Organic-inorganic hybrid perovskite single crystal and preparation method and application thereof
By preparing organic-inorganic hybrid perovskite single crystals, combined with 1-butyl-3-methylimidazolium heptanofluorobutyrate and an ultra-slow programmed cooling process, the stability and carrier transport problems of traditional two-dimensional perovskite materials were solved, achieving high-quality photodetectors with high reliability and fast response.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHANGSHA SEMICON TECH & APPL INNOVATION RES INST
- Filing Date
- 2026-02-12
- Publication Date
- 2026-04-14
AI Technical Summary
Existing three-dimensional perovskite materials in photodetectors exhibit high ion mobility, high bulk defect density, and sensitivity to humidity and oxygen, resulting in high dark current noise, limited response speed, and poor stability, making it difficult to meet the needs of practical applications.
By using organic-inorganic hybrid perovskite single crystals, and by introducing 1-butyl-3-methylimidazolium heptanofluorobutyrate and an ultra-slow programmed cooling process, a strong hydrogen bond network is formed, which enhances the crystal structure stability and optimizes carrier transport, thus preparing high-quality, large-size single crystals.
The stability and responsivity of high-performance photodetectors have been improved simultaneously. The device exhibits an extremely high light-dark-current on/off ratio, fast response, and long-term stability, making it suitable for signal detection in complex environments.
Smart Images
Figure CN121853178A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of perovskite materials technology, and in particular to an organic-inorganic hybrid perovskite single crystal, its preparation method, and its application. Background Technology
[0002] Photodetectors, as the core components for converting optical signals into electrical signals, have wide applications in imaging, communication, and sensing. Organic-inorganic hybrid perovskite materials are considered ideal candidate materials for next-generation high-performance photodetectors due to their excellent light absorption coefficient, tunable bandgap, and outstanding carrier transport properties. Currently, research focuses primarily on three-dimensional perovskite or polycrystalline thin films. However, the inherent high ion mobility, high bulk defect density, and sensitivity to humidity, oxygen, and light in these materials lead to problems such as high dark current noise, limited response speed, and poor long-term stability, making it difficult to meet the comprehensive requirements of reliability, sensitivity, and durability in practical applications.
[0003] To improve stability, researchers have turned their attention to Ruddlesden-Popper (RP) type two-dimensional layered perovskites. Their structure separates inorganic layers through organic cation layers, effectively suppressing the intrusion of moisture and oxygen. Furthermore, the single-crystal morphology eliminates grain boundaries, significantly reducing defect density. However, in traditional RP type two-dimensional perovskites, the organic spacer layers are mainly connected by weak van der Waals forces. This weak interlayer interaction leads to two fundamental bottlenecks: (1) insufficient mechanical and structural stability, making them prone to interlayer slippage or degradation under thermal stress or long-term operating conditions; (2) the weak van der Waals gaps severely hinder carrier transport along the interlayer direction, resulting in low carrier mobility and high recombination rate, limiting further improvements in device responsivity and response speed. In addition, to fully realize the potential of two-dimensional perovskite single crystals, high-quality, large-size, low-defect single crystals must be obtained. Traditional methods such as cooling crystallization are often limited in their effectiveness in controlling nucleation, suppressing parasitic growth, and passivating crystal defects. It is difficult to controllably prepare single-crystal materials with both excellent crystal quality and suitable morphology, which has become another key process bottleneck restricting the realization of high-performance devices.
[0004] Therefore, there is an urgent need in this field for an innovative material design and preparation scheme that can fundamentally strengthen the interlayer coupling of two-dimensional perovskites to simultaneously improve their structural stability and carrier transport capability, and develop a repeatable and efficient process for preparing high-quality single crystals, thereby providing a reliable material basis for constructing a new generation of perovskite photodetectors that combine high sensitivity, fast response, and high stability. Summary of the Invention
[0005] In view of the above-mentioned problems, this invention provides an organic-inorganic hybrid perovskite single crystal, its preparation method, and its applications. The two-dimensional organic-inorganic hybrid perovskite single crystal based on bifunctional organic molecules of this invention has significant advantages in crystal quality, photoelectric performance, and environmental stability. The innovative introduction of 1-butyl-3-methylimidazolium heptanofluorobutyrate into the preparation process, combined with an ultra-slow programmed cooling process, successfully achieves the controllable preparation of high-quality two-dimensional perovskite single crystals, providing a reliable material basis for the development of high-performance, highly stable photodetectors.
[0006] To address the aforementioned problems, this invention provides an organic-inorganic hybrid perovskite single crystal with the general structural formulas: (HOOC-R-NH4)2AX4 and (HOOC-R-NH4)4BB. 1 X8 or (HOOC-R-NH4)4CX8; Where A is Pb 2+ Sn 2+ 、Ge 2+ or Mn 2+ B is Ag + Na + or K + B 1 For In 3+ Fe 3+ Al 3+ Sb 3+ Bi 3+ Ga 3+ or Tl 3+ C is Sn 4+ 、Ge 4+ Ti 4+ or Zr 4+ X is Cl - ,Br - I - or SCN - R is C1-C 12 alkylene, phenylene, arylene or their substituted derivatives; HOOC-R-NH4 in the organic-inorganic hybrid perovskite single crystal + As an organic spacer cation, its carboxyl groups form a hydrogen bond network between crystal layers.
[0007] Preferably, R comprises a benzene ring, with a carboxyl group and an amino group separated by at least one carbon atom and connected at the meta or para position of the benzene ring.
[0008] Based on the same inventive concept, the present invention also provides a method for preparing any of the above-described organic-inorganic hybrid perovskite single crystals, comprising the following steps: S1: An aminocarboxylic acid compound with the general structural formula HOOC-R-NH3 as an organic precursor, a corresponding metal salt as a metal source, hydrogen halide HX, hypophosphorous acid, and 1-butyl-3-methylimidazolium heptanofluorobutyrate are mixed to obtain a precursor mixture; wherein the metal salt is used to provide metal cations A, B, or C as defined above. S2: Heat and stir the precursor mixture until it is completely dissolved to obtain a clear perovskite precursor solution; S3: The perovskite precursor solution is subjected to programmed cooling crystallization in a closed environment to precipitate and grow the two-dimensional organic-inorganic hybrid perovskite single crystal.
[0009] Preferably, in step S1, the metal salt is used to provide the divalent metal cation A as defined above; the metal salt is an acetate, halide salt, inorganic acid salt, or organic carboxylic acid salt; the hydrohalic acid HX is hydroiodic acid, hydrobromic acid, or hydrochloric acid; and the molar ratio of the aminocarboxylic acid compound to the metal salt is 0.5:1-2:1.
[0010] Preferably, in step S1, the amount of 1-butyl-3-methylimidazolium heptafluorobutyrate added is 0.05-0.3 mmol per millimol of the aminocarboxylic acid compound.
[0011] Preferably, in step S1, the volume of hypophosphoric acid added is 1%-6% of the total volume of the hydrohalic acid HX.
[0012] Preferably, in step S2, the heating temperature is 120-160℃ and the stirring time is 2-4 hours.
[0013] Preferably, in step S3, the starting temperature of the programmed cooling is 120-160℃, and the cooling rate is 0.15-0.5℃ / hour.
[0014] Based on the same inventive concept, the present invention also provides a photodetector, including an insulating substrate, a pair of electrodes disposed on the substrate, and a photosensitive layer connected between the pair of electrodes, wherein the photosensitive layer is any of the organic-inorganic hybrid perovskite single crystals described above or an organic-inorganic hybrid perovskite single crystal prepared by any of the preparation methods described above.
[0015] Preferably, the materials of the pair of electrodes are independently selected from gold, silver or aluminum, the electrode thickness is 40-80 nm, the channel length between the electrodes is 50-150 μm, and the electrode spacing is 5-20 μm.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves a synergistic improvement in the overall performance of two-dimensional organic-inorganic hybrid perovskite materials and devices through precise molecular design and controllable preparation processes. Its beneficial effects are specifically reflected in the following three aspects: (1) In terms of material structure design, this invention innovatively selects aminocarboxylic acid compounds with the general structural formula HOOC-R-NH3 as precursors. The HOOC-R-NH4 formed in the crystal... + The organic spacer cation plays a central role: the ammonium ion (-NH3) at one end of the cation. + The inorganic layers are anchored by ionic bonds, while the carboxyl groups (-COOH) at the other end extend directionally between adjacent inorganic layers, forming a strong intermolecular hydrogen bond network. This microstructure fundamentally replaces the fragile van der Waals forces between layers in traditional Ruddlesden-Popper perovskites. It not only greatly enhances the structural rigidity of the crystal and its intrinsic barrier to humidity and oxygen, significantly improving environmental stability, but also provides an efficient channel for the inter-layer transport of charge carriers through the hydrogen bond network. This effectively overcomes the inherent bottleneck of low carrier mobility in two-dimensional materials, achieving simultaneous optimization of stability and transport efficiency from the source.
[0017] (2) In terms of crystal growth process, the improved programmed cooling method developed in this invention introduces a key additive system. Among them, 1-butyl-3-methylimidazolium heptano-fluorobutyrate is used as a growth regulator and passivator. Its anion can dynamically coordinate with metal ions, finely controlling crystallization kinetics, inhibiting defect generation and inducing preferential crystal face growth. Hypophosphoric acid is used as a stabilizer to ensure the chemical stability of the precursor solution at high temperatures. Combined with ultra-slow programmed cooling (0.15-0.5℃ / hour), this method successfully achieves precise control of the nucleation and growth process, thereby enabling the reproducible preparation of large-size, high-crystal-quality, and low-defect-density two-dimensional perovskite single crystals, providing an ideal single-crystal material platform for high-performance optoelectronic devices.
[0018] (3) In terms of overall device performance, the planar photodetector constructed based on the aforementioned high-quality single crystal fully leverages the structural and quality advantages of the material. The device exhibits an extremely high photo-dark-current on / off ratio (>10). 4 High responsivity (>1200mA / W), high specific detectivity (>4×10⁻⁶) 12 (Jones) and microsecond-level fast response time. Most importantly, thanks to the robust hydrogen bond network structure and the low-defect characteristics of single crystal, the device exhibited excellent operational stability during long-duration, multi-cycle optical pulse testing, with no significant performance degradation. This marks a breakthrough in the sensitivity, response speed, and long-term reliability of perovskite photodetectors, laying a solid foundation for their practical application in harsh environments. Attached Figure Description
[0019] Figure 1 This is an optical image of the orange-yellow blocky single crystal prepared in Example 1 of the present invention. Figure 2 This is a schematic diagram of the crystal structure of the (3-AEBA)2PbI4 two-dimensional perovskite single crystal prepared in Example 1 of the present invention; Figure 3 The switching characteristic curves of the photodetector prepared in Example 2 of this invention under different powers of 520nm laser; Figure 4 The photocurrent curves of the photodetector prepared in Example 2 of this invention under different powers of 520nm laser; Figure 5 The responsivity variation curves of the photodetector prepared in Example 2 of this invention under different powers of 520nm laser; Figure 6 The external quantum efficiency curves of the photodetector prepared in Example 2 of this invention under different powers of 520nm laser are shown. Figure 7 The detectivity variation curves of the photodetector prepared in Example 2 of this invention under different powers of 520nm laser; Figure 8 The transient photocurrent response of the photodetector prepared in Example 2 of this invention under 520nm pulsed laser irradiation is shown. Figure 9 The stability test results of the photoelectric detector prepared in Example 2 of this invention under long-term laser pulses are shown. Figure 10 This is a photograph of the crystal obtained in Comparative Example 1 of this invention without the addition of 1-butyl-3-methylimidazolium heptafluorobutyrate; Figure 11 This is a photograph of the crystal obtained by using 1-butyl-3-methylimidazolium iodide in Comparative Example 2 of the present invention. Figure 12 This is a photograph of the crystal obtained by natural cooling and crystallization in Comparative Example 3 of the present invention. Detailed Implementation
[0020] To make the present invention easier to understand, specific embodiments are described below to further illustrate the invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art; unless otherwise specified, the raw materials and reagents involved herein can be purchased commercially or obtained by known methods.
[0021] To address the problems mentioned in the background section, this invention provides an organic-inorganic hybrid perovskite single crystal, its preparation method, and its applications. The two-dimensional organic-inorganic hybrid perovskite single crystal based on bifunctional organic molecules of this invention exhibits significant advantages in crystal quality, photoelectric performance, and environmental stability. The innovative introduction of 1-butyl-3-methylimidazolium heptanofluorobutyrate into the preparation process, combined with an ultra-slow programmed cooling process, successfully achieves the controllable preparation of high-quality two-dimensional perovskite single crystals, providing a reliable material basis for the development of high-performance, highly stable photodetectors.
[0022] The following examples and comparative models further illustrate this point.
[0023] Example 1 A method for preparing an organic-inorganic hybrid perovskite single crystal includes the following steps: (1) Weigh 0.1812 g (1 mmol) of 3-(2-aminoethyl)benzoic acid, 0.3793 g (1 mmol) of lead acetate trihydrate and 0.0352 g (0.1 mmol) of 1-butyl-3-methylimidazolium heptafluorobutyrate, and transfer the weighed amount to a 20 mL pressure-resistant glass bottle that has been ultrasonically cleaned and dried in acetone, ethanol and deionized water in sequence. Use a graduated cylinder to slowly add 10 mL of 47% hydroiodic acid aqueous solution to the pressure-resistant glass bottle. Use a microsyringe to accurately add 0.6 mL of hypophosphoric acid as a crystallization stabilizer and reducing agent and mix to obtain a precursor mixture. (2) After sealing the pressure-resistant glass bottle containing the above precursor mixture, place it on a heated magnetic stirrer, set the temperature to 150℃ and the stirring speed to 500 rpm. Under these conditions, stir continuously for 2 hours until the solid substance in the bottle is observed to be completely dissolved, forming a clear, transparent, orange-yellow homogeneous solution (perovskite precursor solution). The entire dissolution process must be carried out in a fume hood, and attention should be paid to observing the color change of the solution.
[0024] (3) The above perovskite precursor solution was rapidly transferred to a preheated temperature-controlled oven at 120°C; the oven cooling program was set as follows: the temperature was slowly reduced from 120°C to room temperature at a constant rate of 0.2°C / hour; the entire cooling process lasted for about 15 days, during which the oven was kept absolutely still to avoid any form of vibration interference; after the program cooling was completed, the pressure-resistant glass bottle was carefully opened, and orange-yellow blocky single crystals with a size of about 2mm×7mm×0.5mm were visible growing at the bottom of the bottle. Figure 1 The single crystal was removed using PTFE tweezers, and the residual mother liquor on the surface was immediately blotted dry with lint-free paper. The single crystal was then placed in a vacuum drying oven and dried at 60°C for 4 hours, finally obtaining a high-quality (3-AEBA)₂PbI₄ two-dimensional perovskite single crystal.
[0025] The obtained single crystals were analyzed using a Bruker dual-microspot X-ray single-crystal diffractometer at a temperature of 150 K. The crystal structure was solved directly using Olex2 software. Figure 2 The results showed that the chemical formula of the single crystal was (HOOC-C6H4-CH2CH2NH4)2PbI4, which is composed of 3-(2-aminoethyl)benzoic acid cations and an inorganic layer [PbI6]. 4- A two-dimensional layered structure formed by alternating stacking.
[0026] Example 2 A photodetector The (3-AEBA)₂PbI₄ two-dimensional perovskite single crystal with a smooth surface and moderate thickness, prepared in Example 1, was selected. An electrode mask was placed on the mask, and metal electrodes were deposited on its surface using a thermal evaporation deposition apparatus. The electrodes were gold, with a thickness of 50 nm, a channel length of 72 μm, and an electrode spacing of 10 μm. The photoelectric properties of the device were characterized using a testing system consisting of a semiconductor parameter analyzer and a laser. The tests were conducted in an atmospheric environment at room temperature, with the relative humidity controlled at approximately 40%.
[0027] Under dark conditions and illumination of different wavelengths, scanning voltages (-3V to +3V) were applied to the device, and its current-voltage characteristic curves were measured. The test results show that the device exhibits significant photoelectric response in the visible light range of 405nm to 635nm, with the most significant response at 520nm. Furthermore, as... Figure 3 As shown, the photoelectric response characteristics of the device under different light intensities were tested at a 5V bias voltage: the current under dark conditions was 1.12 × 10⁻⁶. -11 A. At 10 μW / cm 2 Under 520nm laser irradiation, the photocurrent significantly increased to 1.2×10⁻⁶. -7 A ( Figure 4 The light-dark current switching ratio reaches 10. 4This indicates that the device has extremely low noise levels and excellent optoelectronic switching performance.
[0028] The responsiveness is expressed by the formula R=I p / (P _light Calculate using ×S), where I p For photocurrent, P _light Let be the incident light power density, and S be the effective illumination area. The external quantum efficiency (EQE) is calculated as EQE = (R × h × c) / (q × λ) × 100%, where h is Planck's constant, c is the speed of light, q is the elementary charge, and λ is the incident light wavelength. Tests and calculations were performed at different light powers, and the results are as follows: Figures 5-6 As shown. By Figure 5-6 It can be seen that under low optical power conditions, the maximum responsivity of the device reaches 1213 mA / W, and the corresponding maximum EQE is about 289%.
[0029] Detection rate is based on formula D =R×S 1 / 2 / (2×q×I _dark ) 1 / 2 The calculation results are as follows: Figure 7 As shown, the device's maximum specific detectivity reaches 4.18 × 10⁻⁶. 12 Jones.
[0030] To characterize the device's response speed, a high-frequency pulsed laser (frequency 1 kHz, wavelength 520 nm) was used to illuminate the device, and the transient response curve of the photocurrent was recorded using an oscilloscope. Figure 8 After data processing and analysis, the rise time (the time required for the photocurrent to rise from 10% to 90%) of the device was found to be 341 μs, and the fall time (the time required for the photocurrent to fall from 90% to 10%) was 305 μs. This fast response characteristic indicates that the device is suitable for dynamic optical signal detection.
[0031] Finally, the stability of the device under long-term pulsed laser irradiation was tested, and the results are as follows: Figure 9 As shown. By Figure 9 It can be seen that under 520nm pulsed laser irradiation at 0.5Hz, the device performance did not significantly degrade after 500 cycles, indicating that the photodetector of (3-AEBA)2PbI4 two-dimensional perovskite single crystal in this embodiment of the invention has excellent working stability.
[0032] The above test results show that the photodetector based on the (3-AEBA)2PbI4 two-dimensional perovskite single crystal prepared by the present invention exhibits excellent performance in key aspects such as on / off ratio, responsivity, detectivity, response speed and stability. It can achieve long-term and reliable signal detection in complex environments, demonstrating good practical potential and environmental adaptability.
[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that 1-butyl-3-methylimidazolium heptafluorobutyrate is not added; all other steps and parameters are the same as in Example 1. Specifically: A method for preparing an organic-inorganic hybrid perovskite single crystal includes the following steps: (1) Weigh 0.1812 g (1 mmol) of 3-(2-aminoethyl)benzoic acid and 0.3793 g (1 mmol) of lead acetate trihydrate, and transfer the weighed amount to a 20 mL pressure-resistant glass bottle that has been ultrasonically cleaned and dried in acetone, ethanol and deionized water in sequence; slowly add 10 mL of 47% hydroiodic acid aqueous solution to the pressure-resistant glass bottle using a graduated cylinder, and accurately add 0.6 mL of hypophosphoric acid as a crystallization stabilizer and reducing agent using a microsyringe and mix to obtain a precursor mixture; (2) After sealing the pressure-resistant glass bottle containing the above precursor mixture, place it on a heated magnetic stirrer, set the temperature to 150℃ and the stirring speed to 500 rpm. Under these conditions, stir continuously for 2 hours until the solid substances in the bottle are completely dissolved and a clear solution is obtained. The entire dissolution process should be carried out in a fume hood, and attention should be paid to observing the color change of the solution.
[0034] (3) Quickly transfer the above clarified solution to a preheated temperature-controlled oven at 120°C; set the oven cooling program as follows: slowly cool from 120°C to room temperature at a constant rate of 0.2°C / hour; the entire cooling process lasts approximately 15 days, during which the oven remains completely still to avoid any form of vibration interference; after the program cooling is completed, carefully open the pressure-resistant glass bottle, remove the product using PTFE tweezers, and immediately blot the surface of any residual mother liquor with lint-free paper. Then place the single crystal in a vacuum drying oven and dry at 60°C for 4 hours to obtain the product ( Figure 10 ).
[0035] Depend on Figure 10 It can be seen that the product obtained in this comparative example is a large number of small, irregular polycrystalline aggregates without obvious single crystal morphology. The crystal size is uneven and the surface is rough, making it unsuitable for preparing electrodes and devices. This indicates that the lack of coordination regulation by 1-butyl-3-methylimidazolium heptanofluorobutyrate resulted in too many nucleation sites and disordered growth during crystallization, making it impossible to form a complete single crystal. This demonstrates that the additive plays a crucial role in inhibiting random nucleation and guiding ordered growth.
[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that 1-butyl-3-methylimidazolium heptafluorobutyrate is replaced with 1-butyl-3-methylimidazolium iodide (a common ionic liquid). Other steps and parameters are the same as in Example 1. Specifically: A method for preparing an organic-inorganic hybrid perovskite single crystal includes the following steps: (1) Weigh 0.1812 g (1 mmol) of 3-(2-aminoethyl)benzoic acid, 0.3793 g (1 mmol) of lead acetate trihydrate and 0.0218 g (0.1 mmol) of 1-butyl-3-methylimidazolium iodide, and transfer the weighed amount to a 20 mL pressure-resistant glass bottle that has been ultrasonically cleaned and dried in sequence with acetone, ethanol and deionized water; slowly add 10 mL of 47% hydroiodic acid aqueous solution to the pressure-resistant glass bottle using a graduated cylinder, and accurately add 0.6 mL of hypophosphoric acid as a crystallization stabilizer and reducing agent using a microsyringe and mix to obtain a precursor mixture; (2) After sealing the pressure-resistant glass bottle containing the above precursor mixture, place it on a heated magnetic stirrer, set the temperature to 150℃ and the stirring speed to 500 rpm. Under these conditions, stir continuously for 2 hours until the solid substances in the bottle are completely dissolved and a clear solution is obtained. The entire dissolution process should be carried out in a fume hood, and attention should be paid to observing the color change of the solution.
[0037] (3) Quickly transfer the above clarified solution to a preheated temperature-controlled oven at 120°C; set the oven cooling program as follows: slowly cool from 120°C to room temperature at a constant rate of 0.2°C / hour; the entire cooling process lasts approximately 15 days, during which the oven remains completely still to avoid any form of vibration interference; after the program cooling is completed, carefully open the pressure-resistant glass bottle, remove the product using PTFE tweezers, and immediately blot the surface of any residual mother liquor with lint-free paper. Then place the single crystal in a vacuum drying oven and dry at 60°C for 4 hours to obtain the product ( Figure 11 ).
[0038] Depend on Figure 11 It can be seen that the crystals obtained in this comparative example are smaller in size, irregular in shape, and some are stacked in the form of flakes or fragments. The surface smoothness is poor, and the overall crystal quality is significantly lower than that of Example 1.
[0039] A photodetector was fabricated using the same method as in Example 2 based on the crystal described above. The dark current of this detector under a 5V bias voltage is 1.2 × 10⁻⁶. -10 A, the light-dark current switching ratio is approximately 10. 3 The responsivity is 512 mA / W, and the detectivity is 6.37 × 10⁻⁶. 11 Jones's performance was significantly lower than that of Example 2. This is because the iodide ions in 1-butyl-3-methylimidazolium iodide react with Pb. 2+ The weak coordination ability makes it impossible to effectively control crystallization kinetics and crystal face growth, resulting in more crystal defects and a decrease in carrier transport performance. This comparative example highlights the key role and irreplaceable nature of 1-butyl-3-methylimidazolium heptafluorobutyrate in the preparation method of this invention.
[0040] Comparative Example 3 The difference between this comparative example and Example 1 is that the programmed cooling crystallization in step (3) is replaced with natural cooling crystallization. Other steps and parameters are the same as in Example 1.
[0041] The above products, such as Figure 12 As shown, by Figure 12 It can be seen that a large number of grains are densely distributed in the product sample, indicating that there are many nucleation points during the crystallization process, the grain size is generally small, and the morphology is irregular with blurred edges. It is impossible to distinguish clear grain boundaries and crystal faces, indicating that the cooling rate has a decisive influence on the crystal morphology and quality.
[0042] Based on the larger particles selected from the above products, a photodetector was fabricated using the same method as in Example 2. The dark current of this detector under a 5V bias voltage was 3.8 × 10⁻⁶. -9 A, the light-dark current on / off ratio is approximately 4.7 × 10⁻⁶. 2 The responsivity is 210 mA / W, and the detectivity is 9.8 × 10⁻⁶. 10 Jones explained that natural cooling leads to rapid nucleation and disordered growth, resulting in numerous internal defects and dense grain boundaries in the crystal, which severely restricts carrier migration and collection efficiency. This further demonstrates the criticality of the ultra-slow programmed cooling process used in this invention for obtaining high-quality single crystals.
[0043] As demonstrated by the examples and comparative examples, the two-dimensional organic-inorganic hybrid perovskite single crystal based on bifunctional organic molecules of the present invention exhibits significant advantages in crystal quality, photoelectric performance, and environmental stability. Furthermore, the innovative introduction of 1-butyl-3-methylimidazolium heptanofluorobutyrate, combined with an ultra-slow programmed cooling process, successfully achieved the controllable preparation of high-quality two-dimensional perovskite single crystals, providing a reliable material foundation for the development of high-performance, highly stable photodetectors.
[0044] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. An organic-inorganic hybrid perovskite single crystal, characterized in that, Its general structural formulas are: (HOOC-R-NH4)2AX4, (HOOC-R-NH4)4BB 1 X8 or (HOOC-R-NH4)4CX8; Where A is Pb 2+ Sn 2+ 、Ge 2+ or Mn 2+ B is Ag + Na + or K + B 1 For In 3+ Fe 3+ Al 3+ Sb 3+ Bi 3+ Ga 3+ or Tl 3 + C is Sn 4+ 、Ge 4+ Ti 4+ or Zr 4+ X is Cl - ,Br - I - or SCN - R is C1-C 12 alkylene, phenylene, arylene or their substituted derivatives; HOOC-R-NH4 in the organic-inorganic hybrid perovskite single crystal + As an organic spacer cation, its carboxyl groups form a hydrogen bond network between crystal layers.
2. The organic-inorganic hybrid perovskite single crystal according to claim 1, characterized in that, The R comprises a benzene ring, with a carboxyl group and an amino group separated by at least one carbon atom and attached to the benzene ring at the meta or para position.
3. The method for preparing organic-inorganic hybrid perovskite single crystals according to claim 1 or 2, characterized in that, Includes the following steps: S1: An aminocarboxylic acid compound with the general structural formula HOOC-R-NH3 as an organic precursor, a corresponding metal salt as a metal source, hydrogen halide HX, hypophosphorous acid, and 1-butyl-3-methylimidazolium heptanofluorobutyrate are mixed to obtain a precursor mixture; wherein the metal salt is used to provide metal cations A, B, or C as defined in claim 1. S2: Heat and stir the precursor mixture until it is completely dissolved to obtain a clear perovskite precursor solution; S3: The perovskite precursor solution is subjected to programmed cooling crystallization in a closed environment to precipitate and grow the two-dimensional organic-inorganic hybrid perovskite single crystal.
4. The preparation method according to claim 3, characterized in that, In step S1, the metal salt is used to provide the divalent metal cation A as defined in claim 1; the metal salt is an acetate, halide salt, inorganic acid salt or organic carboxylic acid salt; the hydrohalic acid HX is hydroiodic acid, hydrobromic acid or hydrochloric acid; the molar ratio of the aminocarboxylic acid compound to the metal salt is 0.5:1-2:
1.
5. The preparation method according to claim 3 or 4, characterized in that, In step S1, the amount of 1-butyl-3-methylimidazolium heptafluorobutyrate added is 0.05-0.3 mmol per millimol of the aminocarboxylic acid compound.
6. The preparation method according to claim 3, characterized in that, In step S1, the volume of hypophosphoric acid added is 1%-6% of the total volume of the hydrohalic acid HX.
7. The preparation method according to claim 3, characterized in that, In step S2, the heating temperature is 120-160℃, and the stirring time is 2-4 hours.
8. The preparation method according to claim 3, characterized in that, In step S3, the starting temperature of the programmed cooling is 120-160℃, and the cooling rate is 0.15-0.5℃ / hour.
9. A photodetector, characterized in that, It includes an insulating substrate, a pair of electrodes disposed on the substrate, and a photosensitive layer connected between the pair of electrodes, wherein the photosensitive layer is an organic-inorganic hybrid perovskite single crystal as described in any one of claims 1-2 or an organic-inorganic hybrid perovskite single crystal prepared by any one of claims 3-8.
10. The photodetector according to claim 9, characterized in that, The materials of the pair of electrodes are independently selected from gold, silver or aluminum, the electrode thickness is 40-80 nm, the channel length between the electrodes is 50-150 μm, and the electrode spacing is 5-20 μm.