关键词: 钙钛矿, CsCu₂I₃晶体, 重结晶提纯, 坩埚下降法, 荧光光谱, 衰减时间, 变温荧光光谱

Abstract: The all-inorganic CsCu₂I₃ crystal was characterized by one-dimensional perovskite structure with orthorhombic crystal system and Cmcm space group, which was expected to be widely used in optoelectronic devices. In this paper, a transparent and high-quality CsCu₂I₃ single crystal with diameter of 1 inch (1 inch=2.54 cm) was grown by vertical Bridgman method, employing recrystallized CuI as the raw material. The phase structure and stability of the crystal were investigated by means of X-ray powder diffraction and thermogravimetric analysis. The optical and luminescence performance of the crystal was studied by means of ultraviolet-visible transmission spectroscopy, photoluminescence spectroscopy, fluorescence lifetime and fluorescence quantum yield. In addition, the variable temperature fluorescence spectra were measured at 100~250 K. The photoluminescence intensity decreases with increasing temperature due to strong electro-phonon coupling. The exciton binding energy (E_b) of the crystal is 98.12 meV. The study shows that the CsCu₂I₃ crystal exhibits good optical properties.

Key words: perovskite, CsCu₂I₃ crystal, recrystallization purification, Bridgman method, fluorescence spectrum, decay time, variable temperature fluorescence spectrum