Method for obtaining CsPbBr3 ferroelectric single crystal film through tensile strain induction

Abstract

The invention discloses a method for obtaining a CsPbBr3 ferroelectric single crystal film through tensile strain induction. The method comprises: applying 1.1%-9.8% tensile strain to one crystal orientation on the surface of a CsPbBr3 single crystal film with any crystal face in the thickness of 2-100 nm or simultaneously applying equal 0.68%-6.24% tensile strain to two mutually perpendicular crystal orientations on the surface of a CsPbBr3 single crystal film with three pseudo cubic crystal faces of (100) c, (010) c or (001) c; inducing the CsPbBr3 single crystal film to be converted from a high-symmetry-structure paraelectric phase to a low-symmetry-structure ferroelectric phase, and then obtaining the CsPbBr3 single crystal film with the ferroelectric property. According to the method, complex means such as element doping are avoided, the CsPbBr3 single crystal thin film with ferroelectric performance can be directly obtained at the room temperature through a simple mechanical stretching method, then the photoelectric conversion efficiency of CsPbBr3 is effectively regulated and controlled, and the light-emitting performance and the like of a CsPbBr3-based device can be further improved.

Description

technical field [0001] The invention relates to the field of ferroelectric perovskite technology, in particular to a method of obtaining CsPbBr through tensile strain induction 3 method for ferroelectric single crystal thin films. Background technique [0002] In recent years, all-inorganic halide perovskites have become a new generation of highly competitive optoelectronic functional materials due to their excellent stability and optoelectronic properties, and have been widely used in solar cells, photodetection, light-emitting diodes, LEDs and other fields. Among them, the all-inorganic perovskite CsPbBr 3 Due to its excellent high temperature and high humidity resistance, low production cost, high light absorption coefficient, high carrier mobility and high open circuit voltage, it has attracted great attention from researchers. [0003] At present, the vast majority of semiconductor and microelectronic devices can be prepared from the material Si, including N-type semi...

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Problems solved by technology

Li et al. CsPbBr 3 After cooling to 77K, it was found that its structure was an orthorhombic phase and the existence of ferroelectricity was detected. However, when the temperature reached 298K, its crystal structure returned to a cubic structure, which could not meet the needs of room temperature and higher temperatures (Xia Li, et al. Evidence for Ferroelectricity of All-Inorganic Perovskite CsPbBr 3 Quantum Dots, Journal of the American Chemical Society, 2020, 142(7):3316-3320)

Zhao and his team through the tetragonal perovskite CsPbBr 3 Applying hydrostatic pressure from 0GPa to 19GPa optimizes the crystal geometry and obtains strong ferroelectricity. However, the method of applying stress is relatively complicated, and the equipment required for the experiment requires high precision (Yu-Qing Zhao, et al. Pressure -Induced Strong Ferroelectric Polarization in Tetra-PhasePerovskite CsPbBr 3 ,Physical Chemistry Chemical Physics,2018,20(21):14718-14724)

Lu et al. combined in-situ preparation with controllable mechanical stretching, and prepared a polymer composite film with strong emission polarization photoluminescence by embedding perovskite nanocrystals. However, the preparation process is cumbersome and stretching The object needs to be further expanded, and the research on its ferroelectric properties has not yet been involved (Wen-Gao Lu, et al. Strong Polarized Photoluminescence from Stretched Perovskite-Nanocrystal-Embedded Polymer Composite Films, Advanced Optical Materials, 2017,5(23):1700594)

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