High-quality tin-based perovskite thin films based on guanidinium-based additives and their transistor applications

Abstract

This invention discloses a high-quality tin-based perovskite thin film based on guanidine-based additives and its transistor application, belonging to the field of organic-inorganic metal halide perovskite field-effect transistor technology. Addressing the problems of pinholes, incomplete coverage, and poor crystallinity in perovskite thin films, this invention introduces guanidine-based additives with specific structures into the perovskite precursor solution. Utilizing the intermolecular interactions between these additives and the perovskite components, the crystallization process is controlled, thereby producing a high-crystallinity perovskite thin film with high crystallinity, few pinholes, and low roughness. Applying this film as a semiconductor layer in field-effect transistors significantly reduces carrier trap density, improves carrier mobility and current on / off ratio, and solves the key problems of low carrier mobility and poor performance in existing tin-based perovskite transistors. This is of great significance for promoting the industrialization of perovskite field-effect transistors.

Description

Technical Field

[0001] This invention belongs to the field of organic-inorganic metal halide perovskite field-effect transistor technology, specifically relating to a method for preparing highly crystalline perovskite thin films by regulating the preparation of such films using guanidine-based additives, and the application of such perovskite thin films in perovskite transistors. Background Technology

[0002] Field-effect transistors (FETs) are widely used as core components in electronic systems such as flat panel displays, integrated circuits, sensors, and memory. Metal halide perovskites, with their advantages of high carrier mobility, solution processability, and flexible compatibility, serve as the channel layer of FETs, providing a new path for building high-performance, low-cost next-generation optoelectronic devices and demonstrating great potential in fields such as wearable electronics.

[0003] However, fabricating high-performance and stable tin-based perovskite transistors remains a significant challenge. Uncontrolled crystallization processes lead to poor film quality, characterized by low coverage, random grain orientation, and high defect density (grain boundaries and vacancies), which disrupts carrier transport pathways and significantly reduces device performance.

[0004] This study successfully prepared highly crystalline perovskite thin films by using two guanidine-based additives to regulate the crystallization process through additive engineering. The nitrogen-containing lone pair electron groups and abundant hydrogen bonds of the guanidine group can suppress uncoordinated defects and ion migration, thereby improving structure and stability. Furthermore, the hydrophobicity of the molecule also enhances the environmental stability of the device. This study promoted the formation of uniform and dense perovskite thin films by regulating the nucleation and growth crystallization processes, ultimately resulting in a high-performance perovskite field-effect transistor. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing highly crystalline perovskite by regulating the process using guanidine-based additives, in order to solve the problems of various defects in the perovskite semiconductor layer of perovskite field-effect transistors, such as poor film quality, high carrier trap density, and insufficient electrical performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a method for preparing highly crystalline perovskite films by controlling the addition of guanidine-based additives. This highly crystalline perovskite film benefits from the passivation effect of the guanidine-based additives used. Compared to films without guanidine-based additives, films prepared with guanidine-based additives have fewer defects and higher crystallinity, improving carrier transport efficiency and thus enhancing the electrical properties of the film.

[0007] The additive molecules are of three types: one type is a halide salt formed by guanidine organic cations and different halogen anions; another type is a molecule containing guanidine and carbonyl derivatives; and the third type is a molecule containing guanidine and sulfonyl groups.

[0008] Furthermore, the guanidine organic cation forms halide salts with different halide anions, including guanidine iodide (GAI), guanidine hydrochloride (GACl), and guanidine bromide (GABr).

[0009] Furthermore, molecules containing guanidinyl and carbonyl derivatives include 4-guanidinobenzoic acid (4-Gua), 1-acetylguanidine (A-Gua), guanidinoacetic acid (GAA), 3-guanidinopropionic acid (3-GPA), 4-guanidinobutyric acid (4-GBA), 5-guanidinovalerate (5-GVA), and 6-guanidinohexanoic acid (6-GHA).

[0010] Furthermore, molecules containing guanidine and sulfonyl groups include sulfanilamide (SG), guanidine aminosulfonate (GuaSM), 1,1-dimethylguanidine sulfate (MGuS), 1-ethylguanidine sulfate (EGuS), 1-methylguanidine sulfate (DMGuS), and guanidine sulfate (GuS).

[0011] Furthermore, the crystal structure of the organic-inorganic metal halide perovskite is ABX3, where A is methylamine (MA). + ), formamidin (FA) + ) and cesium (Cs) + One or more of the cations, where B is tin (Sn). 2+ ) and lead (Pb 2+ Metal cations or mixtures thereof, where X is an iodide ion (I - ), chloride ions (Cl) - ), bromide ions (Br) - One or more of the following halogen anions:

[0012] Furthermore, the amount of halide salts formed by the guanidine organic cation and different halide anions and molecules with a guanidine group at the head and a carbonyl derivative at the tail is added is from 0.1 mol% to 10 mol% relative to the SnI2 content.

[0013] Furthermore, the thickness of the perovskite film is 10-500 nm.

[0014] Furthermore, in the application of perovskite thin films controlled by guanidine-based additives in field-effect transistors, the perovskite thin film serves as the semiconductor layer of the field-effect transistor.

[0015] Furthermore, the perovskite field-effect transistor prepared using the perovskite thin film regulated by guanidine additives as the semiconductor layer has the following structures: bottom gate top contact, bottom gate bottom contact, top gate bottom contact, and top gate top contact.

[0016] The field-effect transistor with perovskite thin film controlled by guanidine-based additives as semiconductor layer uses (Si) as gate, silicon dioxide (SiO2) as dielectric layer, and gold electrode (Au) as source and drain.

[0017] The beneficial effects of this invention are as follows:

[0018] 1. Significantly improved film quality: Compared with the control group without guanidine additives, the perovskite film prepared by this invention has lower surface roughness and higher crystallinity, larger grain size and fewer grain boundaries, and the film is more dense and uniform.

[0019] 2. Deep Defect Passivation and Antioxidant: The positively charged guanidinium cation and functional groups (carbonyl / sulfonyl) undergo strong coordination with SnI2, while the -NH group on the guanidinium group... 2+ with I - A hydrogen bond network is formed. This not only effectively passivates halogen vacancies and uncoordinated defects, reducing the trap state density, but also effectively suppresses Sn. 2+ Oxidation slows down the crystallization rate.

[0020] 3. Significantly improved device electrical performance: The high-quality semiconductor channel layer reduces carrier scattering centers and traps, enabling the fabricated perovskite field-effect transistors to exhibit higher carrier mobility and better current on / off ratio, providing a reliable technical path for the industrial application of perovskite transistors. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0022] Figure 1 This is a schematic diagram of a bottom-gate top-contact field-effect transistor structure for a perovskite field-effect transistor regulated by guanidine-based additives.

[0023] Among them, 1 is the source, 2 is the drain, 3 is the semiconductor layer, 4 is the dielectric layer, and 5 is the gate.

[0024] Figure 2 The morphology of FASnI3 perovskite films with added 0 mol%, 0.3 mol%, 0.6 mol%, 0.9 mol%, and 10 mol% guanidine iodide (GAI) is shown.

[0025] Figure 3 The image shows the morphology of the FASnI3 perovskite film with 0.6 mol% 4-guanidinobenzoic acid (4-Gua).

[0026] Figure 4 The image shows the morphology of the FASnI3 perovskite film with 0.6 mol% 1-acetylguanidine (A-Gua) added.

[0027] Figure 5 The image shows the morphology of the FASnI3 perovskite film with 0.6 mol% guanidinoacetic acid (GAA).

[0028] Figure 6 X-ray diffraction patterns of FASnI3 perovskite films with added 0 mol%, 0.3 mol%, 0.6 mol%, 0.9 mol%, and 10 mol% guanidine iodide (GAI).

[0029] Figure 7 X-ray diffraction pattern of FASnI3 perovskite film with 0.6 mol% 4-guanidinobenzoic acid (4-Gua), 0.6 mol% 1-acetylguanidine (A-Gua), and 0.6 mol% guanidinoacetic acid (GAA).

[0030] Figure 8 The infrared spectra are of guanidine iodide and guanidine iodide mixed with stannous iodide.

[0031] Figure 9 Transfer curves of bottom-gate top-contact field-effect transistors prepared from FASnI3 perovskite thin films containing 0 mol%, 0.3 mol%, 0.6 mol%, 0.9 mol%, and 10 mol% guanidine iodide (GAI).

[0032] Figure 10 Transfer curves of a bottom-gate top-contact field-effect transistor prepared from a FASnI3 perovskite thin film with 0.6 mol% 4-guanidinobenzoic acid (4-Gua) added.

[0033] Figure 11 Transfer curves of a bottom-gate top-contact field-effect transistor prepared from a FASnI3 perovskite thin film with 0.6 mol% 1-acetylguanidine (A-Gua) added.

[0034] Figure 12 Transfer curves of a bottom-gate top-contact field-effect transistor prepared from a FASnI3 perovskite thin film with 0.6 mol% guanidinoacetic acid (GAA) added. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only for explaining the invention and are not intended to limit the scope of protection of the invention.

[0036] This invention provides a method for preparing perovskite thin films by regulating the crystallization of guanidine-based additives and its application in transistors. The crystallization regulation originates from the effect of guanidine cations on Sn. 2+ Coordination effect and with I- Hydrogen bonding occurs.

[0037] Additive molecules fall into three categories: halide salts formed by guanidine organic cations and different halogen anions; molecules containing guanidine groups and carbonyl derivatives; and molecules containing guanidine groups and sulfonyl groups.

[0038] The guanidine organic cations formed by guanidine with different halogen anions are guanidine iodide (GAI), guanidine hydrochloride (GACl), and guanidine bromide (GABr).

[0039] Molecules containing guanidinyl and carbonyl derivatives. These include 4-guanidinobenzoic acid (4-Gua), 1-acetylguanidinylguanidine (A-Gua), guanidinoacetic acid (GAA), 3-guanidinopropionic acid (3-GPA), 4-guanidinobutyric acid (4-GBA), 5-guanidinovalerate (5-GVA), and 6-guanidinohexanoic acid (6-GHA).

[0040] Molecules containing guanidine and sulfonyl groups. These include sulfanilamide guanidine (SG), guanidine aminosulfonate (GuaSM), 1,1-dimethylguanidine sulfate (MGuS), 1-ethylguanidine sulfate (EGuS), 1-methylguanidine sulfate (DMGuS), and guanidine sulfate (GuS).

[0041] The crystal structure of organic-inorganic metal halide perovskites is ABX3, where A is methylamine (MA+) or formamidinium (FA). + ) and cesium (Cs) + One or more of the cations, where B is tin (Sn). 2+ ) and lead (Pb 2+ Metal cations or mixtures thereof, where X is an iodide ion (I - ), chloride ions (Cl) - ), bromide ions (Br) - One or more of the following halogen anions:

[0042] The method for preparing the ABX3 perovskite structure is a solution spin coating method, wherein the solution is prepared by fully dissolving the above components in a mixed solution of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) according to the stoichiometric ratio.

[0043] The perovskite field-effect transistors fabricated by controlling the structure of the perovskite thin film as the semiconductor layer using guanidine-based additives can be configured as bottom-gate-top contact, bottom-gate-bottom contact, top-gate-bottom contact, and top-gate-top contact.

[0044] The field-effect transistor described above, which uses guanidine-based additives to regulate the perovskite thin film as the semiconductor layer, uses silicon (Si) as the gate, silicon dioxide (SiO2) as the dielectric layer, and gold electrodes (Au) as the source and drain.

[0045] The molecular structures of GAI, GACl, GABr, 4-Gua, A-Gua, GAA, 3-GPA, 4-GBA, 5-GVA, SG, GuaSM, Mgus, EGus, DMGus, and GuS are shown in Table 1.

[0046] To better understand the purpose, structure, and function of this invention, the following description, in conjunction with the accompanying drawings, provides a more detailed account of a method for preparing highly crystalline perovskite using guanidine additives and its application in perovskite transistors.

[0047] Specific related embodiments of the present invention are as follows:

[0048] Example 1: A method for preparing perovskite thin films and transistor devices by controlling the addition of guanidine iodide (GAI).

[0049] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0050] Step (2) Additive introduction: Guanidine iodide (GAI) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, 0.9 mol%, and 10 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. At the same time, a portion of the precursor solution without added guanidine iodide (GAI) was reserved as a control group.

[0051] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0052] The morphology images of thin films prepared with different GAI contents are shown below. Figure 2 As shown, compared with the perovskite film prepared without GAI in the precursor solution, the film roughness is significantly reduced. The lowest root mean square roughness (RMS RMS) of the film is observed when the GAI addition is 0.6 mol%, at only 11.4 nm, indicating a smooth, dense film with fewer defects. This demonstrates that GAI additives can effectively improve the quality of perovskite films, resulting in dense tin-based perovskite films. However, in the 10 mol% perovskite film, the surface roughness increases to 40.8 nm, and numerous pinholes appear, indicating that excessive GAI is detrimental to the formation of dense, pinhole-free perovskite films.

[0053] The X-ray diffraction patterns of the thin films prepared at different GAI ratios are as follows: Figure 6As shown, compared with the perovskite films prepared without GAI in the precursor solution, the XRD diffraction intensities were significantly improved. Among them, the film with the strongest diffraction intensity and the smallest half-width was observed when the GAI addition was 0.6 mol%. The half-width of the (100) peak was only 0.25, indicating excellent crystallinity and orientation. This shows that the GAI additive can improve the crystallinity of the film and increase its crystallinity. However, when the GAI addition was 10 mol%, the XRD diffraction peak intensity decreased, the half-width increased, and impurity peaks appeared. This indicates that excessive GAI is not conducive to improving crystallinity and will produce impurity phases, affecting the film growth and the performance of transistor devices.

[0054] The infrared spectra of guanidine iodide and guanidine iodide mixed with stannous iodide are as follows: Figure 8 As shown, a blue shift can be observed in the Fourier transform infrared (FTIR) spectrum of the guanidinium N–H stretching vibration characteristic peak, indicating that the –NH group on the guanidinium group exhibits a strong blue shift. 2+ With I in SnI2 - Hydrogen bonds are formed between them, which effectively passivate iodine vacancy defects and reduce the trap state density of tin-based perovskite films; at the same time, the hydrogen bond network can suppress Sn 2+ Oxidation slows down the crystallization rate, increasing the grain size and reducing grain boundaries of the thin film, thereby improving the uniformity and density of the film. For field-effect transistor (FET) devices, this can reduce the number of carrier traps and scattering centers in the channel layer, resulting in higher hole mobility.

[0055] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++ The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0056] The transfer curve of the fabricated perovskite field-effect transistor is as follows: Figure 9 As shown, FASnI3 with 0.6 mol% GAI added exhibits the best performance as the semiconductor layer, achieving a field-effect transistor mobility of 2.98 cm⁻¹. 2 V -1 S -1 Compared to the FASnI3 transistor without GAI (mobility of 0.55 cm⁻¹), 2 V -1 S -1 The performance was improved by more than 4 times, while adding 10 mol% GAI would cause the device to have no off state.

[0057] Example 2: A method for preparing perovskite thin films and transistor devices by using 4-guanidinobenzoic acid (4-Gua) additive.

[0058] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0059] Step (2) Additive introduction: 4-Guidinobenzoic acid (4-Gua) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, and 0.9 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. At the same time, a portion of the precursor solution without the addition of 4-Guidinobenzoic acid (4-Gua) was reserved as a control group.

[0060] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0061] The morphology of the FASnI3 perovskite thin film prepared by 0.6 mol% 4-Gua modification is shown in the figure below. Figure 3 As shown, the root mean square roughness of the film is 8.44 nm, indicating that the film is flat, dense, and has few defects. This demonstrates that the 4-Gua additive can effectively improve the quality of perovskite films, thereby obtaining dense tin-based perovskite films.

[0062] X-ray diffraction pattern of 0.6 mol% 4-Gua modified FASnI3 perovskite thin film as shown in the figure. Figure 7 As shown, it exhibits good crystallinity and orientation. This indicates that the 4-Gua additive can improve the crystallinity and enhance the crystallinity of the thin film.

[0063] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++ The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0064] The transfer curve of the obtained FASnI3 perovskite field-effect transistor with 0.6 mol% 4-Gua is shown in the figure. Figure 10 As shown, its carrier mobility can reach 3.33 cm⁻¹. 2 V -1 S -1The current switching ratio is 10. 5 The threshold voltage is 12V.

[0065] Example 3: A method for preparing perovskite thin films and transistor devices by controlling the addition of 1-acetylguanidine (A-Gua).

[0066] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0067] Step (2) Additive introduction: 1-acetylguanidine (A-Gua) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, and 0.9 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. At the same time, a portion of the precursor solution without the addition of 1-acetylguanidine (A-Gua) was reserved as a control group.

[0068] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0069] The morphology of the FASnI3 perovskite thin film prepared by 0.6 mol% A-Gua modification is shown in the figure below. Figure 4 As shown, the root mean square roughness of the film is 12.9 nm, indicating that the film is flat, dense, and has few defects. This demonstrates that the A-Gua additive can effectively improve the quality of perovskite films, thereby obtaining dense tin-based perovskite films.

[0070] X-ray diffraction pattern of 0.6 mol% A-Gua modified FASnI3 perovskite thin film as shown in the figure. Figure 7 As shown, the film exhibits good crystallinity and orientation. This indicates that the A-Gua additive can improve the crystallinity and enhance the crystallinity of the thin film.

[0071] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++ The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0072] The transfer curve of the obtained FASnI3 perovskite field-effect transistor with 0.6 mol% A-Gua is shown in the figure. Figure 11As shown, its carrier mobility can reach 2.76 cm⁻¹. 2 V -1 S -1 The current switching ratio is 10. 5 The threshold voltage is 12V.

[0073] Example 4: A method for preparing perovskite thin films and transistor devices by controlling the addition of guanidinoacetic acid (GAA).

[0074] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0075] Step (2) Additive introduction: Guanidinoacetic acid (GAA) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, and 0.9 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. A portion of the precursor solution without added guanidinoacetic acid (GAA) was reserved as a control group.

[0076] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0077] The morphology of the FASnI3 perovskite thin film prepared by 0.6 mol% GAA modification is shown in the figure below. Figure 5 As shown, the root mean square roughness of the film is 8.76 nm, indicating that the film is flat, dense, and has few defects. This demonstrates that the GAA additive can effectively improve the quality of perovskite films, thereby obtaining dense tin-based perovskite films.

[0078] X-ray diffraction pattern of 0.6 mol% GAA-modified FASnI3 perovskite thin film as shown below Figure 7 As shown, the film exhibits good crystallinity and orientation. This indicates that the GAA additive can improve the crystallinity and enhance the crystallinity of the thin film.

[0079] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++ The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0080] The transfer curve of the obtained FASnI3 perovskite field-effect transistor with 0.6 mol% GAA is shown in the figure. Figure 12 As shown, its carrier mobility can reach 3.02 cm⁻¹. 2 V -1 S -1 The current switching ratio is 10. 5 The threshold voltage is 8V.

[0081] Example 5: A method for preparing perovskite thin films and transistor devices by using 3-guanidinopropionic acid (3-GPA) additive.

[0082] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0083] Step (2) Additive introduction: 3-guanidinopropionic acid (3-GPA) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, and 0.9 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. At the same time, a portion of the precursor solution without the addition of 3-guanidinopropionic acid (3-GPA) was reserved as a control group.

[0084] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0085] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++ The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0086] Example 6: A method for preparing perovskite thin films by controlling the addition of sulfanilamide guanidine (SG).

[0087] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0088] Step (2) Additive introduction: Sulfaguanidine (SG) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, and 0.9 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. A portion of the precursor solution without added sulfaguanidine (SG) was reserved as a control group.

[0089] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0090] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++ The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0091] Example 7:

[0092] A method for preparing perovskite thin films by controlling the addition of guanidine aminosulfonate (GuaSM) includes the following steps:

[0093] Step (1) Preparation of precursor solution: SnI2, FAI, and SnF2 were dissolved in a mixed solvent of DMF / DMSO (volume ratio of 4:1) and stirred at room temperature for 12 h to prepare an initial FASnI3 precursor solution of 0.25 M. The molar ratio of SnI2, FAI, and SnF2 was 1:1:0.06.

[0094] Step (2) Additive introduction: Guanidine aminosulfonate (GuaSM) was added to the above precursor solution at 0.3 mol%, 0.6 mol%, and 0.9 mol% relative to the molar amount of SnI2, and stirred until completely dissolved. A portion of the precursor solution without added guanidine aminosulfonate (GuaSM) was reserved as a control group.

[0095] Step (3) Thin film preparation: The above precursor solutions are deposited on the Si / SiO2 substrate by spin coating to form a wet film, and then annealed to obtain FASnI3 perovskite thin film.

[0096] Step (4) Device Fabrication and Testing: On the perovskite thin film prepared above, gold (Au) electrodes are deposited using a mask via vacuum evaporation to serve as the source and drain, thereby obtaining a bottom-gate top-contact field-effect transistor. The structure of this device is as follows: Figure 1 As shown, heavy doped silicon Si(p) ++The gate is made of SiO2, the dielectric layer is made of perovskite film, the active semiconductor layer is made of Au, and the source and drain are made of Au.

[0097] It is understood that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0098] The general formula of the halide salts formed by guanidine organic cations and different halide anions in this invention is shown below, where R is a halogen atom.

[0099]

[0100] The general formula of the molecule containing guanidine and carbonyl derivatives in this invention is shown below, wherein R1 and R2 are different substituents.

[0101]

[0102] The general formula of the molecule containing guanidinyl and sulfonyl groups in this invention is shown below, wherein R1, R2, R3, and R4 are different substituents.

[0103]

[0104] Table 1

[0105]

Claims

1. A method for preparing high-quality tin-based perovskite thin films based on guanidine-based additives, characterized in that, include: In the process of preparing the perovskite precursor solution, at least one guanidine-based additive is added; wherein the molecular structure of the guanidine-based additive contains a guanidine cation, and the amount of the guanidine-based additive added is 0.1% to 10% of the molar amount of the metal halide.

2. The preparation method according to claim 1, characterized in that, The guanidine-based additives are selected from at least one of the following compounds: (a) A halide salt formed by a guanidinium cation and a halide anion; (b) Molecules containing guanidine and carbonyl / carbonyl-derived groups; (c) Molecules containing guanidine and sulfonyl groups.

3. The preparation method according to claim 2, characterized in that, (a) Class halide salts include one or more of guanidine iodide (GAI), guanidine hydrochloride (GACl), and guanidine bromide (GABr); (b) Class molecules include one or more of 4-guanidinobenzoic acid (4-Gua), 1-acetylguanidine (A-Gua), guanidinoacetic acid (GAA), 3-guanidinopropionic acid (3-GPA), 4-guanidinobutyric acid (4-GBA), 5-guanidinovalerate (5-GVA), and 6-guanidinohexanoic acid (6-GHA); (c) Class molecules include one or more of sulfanilamide guanidine (SG), guanidine aminosulfonate (GuaSM), 1,1-dimethylguanidine sulfate (MGuS), 1-ethylguanidine sulfate (EGuS), 1-methylguanidine sulfate (DMGuS), and guanidine sulfate (GuS).

4. The preparation method according to claim 1, characterized in that, The perovskite has an ABX3 crystal structure, wherein the A-site contains methylamine (MA). + ), formamidin (FA) + ) or cesium (Cs) + At least one of the cations; the B site contains tin (Sn). 2+ ) or lead (Pb 2+ At least one of the metal cations; the X-position contains iodine (I - ), chlorine (Cl) - ) or bromine (Br - At least one of the halogen anions.

5. A high-quality tin-based perovskite thin film based on guanidine-based additives, characterized in that, The perovskite film is prepared by the preparation method according to any one of claims 1-4, and the thickness of the perovskite film is 10-500 nm.

6. A field-effect transistor comprising a semiconductor layer, characterized in that, The semiconductor layer is composed of the perovskite thin film as described in claim 5.

7. The field-effect transistor according to claim 6, characterized in that, The field-effect transistor has a structure of bottom-gate top contact, bottom-gate bottom contact, top-gate bottom contact, or top-gate top contact.

8. An electronic device, characterized in that, It includes the field-effect transistor as described in claim 6 or 7.

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