A flexible perovskite thin film transistor and a preparation method thereof
By using full-printing technology to fabricate perovskite thin-film transistors on flexible substrates, the problems of large-area fabrication and solvent incompatibility have been solved, enabling the manufacturing of high-performance, low-cost flexible electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANKAI UNIV
- Filing Date
- 2026-04-21
- Publication Date
- 2026-07-10
AI Technical Summary
Existing technologies make it difficult to fabricate perovskite thin-film transistors on flexible substrates with large area and high quality. Furthermore, the incompatibility of perovskite materials with solvents in other functional layers leads to interface erosion and device performance degradation.
Using full-printing technology, perovskite thin-film transistors are fabricated on flexible substrates via microelectronic printing. Compatible perovskite precursor solutions and ion gel solutions are used, combined with ultraviolet ozone treatment and gradient annealing processes to achieve maskless patterned integration of each functional layer.
This has enabled the fabrication of large-area, high-quality perovskite thin-film transistors, reducing costs, improving material utilization, and enhancing the electrical performance and stability of the devices.
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Figure CN122373655A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flexible electronic device fabrication technology, and more specifically to a flexible perovskite thin-film transistor and its fabrication method. Background Technology
[0002] Flexible electronics technology is a core development direction in fields such as wearable devices, electronic skin, and flexible displays. As a key component, the fabrication process of flexible thin-film transistors (TFTs) directly affects the performance and cost of the devices. In recent years, metal halide perovskite materials have been regarded as ideal semiconductor channel materials for building next-generation high-performance flexible TFTs due to their excellent optoelectronic properties, such as high carrier mobility, tunable bandgap, and good solution processability.
[0003] Currently, the fabrication of flexible TFTs largely relies on traditional micro-nano fabrication processes such as photolithography and vapor deposition. While these methods offer high precision, they suffer from inherent drawbacks such as complex processes, expensive equipment, significant material waste, and difficulty in large-area production, failing to meet the future demands for low-cost, high-volume flexible electronics manufacturing. Microelectronic printing technologies (such as inkjet printing and aerosol printing), as an emerging patterning and device integration solution, offer significant advantages including simple processes, low cost, high material utilization, and applicability to large-area flexible substrate production. They are particularly suitable for maskless digital pattern deposition, making them an ideal path to achieving fully flexible electronic system manufacturing.
[0004] However, combining high-performance perovskite semiconductor materials with microelectronic printing technology to fabricate fully printed flexible transistors still faces significant challenges: Firstly, there are issues with film formation and stability: perovskite materials are sensitive to environmental factors (such as water and oxygen), and their stability in flexible thin film morphologies is insufficient. More critically, during the printing process, the crystallization kinetics of perovskite ink, from droplets to the formation of a uniform, dense, and fully covered high-quality semiconductor film, are difficult to control. The rapid and disordered crystallization process easily leads to pinholes, cracks, and grain boundary defects in the film, which not only damages the device but also results in significant performance inhomogeneity, severely limiting the yield and reliability of printed circuits.
[0005] Secondly, there are challenges in multilayer integration processes: fully printed transistors require the sequential printing and integration of multiple functional layers, including source / drain electrodes, semiconductor channels, dielectric layers, and gate electrodes. A core challenge in this process is solvent orthogonality: solvents in subsequent printed layers can easily erode, dissolve, or cause interfacial diffusion in the previously cured functional layers. For example, ionogels are ideal dielectric materials for achieving high capacitance and low voltage operation, but they are typically based on highly polar solvents (such as acetonitrile and DMSO), which can severely damage the underlying perovskite semiconductor channel layer during printing, leading to device malfunction.
[0006] Therefore, there is an urgent need in this field for an innovative fabrication process that can achieve large-area, patterned, high-quality fabrication of perovskite semiconductor layers on flexible substrates, while also ensuring film quality, environmental stability, and interface compatibility with other functional layers (especially high-polarity dielectric layers) during printing integration, thereby fabricating high-performance, high-yield, and structurally complete fully printed flexible perovskite thin-film transistors. Summary of the Invention
[0007] In view of this, the present invention provides a method for fabricating flexible perovskite thin film transistors based on full-printing technology. This method aims to solve the problems of complex process flow, high cost and difficulty in large-area production in traditional processes. In particular, it addresses the problems of interface erosion, miscibility and device performance degradation caused by incompatible solvents of various functional layers in full-printing technology. It provides a high-capacitance dielectric layer solution that can be printed compatible with perovskite semiconductor layers, and finally realizes a low-operating-voltage, high-performance full-printed transistor on a flexible substrate.
[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for fabricating a flexible perovskite thin-film transistor includes the following steps: (1) Prepare perovskite precursor solution; (2) Prepare iontophoresis gel solution; (3) Clean the flexible substrate and perform surface treatment; (4) Print patterned electrodes on a flexible substrate to serve as the source and drain, respectively; (5) Print a patterned perovskite thin film on a substrate with printed electrodes as a semiconductor channel layer; (6) Print an ion gel on another independent flexible substrate, and after curing, transfer it to the perovskite film as a dielectric layer; (7) Print electrodes on the dielectric layer as gates to form a flexible perovskite thin film transistor.
[0009] Preferably, the perovskite precursor solution in step (1) comprises: selected from RNH3 + CH3NH3 + NH2CH=NH2 + Cs + At least one cation from Pb; 2+ Sn 2+ At least one divalent metal cation from Br; and at least one divalent metal cation from Br - I - Cl - SCN - CH3COOH - At least one anion in it.
[0010] Preferably, the solvent of the perovskite precursor solution in step (1) is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, γ-butyrolactone, γ-valerolactone, N-methylpyrrolidone, isopropanol, methylamine acetate ionic liquid, acetonitrile, 2-mercaptoethanol, 1,3-dimethyl-2-imidazolinone, ethanol and n-butanol.
[0011] Preferably, the concentration of the perovskite precursor solution, calculated as divalent cations, is 0.05 mol / L to 0.4 mol / L.
[0012] Preferably, the ionic gel in step (2) comprises a polymer, an ionic liquid, and an organic solvent, in a mass ratio of polymer: ionic liquid: organic solvent = 1:(0.3-1.2):8; The polymer is selected from one or more of polyvinylidene fluoride-co-hexafluoropropylene, polyvinyl alcohol, polyurethane, polyethylene oxide, polyethylene glycol and polymethyl methacrylate; The ionic liquid comprises: at least one cation selected from 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, N-butyl-N-methylpyrrolidine, and trimethylpropylammonium; and at least one anion selected from bis(trifluoromethanesulfonyl)imide, trifluoromethanesulfonate, tetrafluoroborate, hexafluorophosphate, and dicyandiamide; The organic solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, γ-butyrolactone, γ-valerolactone, N-methylpyrrolidone, acetone, acetonitrile, tetrahydrofuran, and ethanol.
[0013] Preferably, the flexible substrate in step (3) is selected from one of polyimide, polyethylene terephthalate and polyethylene naphthalate; the surface treatment is ultraviolet ozone treatment.
[0014] Preferably, the printing in steps (4)-(7) all adopt microelectronic printing technology.
[0015] Furthermore, in steps (4) and (7), the printing line spacing is 200μm, the printing speed is 2-5mm / s, and the air pressure is 100-130kPa. In step (4), the annealing temperature is 150℃ and the time is 30min, and in step (7), the annealing temperature is 80℃ and the time is 45min. The perovskite film printing speed in step (5) is 8-15 mm / s, the annealing temperature is 80-120℃, the time is 40-60 min, and the thickness of the obtained perovskite film is 200-500 nm. In step (6), the ionogel printing line spacing is 200 μm, the printing speed is 7-10 mm / s, the gas pressure is 0.2-0.7 kPa, and the curing is carried out using temperature gradient annealing. Specifically: After standing at room temperature for 3 minutes, place on a 45°C hot plate and heat for 30 minutes, then heat on an 80°C hot plate for 40 minutes, and finally anneal at a high temperature of 130°C for 20 minutes.
[0016] Preferably, the perovskite film in step (5) is prepared at room temperature by microelectronic printing technology at a printing speed of 8-15 mm / s, and then annealed at 80-120℃ for 40-60 min, resulting in a perovskite film thickness of 200-500 nm.
[0017] Preferably, the transfer in step (6) is a dry peel transfer, that is, the cured ion gel film is completely peeled off with sharp tweezers and laid flat on the perovskite film after annealing to ensure tight adhesion.
[0018] The present invention also protects flexible perovskite thin-film transistors prepared by any of the above methods, wherein the transistor has a top-gate bottom-contact structure and all functional layers are integrated on a flexible substrate by printing and transfer processes.
[0019] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a flexible perovskite thin-film transistor and its fabrication method, which has the following beneficial effects: The perovskite thin film prepared by the microelectronic printing technology of this invention can have an area of (3*3) cm. 2 And above, and the crystallinity is also good at the edges of large-area perovskite films; The flexible perovskite thin-film transistor prepared by this invention has all functional layers fabricated by microelectronic printing, perfectly realizing the fabrication and integration of maskless patterned thin films; This invention solves the problem of uneven crystallization quality in the preparation of large-area perovskite thin films on flexible substrates by spin coating using microelectronic printing technology; Compared with traditional methods such as blade coating, spray coating, and spin coating, this invention reduces the cost of preparing large-area perovskite thin films and improves material utilization; moreover, the prepared flexible perovskite thin film transistors have excellent electrical properties such as high carrier mobility. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the flexible perovskite thin-film transistor of Embodiment 1 of the present invention; Figure 2 This is a physical image of the perovskite thin film prepared by microelectronic printing technology in Embodiment 1 of the present invention; Figure 3 This is a physical image of the perovskite thin-film transistor fabricated by microelectronic printing technology in Embodiment 1 of the present invention; Figure 4 This is the transfer characteristic curve of the flexible perovskite thin-film transistor of Embodiment 1 of the present invention.
[0022] In the figure, 1 is the gate electrode; 2 is the ion gel dielectric layer; 3 is the perovskite thin film; 4 is the source and drain electrodes; and 5 is the flexible substrate. Detailed Implementation
[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0024] Example 1 The method for fabricating flexible perovskite thin-film transistors based on full-printing technology includes the following specific steps: (1) Preparation of perovskite precursor solution: Prepare a solution with chemical composition R2A n-1 B n X 3n+1 A perovskite precursor solution of type 1, wherein R is PEA + , A is MA + B is Pb 2+ X is I - and Br - The mixture is a mixture of DMF and GVL in solvent; (2) Preparation of ionogel solution: Prepare an ionogel solution with PVDF as the polymer network, [EMIM][TFSI] as the ionic liquid and acetone as the organic solvent; (3) Substrate preparation: The flexible polyimide (PI) substrate was placed in deionized water, isopropanol, acetone and ethanol in sequence, ultrasonically cleaned for 20 min, dried with high-purity nitrogen, and then treated with ultraviolet-ozone (UV-O3) for 15 min. (4) Printing source and drain electrodes: Using microelectronic printing technology, conductive silver paste is printed on the PI substrate according to the preset pattern (printing line spacing is 200μm, printing speed is 3mm / s, and air pressure is 120kPa) to form source and drain electrodes, and then subjected to low temperature annealing at 150℃ for 30min. (5) Printing semiconductor channel layer: The substrate with printed electrodes is preheated to 45°C, and a patterned perovskite film is printed at a speed of 10 mm / s. Then, it is annealed at 100°C for 50 min to obtain a perovskite film with a thickness of about 350 nm. (6) Printing and transferring dielectric layer: The ion gel prepared in step (2) is patterned and printed onto another blank PI substrate (auxiliary substrate) treated with ultraviolet ozone (printing line spacing is 200 μm, printing speed is 8 mm / s, and gas pressure is 0.5 kPa). After gradient temperature annealing (standing at room temperature for 3 min, then heated on a hot stage at 45°C for 30 min, then heated on a hot stage at 80°C for 40 min, and finally annealed at a high temperature of 130°C for 20 min), it is transferred flatly onto the perovskite film obtained in step (5) by dry peeling and transfer method as dielectric layer; (7) Printing gate electrode: A patterned silver gate electrode was fabricated on the ion gel dielectric layer using microelectronic printing method (printing line spacing of 200 μm, printing speed of 3 mm / s, and gas pressure of 120 kPa), and then subjected to low-temperature annealing at 80 °C for 45 min to complete the fabrication of the transistor.
[0025] Based on the steps described above, this embodiment successfully fabricated a flexible perovskite thin-film transistor using microelectronic printing. The transistor fabricated in this embodiment has a top-gate bottom-contact structure (e.g., Figure 1 As shown), physical diagrams of each functional layer are as follows: Figure 2 , Figure 3 As shown in the figure. Its transfer characteristic curve, as tested, is as follows: Figure 4 As shown, it exhibits good electrical performance.
[0026] Example 2 The difference between this embodiment and Example 1 is that the organic solvent for the perovskite precursor solution is a mixture of DMF and DMSO. The other steps are the same as in Example 1.
[0027] Example 3 The difference between this embodiment and Embodiment 1 is that the source and drain metals used are gold. The other steps are the same as in Embodiment 1.
[0028] Example 4 The difference between this embodiment and Embodiment 1 is that the perovskite precursor solution uses a mixed solvent of GVL and DMF, and the solute contains FA. + Pb 2+ I - and Br - The other steps are the same as in Example 1.
[0029] In summary, the present invention provides a method for fabricating flexible perovskite thin-film field-effect transistors based on full-printing technology, which solves the difficulty of fabricating large-area patterned perovskite thin films on flexible substrates in the prior art, and realizes the fabrication of fully printed flexible perovskite thin-film transistors, which greatly reduces the fabrication cost of flexible electronic devices, improves material utilization, and produces flexible perovskite thin-film transistors with good electrical performance.
[0030] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for fabricating a flexible perovskite thin-film transistor, characterized in that, Includes the following steps: (1) Prepare perovskite precursor solution; (2) Prepare iontophoresis gel solution; (3) Clean the flexible substrate and perform surface treatment; (4) Print patterned electrodes on a flexible substrate to serve as the source and drain, respectively; (5) Print a patterned perovskite thin film on a substrate with printed electrodes as a semiconductor channel layer; (6) Print an ion gel on another independent flexible substrate, and after curing, transfer it to the perovskite film as a dielectric layer; (7) Print electrodes on the dielectric layer as gates to form a flexible perovskite thin film transistor.
2. The method for fabricating a flexible perovskite thin-film transistor according to claim 1, characterized in that, The perovskite precursor solution in step (1) comprises: selected from RNH3 + CH3NH3 + NH2CH=NH2 + Cs + At least one cation from Pb; 2+ Sn 2+ At least one divalent metal cation from Br; and at least one divalent metal cation from Br - I - Cl - SCN - CH3COOH - At least one anion in it.
3. The method for fabricating a flexible perovskite thin-film transistor according to claim 1, characterized in that, The solvent of the perovskite precursor solution in step (1) is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, γ-butyrolactone, γ-valerolactone, N-methylpyrrolidone, isopropanol, methylamine acetate ionic liquid, acetonitrile, 2-mercaptoethanol, 1,3-dimethyl-2-imidazolinone, ethanol and n-butanol.
4. The method for fabricating a flexible perovskite thin-film transistor according to claim 1 or 2, characterized in that, The concentration of the perovskite precursor solution, calculated as divalent cations, is 0.05 mol / L to 0.4 mol / L.
5. The method for fabricating a flexible perovskite thin-film transistor according to claim 1, characterized in that, The ionic gel described in step (2) comprises a polymer, an ionic liquid, and an organic solvent, in a mass ratio of polymer: ionic liquid: organic solvent = 1:(0.3-1.2):8; The polymer is selected from one or more of polyvinylidene fluoride-co-hexafluoropropylene, polyvinyl alcohol, polyurethane, polyethylene oxide, polyethylene glycol and polymethyl methacrylate; The ionic liquid comprises: at least one cation selected from 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, N-butyl-N-methylpyrrolidine, and trimethylpropylammonium; and at least one anion selected from bis(trifluoromethanesulfonyl)imide, trifluoromethanesulfonate, tetrafluoroborate, hexafluorophosphate, and dicyandiamide; The organic solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, γ-butyrolactone, γ-valerolactone, N-methylpyrrolidone, acetone, acetonitrile, tetrahydrofuran, and ethanol.
6. The method for fabricating a flexible perovskite thin-film transistor according to claim 1, characterized in that, The flexible substrate mentioned in step (3) is selected from one of polyimide, polyethylene terephthalate and polyethylene naphthalate; the surface treatment is ultraviolet ozone treatment.
7. The method for fabricating a flexible perovskite thin-film transistor according to claim 1, characterized in that, The printing described in steps (4) to (7) all employ microelectronic printing technology.
8. The method for fabricating a flexible perovskite thin-film transistor according to claim 7, characterized in that, In steps (4) and (7), the printing line spacing is 200μm, the printing speed is 2-5mm / s, and the air pressure is 100-130kPa. In step (4), the annealing temperature is 150℃ and the time is 30min, and in step (7), the annealing temperature is 80℃ and the time is 45min. The perovskite film printing speed in step (5) is 8-15 mm / s, the annealing temperature is 80-120℃, the time is 40-60 min, and the thickness of the obtained perovskite film is 200-500 nm. In step (6), the ionogel printing line spacing is 200 μm, the printing speed is 7-10 mm / s, the gas pressure is 0.2-0.7 kPa, and the curing is carried out using temperature gradient annealing. Specifically: After standing at room temperature for 3 minutes, place on a 45°C hot plate and heat for 30 minutes, then heat on an 80°C hot plate for 40 minutes, and finally anneal at a high temperature of 130°C for 20 minutes.
9. The method for fabricating a flexible perovskite thin-film transistor according to claim 1, characterized in that, The transfer described in step (6) is a dry stripping transfer.
10. A flexible perovskite thin-film transistor prepared by the method according to any one of claims 1-9.