A crystal carrier and a method for growing methylamine lead bromide perovskite single crystal

Abstract

The present invention discloses a crystal carrier and a method for growing a methylamine lead bromide perovskite single crystal, belonging to the field of crystal growth technology. The crystal carrier comprises a first baffle, a second baffle, and a support plate connecting the first baffle and the second baffle, wherein a connecting rod for connecting a driving source is connected to the first baffle and / or the second baffle, and the connecting rod enables the driving source to drive the crystal carrier to perform a roller-like rotational motion. The crystal carrier and the method for growing a methylamine lead bromide perovskite single crystal provided by the present invention adopt a lateral roller-like rotation method, so that the lower layer of the solution can be fully stirred, the uniformity of the entire solute can be ensured, and the problem of defects such as white lines during crystal growth can be effectively solved.

Description

Technical Field

[0001] The invention relates to a crystal carrier and a method for growing a methylamine-lead-bromide perovskite single crystal, belonging to the technical field of crystal growth. Background Art

[0002] Methylamine lead bromide (CH 3 NH 3 PbB 3 ) In recent years, perovskite crystals have become a hot topic for new optoelectronic and semiconductor materials due to their unique and excellent optical and photoelectric properties. This material has the advantages of long carrier diffusion length, high carrier mobility, low defect density and high light absorption coefficient, and has shown great potential in many fields such as solar cells, light-emitting diodes, field-effect transistors, photodetectors, memristors, lasers, etc.

[0003] Common growth methods of methylamine lead bromide perovskite single crystals include evaporation method, cooling method, anti-solvent diffusion method, inversion crystallization method, etc. Due to gravity, the solute in the crystal growth solution is bound to be unevenly distributed. It is difficult to ensure the uniform distribution of the solute in the upper and lower layers of the solution during the rotation of the crystal carrier, which leads to macroscopic defects such as white lines in the crystal growth process. Once these defects occur, the crystal will grow rapidly at the defective site, which will cause the growth of the main crystal to stagnate and fail to reach the expected size, resulting in crystal growth failure.

[0004] To this end, the present invention provides a crystal carrier and a method for growing a methylamine lead bromide perovskite single crystal. Summary of the invention

[0005] The present invention provides a crystal carrier and a method for growing a methylamine lead bromide perovskite single crystal. The present invention adopts a horizontal drum rotation method, which can fully stir the lower layer of the solution, ensure the uniformity of the entire solute, effectively solve the problem of defects such as white lines during crystal growth, and is conducive to growing high-quality, large-sized methylamine lead bromide perovskite single crystals.

[0006] In a first aspect, the present invention provides a crystal carrier, which can fully stir the lower layer of the solution by rotating the crystal carrier in a drum-like stirring manner with a transverse rotating shaft, thereby ensuring the uniformity of the solute.

[0007] A crystal carrier comprises a first baffle, a second baffle and a support plate connecting the first baffle and the second baffle, wherein the first baffle and / or the second baffle is connected to a connecting rod for connecting a driving source, and the connecting rod enables the driving source to drive the crystal carrier to perform a drum-like rotational motion, and the crystal carrier rotates in a drum-like stirring manner with a transverse rotating axis.

[0008] Optionally, a hole for embedding the end of the seed crystal is provided on the opposite side of the first baffle plate and the second baffle plate, so as to facilitate the seed crystal to be fixed between the first baffle plate and the second baffle plate. The hole may be a rectangular parallelepiped or other shapes suitable for the end of the seed crystal to extend therein.

[0009] Optionally, a fixing nut is provided on the first baffle plate and / or the second baffle plate to lock the end of the seed crystal. By rotating the fixing nut to lock the end of the seed crystal, the seed crystal can be better fixed and the stability of the seed crystal can be maintained.

[0010] Optionally, a spoiler surface is provided on the support plate, and the support plate not only serves as a frame to support the entire crystal carrier, but also plays a stirring role when the crystal carrier rotates, thereby further ensuring the uniformity of the solute.

[0011] Optionally, the cross section of the support plate is set to be triangular, so that the outer side surface of the support plate forms a spoiler surface.

[0012] Optionally, a stirring paddle is connected to the first baffle and / or the second baffle for stirring the crystal growth solution.

[0013] Optionally, the stirring paddle is arranged on the outer side of the first baffle and / or the second baffle.

[0014] In a second aspect, the present invention provides a method for growing a methylamine lead bromide perovskite single crystal, which is prepared using the crystal carrier described in any one of the schemes of the first aspect, comprising the following steps:

[0015] Fixing the seed crystal between the first baffle and the second baffle;

[0016] placing the crystal carrier in a growth tank loaded with a growth solution;

[0017] Turn on the driving source to drive the crystal carrier to perform roller-like rotational motion.

[0018] Optionally, the growth solution is obtained by dissolving methylammonium bromide and lead bromide in N,N-dimethylformamide.

[0019] Optionally, the saturation point temperature of the growth solution is 25-35°C.

[0020] Optionally, the growth solution is pumped into the growth tank through a 0.1 μm filter.

[0021] Optionally, when the crystal carrier is placed in a growth tank loaded with a growth solution, the temperature of the growth tank is adjusted to 15-25° C. to perform a supercooling treatment on the crystal growth solution.

[0022] Optionally, the supercooling treatment time is 24-48 hours.

[0023] Optionally, after supercooling the crystal growth solution, the temperature of the growth tank is adjusted to 2-5°C below the saturation point temperature, and the seed crystal is dissolved. When the seed crystal is slightly soluble and the surface is smooth, the temperature of the growth tank is increased to 3-5°C above the saturation point temperature.

[0024] Optionally, the rotation speed of the crystal carrier is 30-60r / min when it performs drum-like rotational motion. The rotation speed of the crystal carrier can be adjusted at any time according to the crystal growth state. Increasing the rotation speed can speed up the stirring of the growth solution, which is suitable for the state of faster crystal growth. Within this speed range, defects of the crystal due to excessively fast growth can also be avoided.

[0025] Optionally, when the driving source is turned on to drive the crystal carrier to perform a roller-like rotational motion, the temperature of the growth tank is increased at a heating rate of 0.1-1° C. / d.

[0026] The beneficial effects that the present invention can produce include:

[0027] 1) The crystal carrier and the methylamine lead bromide perovskite single crystal growth method provided by the present invention adopt a horizontal drum rotation method, which can fully stir the lower layer of the solution, ensure the uniformity of the entire solute, and effectively solve the problem of defects such as white lines during crystal growth;

[0028] 2) At the same time, in the traditional rotation method, once the miscellaneous crystals appear on the crystal carrier, they will contact the main crystal and cause defects in the crystal, resulting in crystal growth failure. However, in the rotation method of the present invention, even if the miscellaneous crystals appear during the growth process, they will be rotated to the bottom of the growth groove, and will not affect the growth of the main crystal located in the middle of the crystal carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a front view of the crystal carrier in Example 1 of the present invention;

[0030] Figure 2 It is a left side view of the crystal carrier in Example 1 of the present invention;

[0031] Figure 3 Schematic diagram of the methylamine lead bromide perovskite single crystal in Example 2 of the present invention.

[0032] List of parts and reference numerals:

[0033] 1-first baffle; 2-second baffle; 3-support plate; 4-stirring paddle; 5-fixing nut; 6-connecting rod; 7-seed crystal; 8-channel. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0035] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0036] Example 1

[0037] like Figure 1-2 As shown, this embodiment discloses a crystal carrier, which can be used for the rapid growth of methylamine lead bromide perovskite single crystals. The crystal carrier consists of a disc-shaped first baffle 1 and a second baffle 2; two support plates 3; four cuboid stirring paddles 4; fixing nuts 5; connecting rods 6; and rectangular channels 8. The support plate 3 is connected to the first baffle 1 and the second baffle 3 to play a supporting role. The cross section of the support plate 3 in this embodiment is triangular to form a spoiler surface, and it also plays a stirring effect when it rotates; the first baffle 1 and the second baffle 2 are used to place strip or sheet-shaped seed crystals 7, and the seed crystals 7 in this embodiment are arranged in sheet shape; the stirring paddles 4 are sequentially distributed on the upper surface of the first baffle 1 and the lower surface of the second baffle 2, and are used to stir the crystal growth solution; the connecting rod 6 is used to connect the motor (driving source) to drive the rotation of the crystal carrier; the channels 8 are respectively located on the lower surface of the first baffle 1 and the upper surface of the second baffle 2, and are used to place the seed crystals 7; the fixing nuts 5 are located at the center of the second baffle 2, and are used to keep the seed crystals 7 stable. The crystal carrier in this embodiment has a horizontal rotating axis, so that the sheet-shaped or long strip seed crystals are fixed horizontally in the middle of the crystal carrier. When the motor drives the crystal carrier to rotate, it adopts a horizontal drum-like rotation method, which can make the lower layer of the solution be fully stirred, ensuring the uniformity of the entire solute, and effectively solving the problem of defects such as white lines during the crystal growth process.

[0038] Example 2

[0039] This embodiment discloses a method for growing a methylamine lead bromide perovskite single crystal, which specifically includes the following steps:

[0040] (1) The growth raw material methylammonium bromide (CH 3 NH 3 Br) and lead bromide (PbBr 2 ) was dissolved in N,N-dimethylformamide (DMF) to obtain a crystal growth solution, and the saturation point of the crystal growth solution was measured to be 30°C;

[0041] (2) Place the flake seed crystal 7 into the hole 8 between the first baffle plate 1 and the second baffle plate 2, and rotate the fixing nut 5 to fix the seed crystal 7;

[0042] (3) The temperature of the growth tank is adjusted to 20°C, and the crystal growth solution is supercooled for 10 hours;

[0043] (4) Pumping the growth solution into the growth tank through a 0.1 μm filter;

[0044] (5) adjusting the temperature of the growth tank to 27° C. to dissolve the seed crystal 7;

[0045] (6) When the seed crystal 7 is slightly dissolved and the surface is smooth, the temperature of the growth tank is increased to 35° C.;

[0046] (7) Turn on the motor to rotate the crystal carrier in a "drum" rotation mode. The motor speed is 30 r / min. The motor drives the crystal carrier to rotate in a "forward-stop-reverse" mode;

[0047] (8) By increasing the temperature of the growth tank at a heating rate of 0.5°C / d, methylamine lead bromide perovskite single crystals can be grown. Figure 3 .

[0048] The crystal carrier and the methylamine lead bromide perovskite single crystal growth method provided by the present invention are used to rotate in a horizontal "drum" manner to solve the problem of uneven stirring in the traditional horizontal clockwise (counterclockwise) rotation. Because of gravity, the solute in the crystal growth solution must have an uneven distribution of solutes, and the solute at the bottom of the solution is much larger than the top of the solution. This requires that the crystal growth must be carried out in a rotating manner. The ordinary rotation adopts horizontal clockwise (counterclockwise) rotation. It is difficult for the crystal carrier to ensure the uniform distribution of the solute in the upper and lower layers of the solution during the rotation process, which leads to macroscopic defects such as white lines in the crystal during the growth process. The "drum" rotation method adopted by the present invention can make the lower layer of the solution fully stirred, ensure the uniformity of the entire solute, and effectively solve the generation of defects such as white lines during the crystal growth process. At the same time, in the traditional rotation method, once the miscellaneous crystals appear on the crystal carrier, the contact between the miscellaneous crystals and the main crystals will cause defects in the crystal, resulting in the failure of crystal growth. The rotation method of the present invention can rotate the miscellaneous crystals to the bottom of the growth groove even if miscellaneous crystals appear during the growth process, without affecting the growth of the main crystals. High-quality, large-sized methylamine lead bromide perovskite single crystals can be grown, and the operation is convenient and the cost is low.

[0049] The above are only several embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, using the above disclosed technical content to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A crystal carrier, characterized in that: It comprises a first baffle, a second baffle and a support plate connecting the first baffle and the second baffle, wherein a connecting rod for connecting a driving source is connected to the first baffle and / or the second baffle, and the connecting rod enables the driving source to drive the crystal carrier to perform a horizontal roller-like rotational motion; The support plate is provided with a spoiler surface; The cross section of the support plate is set to be triangular, so that the outer side of the support plate forms a spoiler surface; The crystal carrier is placed in a growth tank filled with a growth solution.

2. The crystal carrier according to claim 1, characterized in that: A hole for embedding the end of the seed crystal is formed on the opposite side of the first baffle plate and the second baffle plate.

3. The crystal carrier according to claim 2, characterized in that: The first baffle plate and / or the second baffle plate are provided with a fixing nut for locking the end of the seed crystal.

4. The crystal carrier according to claim 1, characterized in that: The first baffle plate and / or the second baffle plate is connected with a stirring paddle.

5. The crystal carrier according to claim 4, characterized in that: The stirring paddle is arranged on the outer side of the first baffle and / or the second baffle.

6. A method for growing a methylamine lead bromide perovskite single crystal, characterized in that: The method of preparing the crystal carrier according to any one of claims 1 to 5 comprises the following steps: Fixing the seed crystal between the first baffle and the second baffle; placing the crystal carrier in a growth tank loaded with a growth solution; Turn on the driving source to drive the crystal carrier to perform roller-like rotational motion.

7. The method for growing methylamine lead bromide perovskite single crystal according to claim 6, characterized in that: The growth solution is obtained by dissolving methylammonium bromide and lead bromide in N,N-dimethylformamide.

8. The method for growing methylamine lead bromide perovskite single crystal according to claim 7, characterized in that: The saturation point temperature of the growth solution is 25-35°C.

9. The method for growing methylamine lead bromide perovskite single crystal according to claim 8, characterized in that: When the crystal carrier is placed in a growth tank loaded with a growth solution, the temperature of the growth tank is adjusted to 15-25° C. to supercool the crystal growth solution.

10. The method for growing methylamine lead bromide perovskite single crystal according to claim 9, characterized in that: The supercooling treatment time is 24-48h.

11. The method for growing methylamine lead bromide perovskite single crystal according to claim 9, characterized in that: After supercooling the crystal growth solution, adjust the growth tank temperature to 2-5°C below the saturation point temperature, dissolve the seed crystal, and when the seed crystal is slightly soluble and the surface is smooth, increase the growth tank temperature to 3-5°C above the saturation point temperature.

12. The method for growing methylamine lead bromide perovskite single crystal according to claim 6, characterized in that: The crystal carrier performs drum-like rotational motion at a speed of 30-60 r / min.

13. The method for growing methylamine lead bromide perovskite single crystal according to claim 6, characterized in that: When the driving source is turned on to drive the crystal carrier to perform a roller-like rotating motion, the temperature of the growth tank is increased at a heating rate of 0.1-1°C / d.

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