Method for preparing perovskite / silicon heterojunction through physical vapor deposition method and application of perovskite / silicon heterojunction

Abstract

The invention provides a method for preparing a perovskite / silicon heterojunction through a physical vapor deposition method and application of the perovskite / silicon heterojunction. Comprising the following steps: (a) synthesizing perovskite powder: completely dissolving cesium halide and lead halide in dimethyl sulfoxide according to a certain molar ratio, then adding an anti-solvent, separating out yellow precipitate, centrifuging the yellow precipitate, and carrying out vacuum drying to obtain the perovskite powder; (b) preparing a heterojunction composite material, namely preparing the heterojunction material by adopting a physical vapor deposition process, putting the obtained perovskite powder into a crucible, putting the crucible under a monocrystalline silicon substrate with a crystal phase of (100), vacuumizing, heating the crucible at a certain temperature to melt and evaporate the perovskite until the perovskite reaches the substrate above, and then, carrying out heat preservation on the substrate to obtain the heterojunction composite material. The substrate needs to be maintained at a certain temperature and rotating speed, and the compact and uniform silicon / perovskite heterojunction composite material can be obtained after a certain period of time. The composite material has excellent photoelectric properties, and has a wide application prospect in diode type photoelectric detectors.

Description

Technical Field

[0001] This invention relates to the field of heterojunction fabrication technology, specifically to a method for preparing silicon / perovskite heterojunctions by physical vapor deposition and its application. Background Technology

[0002] Perovskite materials have significant potential applications in fields such as solar cells and photodetectors due to their high light absorption coefficient, tunable band gap, and long carrier diffusion length. However, single-component perovskite materials cannot achieve ultra-high quality and complex functions in optoelectronic devices. Therefore, it is necessary to further improve the performance of optoelectronic devices by preparing perovskite heterojunction composite materials.

[0003] With the continuous development of semiconductor technology, the combination of silicon substrates and perovskite materials can further enhance the application prospects of perovskite materials. However, existing perovskite / silicon heterojunctions are constrained by the preparation process and are difficult to industrialize: during preparation, it is difficult to ensure the crystal quality and uniformity of the perovskite film. The crystallization process of perovskite materials is affected by a variety of factors, such as temperature, humidity, and solution concentration. Precisely controlling these factors over a large area is very challenging and may lead to crystallization defects, phase segregation, and other problems in the film, affecting the material performance.

[0004] Therefore, how to develop new processes to prepare silicon / perovskite heterojunction composite materials is an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a method for preparing perovskite / silicon heterojunctions by physical vapor deposition and its application, which can improve the growth of perovskite thin films on silicon surfaces and obtain high-quality perovskite / silicon heterojunction composite materials.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: A method for preparing perovskite / silicon heterojunctions by physical vapor deposition is provided, comprising the following steps: (a) Synthesis of perovskite powder: Cesium halide and lead halide are completely dissolved in dimethyl sulfoxide at a certain molar ratio, and then an antisolvent is added to precipitate the precipitate. The precipitate is centrifuged and vacuum dried to obtain perovskite powder. (b) Preparation of heterojunction composite material: The heterojunction material is prepared by physical vapor deposition. The obtained perovskite powder is placed in a crucible, which is placed directly below a single crystal silicon substrate with a crystal phase of (100). The crucible is then evacuated and heated at a certain temperature to melt and evaporate the perovskite and reach the substrate above. The substrate needs to maintain a certain temperature and rotation speed. After a certain time, the silicon / perovskite heterojunction composite material is obtained.

[0007] As a preferred option, in step (a), the molar ratio of cesium halide to lead halide is 1:(1 to 1.5).

[0008] As a preferred option, in step (a), the antisolvent is toluene, chlorobenzene, or dichloromethane.

[0009] As a preferred embodiment, in step (b), the vacuum degree is 10. -5 ~10 -3 Pa.

[0010] As a preferred option, in step (b), the crucible is heated to a temperature of 400–500°C.

[0011] As a preferred embodiment, in step (b), the substrate is maintained at a temperature of 400°C and the rotation speed is 10 r / min.

[0012] As a preferred option, the preparation time in step (b) is 5 to 10 minutes.

[0013] This application also provides an application of the perovskite / silicon heterojunction material prepared by the above-mentioned physical vapor deposition method in a diode-type photodetector.

[0014] The beneficial effects of this invention are: the perovskite / silicon heterojunction material prepared by physical vapor deposition has high uniformity; the preparation process is carried out in a low-pressure environment, which helps to form a high-quality perovskite / silicon heterojunction; growing a perovskite film on a silicon substrate, with band matching and atomic-level interface bonding between the two, can improve the efficiency of the device. Attached Figure Description

[0015] Figure 1 The image shown is a physical representation of an embodiment of the present invention. Figure 2 The X-ray diffraction pattern of the perovskite obtained in this invention is shown. Figure 3 Scanning electron microscope images from embodiments of the present invention; Figure 4 The image shown is a cross-sectional scanning electron microscope image according to an embodiment of the present invention. Figure 5 This is a schematic diagram of a diode-type photodetector made of perovskite / silicon heterojunction composite material. Figure 6 This is an IV curve of a diode-type photodetector under low light and a 532nm wavelength light source. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides a method for preparing perovskite / silicon heterojunctions by physical vapor deposition, comprising the following steps: (a) Synthesis of perovskite powder: Cesium halide and lead halide are completely dissolved in dimethyl sulfoxide at a certain molar ratio of 1:(1 to 1.5). Then, toluene, chlorobenzene or dichloromethane is added as an antisolvent to precipitate the powder. The precipitate is centrifuged and vacuum dried to obtain perovskite powder. (b) Preparation of heterojunction composite material: The heterojunction material was prepared by physical vapor deposition. The obtained perovskite powder was placed in a crucible, which was placed directly below a single-crystal silicon substrate with a crystal phase of (100). The vacuum was evacuated to 100°C. -5 ~10 -3 Pa, then the crucible is heated at 400-500℃ to melt and evaporate the perovskite, which then reaches the substrate above. The substrate needs to be maintained at 400℃ and 10r / min. After 5-10 minutes, a silicon / perovskite heterojunction composite material is obtained.

[0018] The present invention also provides an application of the perovskite / silicon heterojunction material prepared by the above-mentioned physical vapor deposition method in diode-type photodetectors.

[0019] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention. Example 1

[0020] (a) 200 mg of cesium bromide and 400 mg of lead bromide were completely dissolved in dimethyl sulfoxide, and then toluene was added. A yellow precipitate gradually precipitated. The yellow precipitate was centrifuged and vacuum dried to obtain perovskite powder. (b) The heterojunction material was prepared by physical vapor deposition. The obtained perovskite powder was placed in a crucible, which was placed directly below a single-crystal silicon substrate with a crystal phase of (100). The vacuum was evacuated to 100°C. -3 Pa, then the crucible is heated to 500℃ to melt and evaporate the perovskite, which then reaches the substrate above. The substrate needs to be maintained at 400℃ and rotated at 10r / min. After 5 minutes, the perovskite / silicon heterojunction composite material is obtained. Example 2

[0021] The conditions used in this embodiment are as follows: step (b) involves heating the crucible at a temperature of 500°C, and other conditions not mentioned are the same as in embodiment 1.

[0022] Characterization of heterojunction composite materials Figure 1 A photograph of the resulting composite material; Figure 2 The X-ray diffraction pattern of the thin film on the silicon substrate shows the diffraction peaks of cesium lead bromide perovskite, proving that the thin film grown on the silicon surface is a cesium lead bromide perovskite thin film. Figure 3 The scanning electron microscope image of the heterojunction composite material shows that the perovskite surface is dense and uniform, with no obvious gaps. Figure 4 The scanning electron microscope image of the cross-section of the heterojunction composite material proves that a dense perovskite film has been grown on the surface of the silicon substrate. In summary, the present invention successfully prepared a perovskite / silicon heterojunction composite material. Example 3

[0023] Application of the perovskite / silicon heterojunction composite materials prepared in Examples 1 and 2 in diode-type photodetectors.

[0024] The perovskite / silicon heterojunction composite materials prepared in Examples 1 and 2 were used to fabricate a simple diode-type photodetector, the device structure of which is as follows: Figure 5 As shown, the electron transport layer is C, which is processed layer by layer by thermal evaporation. 60 A mixture of PCBM and [other materials] was used. A 532nm monochromatic laser with a power of 5mW was then used as the light source. During testing, the light source was directed directly at the device surface, and the two ends of the device were connected with conductive probes, which were then connected to a semiconductor parameter tester. First, a voltage ranging from -5 to 5V was applied to the device under no-light conditions, and the dark-state current was recorded. Then, under illumination conditions, a voltage ranging from -5 to 5V was applied to the device, and the photocurrent as a function of voltage was recorded. From [the previous steps]... Figure 6 As can be seen, the device has a very sensitive visible light response, with an on / off ratio reaching 10. 4 In addition, the quantum efficiency can reach 80%, and the responsivity is 16 A / W.

[0025] The present invention has been illustrated with the above embodiments to describe the detailed process equipment and process flow of the present invention. However, the present invention is not limited to the above examples, that is, it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing perovskite / silicon heterojunctions by physical vapor deposition, characterized in that, Includes the following steps: (a) Synthesis of perovskite powder: Cesium halide and lead halide are completely dissolved in dimethyl sulfoxide at a certain molar ratio, and then an antisolvent is added to precipitate the precipitate. The precipitate is centrifuged and vacuum dried to obtain perovskite powder. (b) Preparation of heterojunction composite material: The heterojunction material is prepared by physical vapor deposition. The obtained perovskite powder is placed in a crucible, which is placed directly below a single crystal silicon substrate with a crystal phase of (100). The crucible is then evacuated and heated at a certain temperature to melt and evaporate the perovskite and reach the substrate above. The substrate needs to maintain a certain temperature and rotation speed. After a certain time, the silicon / perovskite heterojunction composite material is obtained.

2. The method for preparing perovskite / silicon heterojunctions by physical vapor deposition according to claim 1, characterized in that, In step (a), the molar ratio of cesium halide to lead halide is 1:(1 to 1.5).

3. The method for preparing perovskite / silicon heterojunctions by physical vapor deposition according to claim 1, characterized in that, In step (a), the antisolvent is toluene, chlorobenzene, or dichloromethane.

4. The method for preparing perovskite / silicon heterojunctions by physical vapor deposition according to claim 1, characterized in that, In step (b), the vacuum degree is 10. -5 ~10 -3 Pa.

5. The method for preparing perovskite / silicon heterojunctions by physical vapor deposition according to claim 1, characterized in that, In step (b), the crucible is heated to a temperature of 400–500°C.

6. The method for preparing perovskite / silicon heterojunctions by physical vapor deposition according to claim 1, characterized in that, In step (b), the substrate is maintained at a temperature of 400°C and the rotation speed is 10 r / min.

7. The method for preparing perovskite / silicon heterojunctions by physical vapor deposition according to claim 1, characterized in that, In step (b), the preparation time is 5-10 min.

8. The application of the perovskite / silicon heterojunction material prepared by physical vapor deposition according to any one of claims 1 to 6 in diode-type photodetectors.

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