Intrinsic stretchable phototransistor based on semiconductor film and preparation method thereof

Abstract

The invention relates to an intrinsic stretchable phototransistor based on a semiconductor film and a preparation method thereof. The preparation method comprises the following steps: preparing a gold nanoparticle-silver nanowire / polydimethylsiloxane stretchable electrode; preparing a mixed semiconductor solution for air / water interface self-assembly; dropwise adding the mixed semiconductor solution into a watch glass which is subjected to plasma treatment and contains deionized water, and volatilizing the solvent to form a rubber-state semiconductor film; after the semiconductor film is transferred and laminated to the stretchable electrode, an initial transistor is obtained, and the initial transistor is dried and annealed; preparing a dielectric layer on the initial transistor by using the PU solution through a spin-coating method; and blade-coating a liquid metal gate electrode on the dielectric layer to obtain the intrinsic stretchable photoelectric transistor. Compared with the prior art, the invention has the advantages of low cost, simple process, high transistor working reliability and the like.

Description

Technical Field

[0001] This invention relates to the field of flexible electronics technology, specifically to an intrinsically stretchable semiconductor thin film, and more particularly to an intrinsically stretchable phototransistor based on a semiconductor thin film and its fabrication method. Background Technology

[0002] Near-infrared (NIR) photodetector imaging systems have shown great potential in intelligent visualization applications such as night vision devices, non-destructive testing, active health monitoring, and optical communication networks. With the surge in demand for flexible electronics, rubber-like photodetectors capable of adapting to repeated mechanical deformation and accurately sensing high-quality signals have become a research hotspot. In this context, a key prerequisite for realizing tunable deformable photodetectors is that the photosensitive material must simultaneously possess high carrier mobility and strain-insensitive mechanical properties. Researchers have conducted extensive studies on inorganic semiconductors such as silicon and metal oxides, improving their mechanical tensile properties by introducing structures such as three-dimensional pop-up structures, serpentine interconnect structures, and kirigami-based structures.

[0003] Semiconductor polymers, with their intrinsic flexibility, tunable molecular structure, and solution processability, have become ideal building blocks for phototransistors. Efficient charge transport relies on a highly ordered crystalline structure, while amorphous and disordered regions primarily determine the material's mechanical stretchability. This contradiction significantly limits the simultaneous achievement of high mobility and stretchability in semiconductor polymers. Introducing trace molecular dopants has become a highly attractive strategy: expanding amorphous regions to enhance stretchability while simultaneously lowering transition barriers and suppressing trapped states to improve conductivity. However, insufficient stability and durability under high strain and repetitive stress still fail to meet practical requirements. Furthermore, combining conjugated polymers with elastomer matrices to prepare rubber-like polymer composites has proven to be a feasible technical path for fabricating intrinsically stretchable semiconductor films. Unfortunately, current nanoconfining strategies primarily rely on solution spin-coating, which greatly limits the realization of scalable and uniform fabrication.

[0004] Therefore, it is imperative to develop and explore a simple, reliable, practical, and applicable highly doped rubber-state semiconductor thin film that can be used in intrinsically stretchable phototransistors. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art by providing an intrinsically stretchable phototransistor based on a semiconductor thin film and its fabrication method. This method can prepare highly doped rubber-state semiconductor nanofilms at low cost and on a large scale through an air / water interface self-assembly process, and then obtain the intrinsically stretchable phototransistor through a simple device fabrication strategy.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: Step 1: Prepare a gold nanoparticle-silver nanowire / polydimethylsiloxane stretchable electrode; Step 2: Prepare a hybrid semiconductor solution for self-assembly at the air / water interface; Step 3: The mixed semiconductor solution is dropped into a petri dish containing deionized water that has been treated with plasma, and the solvent evaporates to form a rubbery semiconductor film. Step 4: After transferring and laminating the semiconductor thin film onto the stretchable electrode, an initial transistor is obtained, and the initial transistor is subjected to drying and annealing treatment. Step 5: The PU solution is spin-coated onto the initial transistor to prepare a dielectric layer; Step 6: Apply liquid metal gate electrodes to the dielectric layer to obtain an intrinsically stretchable phototransistor.

[0007] Further, step one includes: A silver nanowire solution was patterned and deposited onto a glass slide using a drop casting method through a mask, followed by drying and heat treatment. A polydimethylsiloxane solution was spin-coated to completely cover the silver nanowire pattern and then cured to form a solid film. A stretchable silver nanowire / polydimethylsiloxane electrode was prepared by peeling a solid film off a glass slide. Gold nanoparticles were deposited on the surface of silver nanowires via a galvanic cell displacement reaction to obtain a gold nanoparticle-silver nanowire / polydimethylsiloxane stretchable electrode.

[0008] Furthermore, the preparation of the polydimethylsiloxane solution is specifically as follows: A polydimethylsiloxane solution was prepared by mixing dimethylsiloxane with a crosslinking agent at a ratio of (10~20):1. The silver nanowires are dispersed in isopropanol, with 1g of 1% mass fraction silver nanowires dispersed in 10-12g of isopropanol.

[0009] Furthermore, the gold nanoparticles are deposited using an aqueous solution of chloroauric acid.

[0010] Furthermore, the mixed semiconductor solution includes a DPP-TT semiconductor solution, a doped small molecule F4TCNQ solution, and an elastomer PU solution.

[0011] Furthermore, in the mixed semiconductor solution, the solvent of the DPP-TT semiconductor solution is a mixed solvent of chloroform and o-dichlorobenzene, with a volume ratio of (8~9):(2~1); the solvent of the doped small molecule F4TCNQ solution is chloroform; and the solvent of the elastomer PU solution is tetrahydrofuran.

[0012] Furthermore, in the mixed semiconductor solution, the volume ratio of the DPP-TT semiconductor solution, the doped small molecule F4TCNQ solution, and the elastomer PU solution is 98:20:5.

[0013] Furthermore, in step four, the annealing temperature is 50~80℃.

[0014] Furthermore, in the PU solution of step five, the mass of PU is 75~150mg, the solvent is tetrahydrofuran, and the volume is 1~2mL.

[0015] The present invention also provides an intrinsically stretchable phototransistor based on a semiconductor thin film prepared according to the preparation method described above.

[0016] The fabrication principle of this invention is as follows: A highly doped rubber-state semiconductor mixed solution suitable for self-assembly at the air-water interface is prepared. Under the Marangoni effect, this solution rapidly spreads on the water surface, triggering rapid solvent evaporation, thereby forming a uniform rubber-state semiconductor film. A stretchable electrode is fabricated by patterned deposition of silver nanowires, spin-coating and curing PDMS followed by exfoliation, and then depositing gold nanoparticles via a galvanic cell displacement reaction, ultimately obtaining an AuNPs-AgNWs / PDMS composite electrode. Finally, the device is integrated by transferring the semiconductor film to the electrode and drying and annealing it, followed by spin-coating a PU dielectric layer and then scraping a liquid metal gate, resulting in a near-infrared phototransistor with both high electrical performance and excellent mechanical stretchability.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention utilizes the Marangoni effect-driven air / water interface self-assembly technology, which enables the mixed semiconductor solution to rapidly and autonomously spread and form a film. The process steps are simplified, no complex equipment is required, and it has good scalability and uniformity, providing a feasible path for the large-area, large-scale preparation of high-performance rubber-state semiconductor thin films.

[0018] 2. The hybrid semiconductor solution of the present invention includes a DPP-TT semiconductor solution, a doped small molecule F4TCNQ solution, and an elastomer PU solution. Through the synergistic effect of chemical doping and physical nanoconfinement, while introducing molecular dopants to expand the amorphous region and enhance stretchability, it also improves carrier mobility, thereby achieving a unity of optoelectronic performance and mechanical flexibility.

[0019] 3. The nano-network semiconductor thin film prepared by the present invention can be firmly bonded to the electrodes and dielectric layer. The interface bonding is strengthened by secondary annealing, so that the device can maintain a high signal-to-noise ratio and charge collection efficiency under repeated deformation, which significantly improves the working reliability and durability of the intrinsic stretchable phototransistor. Attached Figure Description

[0020] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2 This is a schematic diagram illustrating the preparation of semiconductor thin films according to the present invention; Figure 3 These are AFM images of the rubber-state semiconductor thin film in an embodiment of the present invention; Figure 4 These are scanning electron microscope (SEM) images of the rubber-state semiconductor thin film before (4a) and after (4b) gold sputtering in the embodiments of the present invention; Figure 5 This is a schematic diagram of an intrinsically stretchable phototransistor based on a semiconductor thin film in an embodiment of the present invention; Figure 6 These are optical images of the rubber-state semiconductor thin film under different degrees of stretching in the embodiments of the present invention; Figure 7 This is the transfer curve of the intrinsically stretchable phototransistor based on semiconductor thin film in the embodiments of the present invention; Figure 8 This illustrates the variation of transistor mobility under different stretching directions in embodiments of the present invention: 8a represents stretching along the channel length direction; 8b represents stretching perpendicular to the channel length direction. Figure 9 These are the photoresponse transfer curves of the transistor in this embodiment of the invention under 808 nm near-infrared light and different light intensities; Figure 10 The embodiments of the present invention are based on 808 nm near-infrared light and 5.08 mW / cm². 2 The variation of responsivity R and detectivity D* with strain of 0-50% along the channel length and vertical direction under fixed light intensity irradiation. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0022] like Figure 1 As shown, this invention provides a method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film, comprising the following steps: Step 1: Preparation of AuNPs-AgNWs / PDMS (Gold Nanoparticles-Silver Nanowires / Polydimethylsiloxane) Stretchable Electrode: First, silver nanowires (AgNWs) are patterned and deposited on a glass slide, dried, and heat-treated to enhance conductivity; then, PDMS (polydimethylsiloxane) solution is spin-coated, cured, and exfoliated to obtain the AgNWs / PDMS (silver nanowires / polydimethylsiloxane) electrode; finally, gold nanoparticles are deposited on the surface of the silver nanowires through a galvanic cell displacement reaction, and after cleaning and drying, the stretchable electrode is prepared.

[0023] Specifically, a patterned silver nanowire solution was deposited onto a clean glass slide using a drop casting method and a mask prepared by a programmable die cutter. The deposited sample was dried at 40–60 °C for 10–15 min. Subsequently, the patterned silver nanowires on the glass slide were heated at 80–100 °C for 20–30 min to enhance their conductivity. Then, a PDMS solution was spin-coated at 300–500 rpm for 20–40 s to completely cover the silver nanowire pattern, and cured at 60–90 °C for 1–2 h to form a solid film. The cured PDMS-silver nanowire composite structure was then peeled off from the glass slide to obtain a stretchable AgNWs / PDMS electrode. To further form a gold nanoparticle coating on the exposed silver nanowire surface, the electrode was immersed in a 0.5 mM chloroauric acid aqueous solution at room temperature for 2–5 min, achieving gold deposition through a silver-gold galvanic cell displacement reaction. The electrode was then rinsed with deionized water and immersed in 28% ammonia water for 1-3 minutes to dissolve the byproduct silver chloride layer. Finally, it was rinsed with deionized water, dried with a nitrogen gun, and heated at 90°C for 2-5 minutes to dehydrate, thus completing the preparation of the AuNPs-AgNWs / PDMS stretchable electrode.

[0024] The main agent of the PDMS elastomer is dimethylsiloxane, and the mixing ratio of dimethylsiloxane to crosslinking agent is (10~20):1 to prepare the PDMS solution. Silver nanowires are dispersed in isopropanol. 1g of 1% mass fraction silver nanowires is dispersed in 10~12g of isopropanol, with stirring time of 5~15min, centrifugation speed of 500~2000rpm, and centrifugation time of 2~6min.

[0025] Step two involves preparing a hybrid semiconductor solution for air / water interface self-assembly. This hybrid semiconductor solution comprises three components: DPP-TT semiconductor is dissolved in a chloroform / o-dichlorobenzene mixed solvent to obtain a DPP-TT semiconductor solution, with a volume ratio of chloroform to o-dichlorobenzene of (8~9):(2~1); F4TCNQ is dissolved in chloroform to obtain a doped small molecule F4TCNQ solution; and PU is dissolved in tetrahydrofuran to obtain an elastomer PU solution. Each solution is heated and stirred until dissolved. Subsequently, the three solutions are mixed at a specific volume ratio and homogenized by stirring to obtain a homogeneous hybrid semiconductor solution suitable for air / water interface self-assembly.

[0026] Among them, DPP-TT (Diketopyrrolopyrrole-Tetrathienoacene) solution is a conjugated polymer solution based on the diketopyrrolopyrrole (DPP) structure. Its molecular structure forms an ordered arrangement through π-π stacking and intermolecular interactions, endowing the material with excellent charge transport properties; F4TCNQ (2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane) solution is a strong electron-withdrawing small molecule material with excellent electron transport ability and interface regulation characteristics; PU (Polyurethane) solution is a polymer material formed by the stepwise polymerization reaction of isocyanate and polyol, with excellent mechanical properties and chemical stability.

[0027] In the preparation method of the mixed semiconductor solution, the mass of DPP-TT is 5-10 mg, the volume of the mixed solvent of chloroform and o-dichlorobenzene is 1-2 mL, and the mixture is stirred at 50-80℃ for 10-30 min; the mass of F4TCNQ is 0.5-1 mg, the volume of chloroform is 1-2 mL, and the mixture is stirred at 40-60℃ for 10-30 min; the mass of PU is 25-50 mg, the volume of tetrahydrofuran is 1-2 mL, and the mixture is stirred at 80-120℃ for 3-4 h. The three solutions are mixed at a volume ratio of (DPP-TT:F4TCNQ:PU) = 98:20:5, and stirred at 1000-1500 rpm at room temperature for 1-2 h to obtain a semiconductor solution suitable for self-assembly at the air / water interface. Based on the above mixing volume ratio, a highly doped rubber-state semiconductor thin film can be formed, with the optimal ratio being 2 wt% F4TCNQ + 20 wt% PU.

[0028] Step 3, as Figure 2 As shown, a mixed semiconductor solution was dropped into a plasma-treated petri dish containing deionized water. The amount of mixed semiconductor solution added was 5–10 μL, and the diameter of the petri dish was 2.5–4 cm. The solvent evaporated to form a highly doped rubber-state semiconductor film. The AFM image of this semiconductor film is shown below. Figure 3 As shown, the microphase-separated nanonetwork structure observed in the rubbery semiconductor film is caused by the surface energy difference between the DPP-TT and PU components.

[0029] The above process is based on the inherent compatibility between molecular dopants and polymer systems, as well as the synergistic effect of physical nanoconfining and chemical doping. By precisely controlling the chemical composition and photoelectric properties of the ternary system composed of dopants, elastomers, and semiconductors, highly doped rubber-state semiconductor nanofilms that can be fabricated on a large area can be realized.

[0030] Step four: Transfer the semiconductor thin film to a stretchable electrode and dry and anneal it. The scanning electron microscope image of the semiconductor thin film after annealing is shown below. Figure 4 As shown in the figure, the nanonet responsible for charge transport is mainly composed of the semiconductor polymer DPP-TT, which is consistent with the morphology observed by AFM.

[0031] In this process, a semiconductor thin film is transferred to a stretchable electrode to create an initial transistor device. This device is first air-dried overnight, and then subjected to a second annealing process on a hot plate to ensure that any residual moisture is completely removed. The second annealing temperature on the hot plate is 50~80℃.

[0032] Step 5, spin-coating the PU dielectric layer: spin-coat the prepared PU solution onto the transistor channel obtained in step 4, and then place it on a heating plate for annealing.

[0033] The PU solution contains 75-150 mg of PU and 1-2 mL of tetrahydrofuran solvent. The PU solution is spin-coated onto the channel layer at 2000-4000 rpm for 40-60 seconds, followed by annealing at 60-90°C for 1-2 hours.

[0034] Step six involves coating the liquid metal gate electrode to finally fabricate the intrinsically stretchable phototransistor. A schematic diagram of the final transistor device is shown below. Figure 5 As shown, it includes, from bottom to top, a PDMS substrate 1, an AuNPs-AgNWs electrode layer 2, a semiconductor thin film 3, a PU dielectric layer 4, and a liquid metal gate electrode 5.

[0035] Example 1 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1) Take 1g of 1wt% silver nanowires and disperse them in 10g of isopropanol. Stir thoroughly for 10min to mix evenly, and centrifuge at 1000rpm for 3min to obtain a silver nanowire dispersion. The mixing ratio of dimethylsiloxane and crosslinking agent is 10:1 to prepare a PDMS solution.

[0036] (2) Using a drop casting method, silver nanowire solution was patterned and deposited onto a clean glass slide using a mask prepared by a programmable dicing machine. The deposited sample was dried at 60°C for 15 min. PDMS solution was spin-coated at 500 rpm for 20 s to completely cover the silver nanowire pattern, and then cured at 60°C for 1 h to form a solid film. The cured PDMS and silver nanowire composite structure was peeled off from the glass slide to obtain a stretchable AgNWs / PDMS electrode.

[0037] (3) The electrode was immersed in a 0.5 mM chloroauric acid aqueous solution for 3 min to achieve gold deposition through a silver-gold galvanic cell displacement reaction. The electrode was then rinsed with deionized water and soaked in 28% ammonia water for 3 min to dissolve the byproduct silver chloride layer. Finally, the electrode was rinsed with deionized water, dried with a nitrogen gun, and heated to 90°C for 3 min to remove water, thus completing the preparation of the AuNPs-AgNWs / PDMS stretchable electrode.

[0038] (4) Weigh 5 mg DPP-TT and add it to 1 mL of a mixed solvent of chloroform and o-dichlorobenzene (chloroform: o-dichlorobenzene = 9:1), and stir at 60 °C for 30 min; weigh 0.5 mg F4TCNQ and add it to 1.0 mL of chloroform, and stir at 55 °C for 30 min; weigh 25 mg PU and add it to 1 mL of tetrahydrofuran, and stir at 90 °C for 3 h. Mix 98 μL DPP-TT solution, 20 μL F4TCNQ solution, and 5 μL PU solution, and stir at 1000 rpm at room temperature for 1.5 h to obtain a mixed semiconductor solution suitable for self-assembly at the air / water interface.

[0039] (5) Take 7 μL of mixed semiconductor solution and drop it into the plasma-treated water interface. After the solvent evaporates, transfer the film to the stretchable electrode and dry it overnight at room temperature. Then place it on a heating plate at 60°C for secondary drying.

[0040] (6) Dissolve 75 mg of PU in 1 mL of tetrahydrofuran to form a PU solution. Spin coat the PU solution onto the channel layer at 3000 rpm for 60 s. Then anneal at 80 °C for 1 h to obtain the PU dielectric layer.

[0041] (7) A liquid metal gate electrode was coated on the prepared PU dielectric layer by a blade coating method, and an intrinsic stretchable phototransistor based on a semiconductor thin film was finally obtained.

[0042] (8) Fix the device on the probe stage, apply a voltage of -30V to the source and drain electrodes, and a bias voltage of -50V. Then test the electrical performance of the transistor under dark conditions.

[0043] (9) Use 808nm near-infrared light (light intensity fixed at 5.08mW / cm²). 2 The intrinsically stretchable transistor was irradiated to perform a photoresponse test.

[0044] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.51 cm⁻¹. 2 / (V・s), the on-state current is 8.3E-6A, the responsivity R is 2.02A / W, and the detectivity D * It is 1.19E11 Jones.

[0045] Example 2 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1) Take 1g of 1wt% silver nanowires and disperse them in 12g of isopropanol. Stir thoroughly for 15min to mix evenly, and centrifuge at 500rpm for 6min to obtain a silver nanowire dispersion. The mixing ratio of dimethylsiloxane and crosslinking agent is 20:1 to prepare a PDMS solution.

[0046] (2) Using a drop casting method, silver nanowire solution was patterned and deposited onto a clean glass slide using a mask prepared by a programmable die cutter. The deposited sample was dried at 40°C for 15 min. PDMS solution was spin-coated at 300 rpm for 40 s to completely cover the silver nanowire pattern, and then cured at 90°C for 1 h to form a solid film. The cured PDMS and silver nanowire composite structure was peeled off from the glass slide to obtain a stretchable AgNWs / PDMS electrode.

[0047] (3) The electrode was immersed in a 0.5 mM chloroauric acid aqueous solution for 5 min to achieve gold deposition through a silver-gold galvanic cell displacement reaction. The electrode was then rinsed with deionized water and soaked in 28% ammonia water for 2 min to dissolve the byproduct silver chloride layer. Finally, the electrode was rinsed with deionized water, dried with a nitrogen gun, and heated to 90°C for 5 min to remove water, thus completing the preparation of the AuNPs-AgNWs / PDMS stretchable electrode.

[0048] (4) Weigh 10 mg DPP-TT and add it to 2 mL of a mixed solvent of chloroform and o-dichlorobenzene (chloroform: o-dichlorobenzene = 9:1), and stir at 80 °C for 10 min; weigh 1 mg F4TCNQ and add it to 2.0 mL of chloroform, and stir at 60 °C for 15 min; weigh 50 mg PU and add it to 2 mL of tetrahydrofuran, and stir at 120 °C for 3 h. Take 98 μL DPP-TT solution, 20 μL F4TCNQ solution and 5 μL PU solution and mix them, and stir at 1500 rpm at room temperature for 1 h to obtain a mixed semiconductor solution suitable for self-assembly at the air / water interface.

[0049] (5) Take 10 μL of mixed semiconductor solution and drop it into the plasma-treated water interface. After the solvent evaporates, transfer the film to the stretchable electrode and dry it overnight at room temperature. Then place it on a heating plate and dry it again at 80°C.

[0050] (6) Dissolve 150 mg of PU in 2 mL of tetrahydrofuran to form a PU solution. Spin coat the PU solution onto the channel layer at 4000 rpm for 40 s. Then anneal at 90 °C for 1 h to obtain the PU dielectric layer.

[0051] (7) A liquid metal gate electrode was coated on the prepared PU dielectric layer by a blade coating method, and an intrinsic stretchable phototransistor based on a semiconductor thin film was finally obtained.

[0052] Example 3 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1) Take 1g of 1wt% silver nanowires and disperse them in 10g of isopropanol. Stir well for 5min to mix evenly, and centrifuge at 1000rpm for 2min to obtain a silver nanowire dispersion. The mixing ratio of dimethylsiloxane and crosslinking agent is 20:1 to prepare a PDMS solution.

[0053] (2) Using a drop casting method, silver nanowire solution was patterned and deposited onto a clean glass slide using a mask prepared by a programmable dicing machine. The deposited sample was dried at 50°C for 10 min. PDMS solution was spin-coated at 300 rpm for 40 s to completely cover the silver nanowire pattern, and then cured at 60°C for 2 h to form a solid film. The cured PDMS and silver nanowire composite structure was peeled off from the glass slide to obtain a stretchable AgNWs / PDMS electrode.

[0054] (3) The electrode was immersed in a 0.5 mM chloroauric acid aqueous solution for 2 min to achieve gold deposition through a silver-gold galvanic cell displacement reaction. The electrode was then rinsed with deionized water and soaked in 28% ammonia water for 1 min to dissolve the byproduct silver chloride layer. Finally, the electrode was rinsed with deionized water, dried with a nitrogen gun, and heated to 90°C for 2 min to remove water, thus completing the preparation of the AuNPs-AgNWs / PDMS stretchable electrode.

[0055] (4) Weigh 10 mg DPP-TT and add it to 2 mL of a mixed solvent of chloroform and o-dichlorobenzene (chloroform: o-dichlorobenzene = 8:2), and stir at 50 °C for 30 min; weigh 1 mg F4TCNQ and add it to 2.0 mL of chloroform, and stir at 40 °C for 30 min; weigh 50 mg PU and add it to 2 mL of tetrahydrofuran, and stir at 80 °C for 4 h. Take 98 μL DPP-TT solution, 20 μL F4TCNQ solution and 5 μL PU solution and mix them, and stir at 1000 rpm at room temperature for 2 h to obtain a mixed semiconductor solution suitable for self-assembly at the air / water interface.

[0056] (5) Take 5 μL of mixed semiconductor solution and drop it into the plasma-treated water interface. After the solvent evaporates, transfer the film to the stretchable electrode and dry it overnight at room temperature. Then place it on a heating plate at 50°C for secondary drying.

[0057] (6) Dissolve 150 mg of PU in 2 mL of tetrahydrofuran to form a PU solution. Spin coat the PU solution onto the channel layer at 2000 rpm for 60 s. Then anneal at 60 °C for 2 h to obtain the PU dielectric layer.

[0058] (7) A liquid metal gate electrode was coated on the prepared PU dielectric layer by a blade coating method, and an intrinsic stretchable phototransistor based on a semiconductor thin film was finally obtained.

[0059] Example 4 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1)-(7) are the same as in Example 1.

[0060] (8) Stretch the device by 10% along the channel length and fix it on the probe stage. Apply a voltage of -30V to the source and drain electrodes, while the bias voltage is -50V. Then test the electrical performance of the transistor under dark conditions.

[0061] (9) Stretch the device by 10% along the channel length and fix it on the probe stage, then use 808nm near-infrared light (light intensity fixed at 5.08mW / cm). 2 The intrinsically stretchable transistor was tested by irradiation.

[0062] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.48 cm⁻¹. 2 / (V・s), the on-state current is 8.5E-6A, the responsivity R is 1.93A / W, and the detectivity D * It is 0.93E11 Jones.

[0063] Example 5 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1)-(7) are the same as in Example 1.

[0064] (8) Stretch the device by 10% along the vertical channel length and fix it on the probe stage. Apply a voltage of -30V to the source and drain electrodes, while the bias voltage is -50V. Then test the electrical performance of the transistor under dark conditions.

[0065] (9) Stretch the device by 10% along the length of the vertical channel and fix it on the probe stage, then use 808nm near-infrared light (light intensity fixed at 5.08mW / cm). 2 The intrinsically stretchable transistor was tested by irradiation.

[0066] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.46 cm⁻¹. 2 / (V・s), the on-state current is 7.8E-6A, the responsivity R is 1.87A / W, and the detectivity D * It is 0.73E11 Jones.

[0067] Example 6 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1)-(7) are the same as in Example 1.

[0068] (8) Stretch the device by 30% along the channel length and fix it on the probe stage. Apply a voltage of -30V to the source and drain electrodes, while the bias voltage is -50V. Then test the electrical performance of the transistor under dark conditions.

[0069] (9) Stretch the device by 30% along the channel length and fix it on the probe stage, then use 808nm near-infrared light (light intensity fixed at 5.08mW / cm). 2 The intrinsically stretchable transistor was tested by irradiation.

[0070] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.42 cm⁻¹. 2 / (V・s), the on-state current is 7.5E-6A, the responsivity R is 1.66A / W, and the detectivity D * It is 0.69E11 Jones.

[0071] Example 7 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1)-(7) are the same as in Example 1.

[0072] (8) Stretch the device by 30% along the vertical channel length and fix it on the probe stage. Apply a voltage of -30V to the source and drain electrodes, while the bias voltage is -50V. Then test the electrical performance of the transistor under dark conditions.

[0073] (9) Stretch the device by 30% along the length of the vertical channel and fix it on the probe stage, then use 808nm near-infrared light (light intensity fixed at 5.08mW / cm). 2 The intrinsically stretchable transistor was tested by irradiation.

[0074] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.39 cm⁻¹. 2 / (V・s), the on-state current is 7.1E-6A, the responsivity R is 1.59A / W, and the detectivity D * It is 0.56E11 Jones.

[0075] Example 8 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1)-(7) are the same as in Example 1.

[0076] (8) Stretch the device by 50% along the channel length and fix it on the probe stage. Apply a voltage of -30V to the source and drain electrodes, while the bias voltage is -50V. Then test the electrical performance of the transistor under dark conditions.

[0077] (9) Stretch the device by 50% along the channel length and fix it on the probe stage, then use 808nm near-infrared light (light intensity fixed at 5.08mW / cm). 2 The intrinsically stretchable transistor was tested by irradiation.

[0078] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.36 cm⁻¹. 2 / (V・s), the on-state current is 5.8E-6A, the responsivity R is 1.36A / W, and the detectivity D * It is 0.66E11 Jones.

[0079] Example 9 A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film includes the following steps: (1)-(7) are the same as in Example 1.

[0080] (8) Stretch the device by 50% along the vertical channel length and fix it on the probe stage. Apply a voltage of -30V to the source and drain electrodes, while the bias voltage is -50V. Then test the electrical performance of the transistor under dark conditions.

[0081] (9) Stretch the device by 50% along the length of the vertical channel and fix it on the probe stage, then use 808nm near-infrared light (light intensity fixed at 5.08mW / cm). 2 The intrinsically stretchable transistor was tested by irradiation.

[0082] In this embodiment, the intrinsically stretchable transistor has a mobility of 0.31 cm⁻¹. 2 / (V・s), the on-state current is 5.3E-6A, the responsivity R is 1.29A / W, and the detectivity D * It is 0.42E11 Jones.

[0083] Figures 6-10 The diagram illustrates the test results obtained from the above embodiments under different degrees of stretching, different light intensities, and different stretching directions, demonstrating that the intrinsically stretchable phototransistor fabricated based on a highly doped rubber-state semiconductor thin film maintains excellent photoelectric performance and mechanical stability under stretching conditions. Specifically: Figure 6In this embodiment, the crack initiation strain of highly doped rubber-state semiconductor films was effectively controlled by optimizing the weight ratio of F4TCNQ to DPP-TT. The nano-network film obtained at the optimal ratio (2 wt% F4TCNQ + 20 wt% PU) exhibits excellent mechanical tensile properties and can maintain its morphology integrity under tensile strains of 30%, 60%, and 80%.

[0084] Figure 7 The transfer curve shown in this embodiment is that of an intrinsically stretchable phototransistor based on a highly doped rubber-state semiconductor thin film. The highly interconnected nano-network semiconductor polymer provides the current transport path, and the device exhibits excellent electrical performance: the on / off ratio reaches 10. 4 The average carrier mobility is 0.51 cm⁻¹. 2 V -1 s -1 And as Figure 8 As shown, the electrical performance of the device remains good whether it is stretched along the length of the channel or perpendicular to the length of the channel.

[0085] Figure 9 The image shows the photoresponse transfer curves of the intrinsically stretchable phototransistor based on a highly doped rubber-state semiconductor thin film under different illumination intensities of 808 nm near-infrared light in this embodiment. With increasing illumination intensity, the drain current increases and the threshold voltage shifts positively, both reflecting the modulating effect of the grating effect on photocarrier trapping in the semiconductor channel. Further verification of the near-infrared detection performance of the stretchable device under mechanical deformation, such as... Figure 10 As shown, when 0%, 10%, 30%, and 50% strain are applied along or perpendicular to the channel length direction, the near-infrared responsivity and detectivity of the nanofilm do not show significant attenuation, exhibiting ideal mechanical stability.

[0086] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film, characterized in that, Includes the following steps: Step 1: Prepare a gold nanoparticle-silver nanowire / polydimethylsiloxane stretchable electrode; Step 2: Prepare a hybrid semiconductor solution for self-assembly at the air / water interface; Step 3: The mixed semiconductor solution is dropped into a petri dish containing deionized water that has been treated with plasma, and the solvent evaporates to form a rubbery semiconductor film. Step 4: After transferring and laminating the semiconductor thin film onto the stretchable electrode, an initial transistor is obtained, and the initial transistor is subjected to drying and annealing treatment. Step 5: The PU solution is spin-coated onto the initial transistor to prepare a dielectric layer; Step 6: Apply liquid metal gate electrodes to the dielectric layer to obtain an intrinsically stretchable phototransistor.

2. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 1, characterized in that, Step one includes: A silver nanowire solution was patterned and deposited onto a glass slide using a drop casting method through a mask, followed by drying and heat treatment. A polydimethylsiloxane solution was spin-coated to completely cover the silver nanowire pattern and then cured to form a solid film. A stretchable silver nanowire / polydimethylsiloxane electrode was prepared by peeling a solid film off a glass slide. Gold nanoparticles were deposited on the surface of silver nanowires via a galvanic cell displacement reaction to obtain a gold nanoparticle-silver nanowire / polydimethylsiloxane stretchable electrode.

3. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 2, characterized in that, The preparation of the polydimethylsiloxane solution is as follows: A polydimethylsiloxane solution was prepared by mixing dimethylsiloxane with a crosslinking agent at a ratio of (10~20):

1. The silver nanowires are dispersed in isopropanol, with 1g of 1% mass fraction silver nanowires dispersed in 10-12g of isopropanol.

4. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 2, characterized in that, The gold nanoparticles were deposited using an aqueous solution of chloroauric acid.

5. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 1, characterized in that, The mixed semiconductor solution includes a DPP-TT semiconductor solution, a doped small molecule F4TCNQ solution, and an elastomer PU solution.

6. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 5, characterized in that, In the mixed semiconductor solution, the solvent of the DPP-TT semiconductor solution is a mixture of chloroform and o-dichlorobenzene in a volume ratio of (8~9):(2~1); the solvent of the doped small molecule F4TCNQ solution is chloroform; and the solvent of the elastomer PU solution is tetrahydrofuran.

7. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 5, characterized in that, In the mixed semiconductor solution, the volume ratio of the DPP-TT semiconductor solution, the doped small molecule F4TCNQ solution, and the elastomer PU solution is 98:20:

5.

8. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 1, characterized in that, In step four, the annealing temperature is 50~80℃.

9. The method for fabricating an intrinsically stretchable phototransistor based on a semiconductor thin film according to claim 1, characterized in that, In the PU solution of step five, the mass of PU is 75~150mg, the solvent is tetrahydrofuran, and the volume is 1~2mL.

10. An intrinsically stretchable phototransistor based on a semiconductor thin film, prepared by any one of the preparation methods according to claims 1-9.

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