A cspbbr induced by tensile strain 3 ferroelectric single crystal thin film method

Abstract

The invention discloses a method for obtaining CsPbBr through tensile strain induction 3 The method of ferroelectric single crystal thin film, through the CsPbBr of any crystal plane with a thickness of 2 nm~100 nm 3 A tensile strain of 1.1%~9.8% is applied to one crystal direction of the surface of the single crystal thin film or for (100) c , (010) c or (001) c CsPbBr with Three Pseudo-cubic Facets 3 The two mutually perpendicular crystal orientations on the surface of the single crystal film simultaneously apply an equal amount of 0.68%~6.24% tensile strain, which induces the CsPbBr 3 The single crystal thin film transforms from a high-symmetry structure paraelectric phase to a low-symmetry structure ferroelectric phase, and then obtains CsPbBr with ferroelectric properties 3 single crystal film. The present invention avoids the use of complex means such as element doping, and can directly obtain CsPbBr with ferroelectric properties at room temperature through a simple mechanical stretching method 3 Single crystal thin film, and then effectively control the CsPbBr 3 The photoelectric conversion efficiency can further improve the CsPbBr 3 Luminescence and other properties of the base device.

Description

technical field [0001] The invention relates to the field of ferroelectric perovskite technology, in particular to a CsPbBr ferroelectric perovskite induced by tensile strain 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 semico...

AI Technical Summary

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 QuantumDots, 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-Phase Perovskite 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)

Images