Oil film confinement perovskite single crystal thin film and preparation method thereof
The growth of perovskite single crystal thin films was controlled under constant temperature conditions by oil film boundary method, which solved the problems of uneven thickness and crystal defects caused by ITC space boundary method, and obtained a high-quality millimeter-level perovskite single crystal thin film, which improved the photoelectric performance.
Patent Information
- Application Number
- CN202510418156.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2025-07-04
AI Technical Summary
When preparing perovskite single crystal thin films with the existing ITC space limit method, the film thickness is uneven, the grain size distribution is wide, crystal defects are easily generated, and single crystal surface defects are easily introduced when the hard substrate is separated.
The oil film domain confinement method is adopted to form a hydrophobic oil film on the substrate and heat it to grow under constant temperature conditions to form a domain confinement space, control crystal growth, avoid direct contact of the hard substrate, and control crystal growth using constant temperature heating to obtain uniformity and stability.
The preparation of perovskite single crystal thin film with a millimeter size is achieved, with a flat surface without stepping, high single crystal quality and excellent photoelectric performance, simplifying the preparation process and reducing the single crystal nucleation rate.
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Figure CN120250158A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optoelectronic material preparation, and particularly relates to an oil film-confined perovskite single crystal thin film and a preparation method thereof. Background Art
[0002] Perovskite materials have good optical and electrical properties, and thus have broad application prospects in the fields of solar cells, photodetectors, LEDs, etc. By preparing perovskite single crystal materials into single crystal thin films, their performance can be further improved, mainly because single crystal thin films have high crystallinity and low grain boundary density, which helps to improve the photoelectric conversion efficiency and stability of devices. Therefore, the research on the preparation of perovskite single crystal thin films has become one of the hot research fields in recent years.
[0003] Since the crystal structure of perovskite materials is relatively complex and the requirements for the preparation process are also relatively high, it is not easy to prepare perovskite single crystal thin films. In recent years, with the continuous improvement of the preparation process by researchers, the success rate of preparing high-quality perovskite single crystal thin films has been greatly improved, which has further promoted the research progress of perovskite single crystal thin films.
[0004] In addition to its application in improving device performance, perovskite single crystal thin films also have important research value in the field of materials science. By preparing perovskite single crystal thin films, researchers can deeply understand their physical and chemical properties, thereby providing a basis for the performance optimization and customized design of materials. For example, by controlling the crystal growth conditions to change the structure and properties of the material, material design and preparation for specific applications can be achieved. In addition, preparing perovskite single crystal thin films is also conducive to deeply exploring basic research issues such as quantum transport, energy conversion, and photoelectric response.
[0005] In summary, the research on the preparation of perovskite single crystal thin films is of great significance for improving device performance, broadening application fields, deeply understanding material properties, and providing a basis for material design. The preparation and research of perovskite single crystal thin films are one of the important research directions in the current fields of materials science and optoelectronics, and it has broad application prospects and scientific value. Summary of the Invention
[0006] The present invention provides an oil film-confined perovskite single crystal thin film and a preparation method thereof, aiming to solve the limitations existing in the preparation of perovskite single crystal thin films by the existing ITC space confinement method. Specifically, on the one hand, the ITC space confinement method relies on temperature gradient to drive crystal growth, and the thickness of the thin film is easily affected by the temperature field and the solvent evaporation rate, resulting in uneven thickness distribution of the thin film, wide grain size distribution, and more crystal defects introduced due to temperature difference. On the other hand, the substrates used in the ITC space confinement method are mostly hard substrates such as quartz, glass, and mica to directly form a confinement space for growth. Since the hard substrate is in direct contact with the single crystal, subsequent separation of the substrate will cause defects on the surface of the single crystal.
[0007] To achieve the above object, the embodiments of the present invention provide an oil film-confined perovskite single crystal thin film and a preparation method thereof. Due to the existence of the oil film layer and the use of constant temperature heating in the oil film confinement method of the present invention, crystal growth can be controlled more uniformly, and the quantitative index can be obtained by observing under an optical microscope; moreover, the introduction of the oil film layer well protects the single crystal thin film and avoids the crystal plane defects caused by substrate separation.
[0008] The embodiments of the present invention provide a preparation method for an oil film-confined perovskite single crystal thin film, including the following steps:
[0009] S1: Pretreat the substrate;
[0010] S2: Drop and spin-coat polydimethylsiloxane on the pretreated substrate to form a hydrophobic oil film on the surface of the substrate;
[0011] S3: Dissolve methylammonium halide and lead halide in an organic solvent in proportion, stir and dissolve, and filter to obtain a precursor solution; the halogen is selected from at least one of Cl, Br, and I;
[0012] S4: Place the substrate treated in step S2 in a petri dish, and then cover it with another substrate so that the oil film layers face each other to form a confinement space;
[0013] S5: Drop the precursor solution on one side of the confinement space, and heat the petri dish in a constant temperature oil bath at 60 - 110 °C for 12 - 24 h, separate the upper substrate, and rinse and dry it with cyclohexane solution to obtain a perovskite single crystal thin film with a millimeter-sized dimension.
[0014] Preferably, the pretreatment process includes ultrasonic water bath cleaning with pure water, ethanol, acetone, and isopropanol in sequence for 20 min, and drying with a nitrogen gas gun.
[0015] Preferably, the viscosity of the polydimethylsiloxane is 100 cs.
[0016] Preferably, the spin-coating process is specifically as follows: rotate at 1000 rpm for 15 s, and then rotate at 3000 - 4000 rpm for 30 s.
[0017] Preferably, the molar ratio of the methylammonium halide to the lead halide is 0.9 - 1.3.
[0018] More preferably, the molar ratio of the methylammonium halide to the lead halide is 1.
[0019] Preferably, the organic solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide.
[0020] Preferably, the concentration of the precursor solution is 1 M.
[0021] Preferably, the substrate is glass.
[0022] Based on the general concept of an invention, an embodiment of the present invention provides an oil film-confined perovskite single crystal thin film obtained by the above preparation method.
[0023] The above solution of the present invention has the following beneficial effects:
[0024] (1) The present invention realizes low perovskite single crystal nucleation rate, regular crystal surface without steps, and high single crystal quality and other morphological characteristics by means of constant temperature growth under oil film confinement. Due to the presence of the oil film layer and the use of constant temperature heating, the crystal growth can be controlled more uniformly, and the growth interface of the single crystal thin film is more stable under constant temperature conditions, which can inhibit the generation of steps on the surface of the single crystal thin film, improve the surface flatness and morphological uniformity of the thin film, and successfully prepare a perovskite single crystal thin film with a millimeter-sized size.
[0025] (2) Compared with the ITC (inverse temperature change growth) space confinement method, the method of the present invention has the characteristics of simple preparation, low single crystal nucleation rate, regular crystal surface morphology without steps, high single crystal quality, excellent optoelectronic performance, etc., providing a new preparation method for the field of perovskite single crystal thin film preparation. Description of the Drawings
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.
[0027] Figure 1 is a physical diagram of the crystal of the perovskite single crystal thin film in the embodiment of the present invention;
[0028] Figure 2 is the morphological diagram of the perovskite single crystal thin film under an optical microscope in the embodiment of the present invention;
[0029] Figure 3 It is the crystal physical map and the morphology map under an optical microscope of the perovskite single crystal thin film of Comparative Example 1 of the present invention; (a) Crystal physical map, (b) Morphology map under an optical microscope;
[0030] Figure 4 It is the crystal physical map and the morphology map under an optical microscope of the perovskite single crystal thin film of Comparative Example 2 of the present invention; (a) Crystal physical map, (b) Morphology map under an optical microscope;
[0031] Figure 5 It is the comparison diagram of the electrical properties of the perovskite single crystal thin film device of the embodiment of the present invention and the single crystal thin film device prepared by the ITC space confinement method;
[0032] Figure 6 It is the comparison diagram of the electrical properties (current-time) of the perovskite single crystal thin film device of the embodiment of the present invention and the perovskite single crystal thin film devices of Comparative Examples 1 and 2;
[0033] Figure 7 It is the comparison diagram of the electrical properties (current-voltage) of the perovskite single crystal thin film device of the embodiment of the present invention and the perovskite single crystal thin film devices of Comparative Examples 1 and 2. Detailed implementation manners
[0034] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.
[0035] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention.
[0036] Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention can be obtained through the market or can be prepared by existing methods.
[0037] In view of the existing problems, the present invention provides an oil film-confined perovskite single crystal thin film and a preparation method thereof. The preparation method includes the following steps:
[0038] S1: Pretreat the substrate;
[0039] S2: Drop and spin-coat polydimethylsiloxane on the pretreated substrate to form a hydrophobic oil film on the substrate surface;
[0040] S3: Dissolve methylammonium halide and lead halide in an organic solvent in proportion, stir and dissolve, and filter to obtain a precursor solution; the halogen is selected from at least one of Cl, Br, and I;
[0041] S4: Place the substrate processed in step S2 in a petri dish, and then cover it with another substrate so that the oil film layers face each other to form a confined space;
[0042] S5: Drop the precursor solution on one side of the confined space, and subject the petri dish to a constant-temperature oil bath heating at 60 - 110 °C for 12 - 24 h. Separate the upper substrate and rinse and dry it with cyclohexane solution to obtain a perovskite single-crystal thin film with millimeter-scale dimensions.
[0043] Preferably, the pretreatment process includes ultrasonic water bath cleaning with pure water, ethanol, acetone, and isopropanol in sequence for 20 min, and drying with a nitrogen air gun.
[0044] Preferably, the viscosity of the polydimethylsiloxane is 100 cs.
[0045] Preferably, the spin-coating process is specifically: rotate at 1000 rpm for 15 s, and then rotate at 3000 - 4000 rpm for 30 s.
[0046] Preferably, the molar ratio of methylammonium halide to lead halide is 0.9 - 1.3.
[0047] More preferably, the molar ratio of methylammonium halide to lead halide is 1.
[0048] Preferably, the organic solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide.
[0049] Preferably, the concentration of the precursor solution is 1 M.
[0050] Preferably, the substrate is glass.
[0051] Based on the general concept of an invention, the embodiments of the present invention provide the oil film-confined perovskite single-crystal thin film obtained by the above preparation method.
[0052] The following will be described in detail through specific examples
[0053] Example 1
[0054] This example provides a method for preparing a MAPbBr3 perovskite single-crystal thin film by oil film confinement, which specifically includes the following steps:
[0055] Step 1: Ultrasonically clean the glass substrate with pure water, ethanol, acetone, and isopropanol in sequence for 20 min, and then take it out and dry it with a nitrogen air gun.
[0056] Step 2: Place the dried substrate on a spin coater, drop polydimethylsiloxane and perform spin coating to form a hydrophobic oil film on the substrate surface, and then place it in a vacuum drying oven for storage, where the spin coater rotates at a slow speed of 1000 rpm for 15 s and at a fast speed of 3000 rpm for 30 s.
[0057] Step 3: Dissolve PbBr2 powder (1.82 g) and MABr (0.56 g) in 5 mL of DMF (N,N-dimethylformamide) solution and stir at room temperature for 12 h, where the rotation speed of the magnetic stirrer is 700 rpm to obtain a clear perovskite solution, and then filter through an organic filter membrane with a pore size of 0.22 μm to obtain a precursor solution.
[0058] Step 4: Take out the glass substrate and place it in a petri dish, with the bottom oil film layer facing up and the top oil film layer facing down to cover it and leave a part of the bottom substrate outside for easy dropping of the precursor solution.
[0059] Step 5: Drop 0.3 mL of the precursor solution on the exposed part of the bottom substrate, and then heat it in an oil bath at a constant temperature of 80 °C for 12 h to obtain a MAPbBr3 single crystal thin film with a size of 3×4 mm.
[0060] Step 6: Separate the upper oil film substrate, and rinse the surface of the single crystal thin film with 1 mL of cyclohexane solution three times to remove the residual oil film on the surface, then dry the residual cyclohexane on the surface of the single crystal thin film with a nitrogen gun and place it in a vacuum drying oven at 60 °C for storage, thus obtaining.
[0061] Example 2
[0062] This example provides a method for preparing MAPbI3 perovskite single crystal thin film by oil film confinement, which specifically includes the following steps:
[0063] Step 1: Ultrasonically bath clean the glass substrate with pure water, ethanol, acetone, and isopropanol in sequence for 20 min, and then take it out and dry it with a nitrogen gun.
[0064] Step 2: Place the dried substrate on a spin coater, drop polydimethylsiloxane for spin coating to form a hydrophobic oil film on the substrate surface, and then place it in a vacuum drying oven for storage, where the spin coater rotates at a slow speed of 1000 rpm for 15 s and at a fast speed of 4000 rpm for 30 s.
[0065] Step 3: Dissolve PbI2 powder (2.35 g) and MAI (0.632 g) in 5 mL of a mixed solution of DMF and DMSO, where the volume ratio of DMF to DMSO is 9:1, and stir at room temperature for 12 h to obtain a clear solution, and then filter through an organic filter membrane with a pore size of 0.25 μm to obtain a precursor solution.
[0066] Step 4: Take out the glass substrate and place it in a petri dish, with the bottom oil film layer facing up and the top oil film layer facing down to cover it and leave a part of the bottom substrate outside for easy dropping of the precursor solution.
[0067] Step 5: Drop 0.3 mL of the precursor solution onto the exposed part of the bottom substrate. Subsequently, heat it at a constant temperature of 110 °C for 12 h, then drop another 0.3 mL of the precursor liquid, and heat it for another 12 h to obtain a MAPbI3 single crystal thin film with a size of 2×2 mm.
[0068] Step 6: Separate the upper oil film substrate, and rinse the residual oil film on the surface of the single crystal thin film 3 times with 1 mL of cyclohexane solution. Then, use a nitrogen gun to blow dry the residual cyclohexane on the surface of the single crystal thin film and place it in a vacuum drying oven at 60 °C for storage, thus obtaining it.
[0069] Comparative Example 1
[0070] The difference between this comparative example and Example 1 is that it is heated in an oil bath at a constant temperature of 80 °C for 48 h, and other operation steps and parameters are the same as those in Example 1.
[0071] Finally, a MAPbBr3 single crystal thin film with a size of 1×2 mm can be obtained. As Figure 3 shown, it can be seen that when the heating time is too long, a step morphology will be generated on the surface of the single crystal, and at the same time, the thickness of the thin film will also increase, making it difficult to obtain a single crystal thin film with regular shape and smooth surface.
[0072] Comparative Example 2
[0073] The difference between this comparative example and Example 1 is that the heating temperature in the oil bath at a constant temperature is 120 °C, and the heating duration is 12 h.
[0074] Finally, a MAPbBr3 single crystal thin film with a size of 1×3 mm can be obtained. As Figure 4 shown, it can be seen that when the heating temperature is too high, cracks and fragments will be generated on the surface of the single crystal, making it difficult to obtain a complete single crystal thin film with a smooth surface.
[0075] Application Example 1
[0076] The MAPbBr3 single crystal thin film prepared in Example 1 above and the MAPbBr3 single crystal thin film prepared by the ITC spatial confinement method are used in a vacuum coating machine to deposit electrodes of 50 nm Ag - 10 nm Au on the surface of the single crystal by vacuum thermal evaporation for electrical property testing. The results are shown in Table 1. Table 1 is a comparison of the electrical properties of the single crystal thin film prepared by the ITC spatial confinement method and the single crystal thin film prepared by the oil film confinement method of the present invention. Among them, the data are all tested under a light wavelength of 532 nm and a light power density of 0.106 mw / cm 2 below.
[0077]
[0078] Application Example 2
[0079] The electrical properties of the MAPbBr3 single crystal thin film prepared in the above Example 1 were tested with the single crystal thin films prepared in Comparative Examples 1 and 2 under different temperature and time conditions, and the results are shown in Table 2. Table 2 shows the comparison of the electrical properties of the single crystal thin films prepared under the conditions of Comparative Examples 1 and 2 with the single crystal thin film prepared in Example 1. Both of them were tested under the conditions of a light wavelength of 532 nm and a light power density of 0.112 mw / cm 2 . As can be seen from Table 2, high temperature or too long growth time will affect the crystal morphology, and further affect the electrical properties of the device.
[0080] Group Dark current (A@-3V) Photocurrent (A@-3V) Example 1 <![CDATA[4.43×10 -11 > <![CDATA[1.38×10 -6 > Comparative Example 1 <![CDATA[4.38×10 -11 > <![CDATA[8.62×10 -8 > Comparative Example 2 <![CDATA[4.63×10 -11 > <![CDATA[1.54×10 -7 >
[0081] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A preparation method of an oil film-confined perovskite single crystal thin film, characterized in that It includes the following steps: S1: Pretreat the substrate; S2: Drop and spin-coat polydimethylsiloxane on the pretreated substrate to form a hydrophobic oil film on the substrate surface; S3: Dissolve methylammonium halide and lead halide in an organic solvent in proportion, stir and dissolve, and filter to obtain a precursor solution; the halogen is selected from at least one of Cl, Br, and I; S4: Place the substrate treated in step S2 in a petri dish, and then cover it with another substrate so that the oil film layers face each other to form a confined space; S5: Drop the precursor solution on one side of the confined space, and heat the petri dish in a constant-temperature oil bath at 60-110°C for 12-24 h, separate the upper substrate, and rinse and dry it with cyclohexane solution to obtain a perovskite single-crystal film with a millimeter-scale size.
2. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, wherein The pretreatment process includes ultrasonic water bath cleaning with pure water, ethanol, acetone, and isopropanol in sequence for 20 min, and drying with a nitrogen air gun.
3. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, wherein, The viscosity of the polydimethylsiloxane is 100 cs.
4. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, wherein, The spin-coating process is specifically: rotate at 1000 rpm for 15 s, and then rotate at 3000-4000 rpm for 30 s.
5. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, wherein, The molar ratio of methylammonium halide to lead halide is 0.9-1.
3.
6. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 5, characterized in that, The molar ratio of methylammonium halide to lead halide is 1.
7. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, characterized in that, The organic solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide.
8. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, characterized in that, The concentration of the precursor solution is 1 M.
9. The preparation method of the oil film-confined perovskite single crystal thin film according to claim 1, characterized in that, The substrate is glass.
10. An oil film-confined perovskite single-crystal film obtained by the preparation method according to any one of claims 1-9.