light response after multiple light cycle tests.

[0094] S300, pre-treating the copper foil by soaking it in acetic acid, and then repeatedly rinsing it with ultrapure water and ethanol. The cleaned copper foil is placed in a chemical vapor deposition (CVD) tube furnace, and a single layer of graphene is grown on the surface of the copper foil to obtain a third intermediate.

[0095] S400, pressing the third intermediate (single-layer graphene-copper foil) as follows Figure 2 As shown in the first metal mask, the copper foil needs to be neatly laid flat on the glass slide in advance, and the first metal mask needs to be slowly pressed from one side. Be careful not to scratch the graphene on the surface of the copper foil during pressing. At the same time, the first metal mask needs to be seamlessly fitted with the copper foil to obtain graphene strips with clear edges. When etching with argon plasma gas later, it is necessary to pre-introduce argon gas to clean the cavity after vacuuming. After etching, remove the first metal mask, heat the copper foil at 160°C for 5 minutes, and you can clearly see the color change of the etched copper foil to obtain the fourth intermediate.

[0096] S500, press the fourth intermediate (graphene strip-copper foil) as follows Figure 3As shown in the second metal mask, it is necessary to strictly align the edge positioning mark when pressing, so that a small part of the second metal mask is pressed on the top of the graphene strip for subsequent testing, and then metal is evaporated in a thermal resistance evaporation coating machine to prepare the fifth intermediate containing the graphene metal electrode.

[0097] S600, spin-coating polymethyl methacrylate as a support layer on the fifth intermediate (electrode-graphene strip-copper foil), the thickness of the support layer is 5µm, if it is too thin, it is easy to be damaged in the subsequent transfer process, and if it is too thick, it will weaken the flexibility and affect the close adhesion of the subsequent graphene and the molecular film, and then slowly immerse it in a ferric chloride-hydrochloric acid solution, after etching the copper foil, it is washed in a hydrochloric acid aqueous solution to obtain a sixth intermediate (polymethyl methacrylate-gold electrode-graphene strip);

[0098] In order to reduce the introduction of impurities, in S610, before etching away the copper foil, the graphene on the back side of the copper foil of the fifth intermediate is etched using oxygen plasma gas.

[0099] S700, transferring the sixth intermediate from the aqueous solution to the second intermediate to obtain a molecular film phototransistor.

[0100] A molecular film phototransistor provided by the present invention is described below. The molecular film phototransistor described below and the method for preparing the molecular film phototransistor described above can be referred to each other.

[0101] like Figure 4 As shown, the present invention also provides a molecular film phototransistor, which is prepared based on the molecular film phototransistor preparation method as described above, comprising:

[0102] The substrate 1 (including the back gate); the metal electrode 2, the photosensitive molecular film 3, the graphene electrode 4 and the polymethyl methacrylate layer 5 are arranged in sequence from bottom to top.

[0103] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0104] 1. By introducing the metal mask technology and using the copper foil for growing graphene as the substrate for preparing the electrode, there is no need to replace the substrate when preparing the graphene electrode. The metal mask technology can effectively simplify the preparation process of the molecular film phototransistor, and quickly prepare graphene electrodes in batches, so that the overall molecular film phototransistor has the advantages of low preparation cost, short cycle and high success rate;

[0105] 2. By introducing a metal hollow mask to prepare graphene strips and graphene electrodes, no photoresist is used in this process, which can completely avoid the subsequent photoresist residue and the damage to graphene during the removal process, so that there is a clean and tidy contact interface between graphene and the metal electrode, which can further improve the performance of molecular film phototransistors;

[0106] 3. By using centimeter-sized transferred graphene strips as electrodes of molecular film phototransistors, multiple molecular film phototransistor array devices can be prepared simultaneously, achieving large-scale and low-cost production and integration;

[0107] 4. By transferring the graphene strips and the electrode-coated polymethyl methacrylate, which is subsequently covered on the upper surface of the molecular film, it can not only serve as a supporting layer for the graphene strips, but also has good optical transparency and corrosion resistance. The dense polymethyl methacrylate film can effectively isolate air and water, thereby significantly improving the life and performance stability of the molecular film phototransistor.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a molecular film phototransistor, characterized in that: The steps include: S100, spin coating a photoresist on a substrate, and sequentially performing an exposure process and an evaporation process on the substrate to obtain a first intermediate including a metal electrode; S200, self-assembling a photosensitive molecular film on the first intermediate to obtain a second intermediate; S300, pre-treating the copper foil by immersing it in acetic acid, rinsing the pre-treated copper foil with ultrapure water and ethanol, and placing the rinsed copper foil in a chemical vapor deposition tube furnace to obtain a third intermediate having a single-layer graphene grown thereon; S400, pressing a first metal mask on the third intermediate, and performing etching in a plasma gas environment to obtain a fourth intermediate including graphene strips; S500, pressing a second metal mask on the fourth intermediate, and evaporating metal to obtain a fifth intermediate including a graphene metal electrode; S600, spin-coating polymethyl methacrylate on the fifth intermediate, immersing in a ferric chloride hydrochloric acid solution, etching to remove the copper foil, and washing to obtain a sixth intermediate; S700, placing the sixth intermediate on the second intermediate to obtain a molecular film phototransistor.

2. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: The substrate includes one of silicon wafer, boron nitride or mica.

3. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: In the step S100, the roughness of the upper surface of the first intermediate is less than or equal to 1 nm.

4. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: In the step S200, the terminal connecting groups of the photosensitive molecules of the photosensitive molecular film include one of mercapto, sulfonic acid, pyrene or thiomethyl.

5. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: In the step S200, the molecular formula of the photosensitive molecule of the photosensitive molecular film is: 。 6. The method for preparing a molecular film phototransistor according to claim 5, characterized in that: The preparation process of photosensitive molecules is as follows: In a nitrogen environment, dibromodinitrobenzothiazole, iron powder and acetic acid are mixed and stirred at room temperature for 8 hours to 14 hours to obtain a first reaction solution; The first reaction solution was evaporated to remove the solvent, and then separated by column chromatography to obtain ; In a nitrogen environment, and oxalyl chloride were dissolved in dimethylformamide, and then hydrochloric acid was added, refluxed for 8 hours to 12 hours, and separated by rotary evaporation to obtain ; In a nitrogen environment, , 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)benzenethiol and tetrakis(triphenylphosphine)palladium are dissolved in a mixed solvent of ethylene glycol dimethyl ether and water, reacted at a temperature of 80° C. to 90° C. for 7 to 9 hours, cooled to room temperature, and the solvent is removed under pressure to obtain a second reaction solution; The second reaction solution was added to water and dichloromethane for extraction, and then anhydrous sodium sulfate was added for drying. The solvent was removed by rotary evaporation and separated by column chromatography to obtain ; Will Dissolve in dichloromethane solvent, add N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, and then add , obtaining a third reaction solution; The third reaction solution is purified and filtered to obtain a photosensitive molecule.

7. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: The plasma gas is argon.

8. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: In the step S500, the material of the graphene metal electrode includes one of gold, silver or platinum.

9. The method for preparing a molecular film phototransistor according to claim 1, characterized in that: The step S600 further includes: S610, using oxygen plasma gas to etch the back side of the fifth intermediate after spin coating of polymethyl methacrylate, to remove graphene on the back side of the fifth intermediate.

10. A molecular film phototransistor, characterized in that: The method for preparing a molecular film phototransistor according to any one of claims 1 to 9 comprises: The substrate, metal electrode, photosensitive molecular film, graphene electrode and polymethyl methacrylate layer are arranged in sequence from bottom to top.

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