高压下低维有机-无机杂化钙钛矿MAPbI_(3)纳米立方块带隙调控及光学性能的研究

Pressure-induced Band Gap Engineering and Optical Properties of Low Dimensional Organic-inorganic Hybrid Perovskite MAPbI_(3) Nanocubes

低维有机-无机杂化钙钛矿材料由于其独特的光电性能而受到广泛关注。本文利用金刚石对顶砧装置对不同尺寸的CH_(3)NH_(3)PbI_(3)(MAPbI_(3))纳米立方块进行了高压研究。并探索了尺寸效应对MAPbI_(3)纳米立方块在高压下的光学性能的影响规律。高压原位紫外-可见吸收和荧光光谱结果显示,两种不同尺寸的MAPbI_(3)纳米立方块的带隙和光学性能出现了不同的变化规律。其中,小尺寸MAPbI_(3)纳米立方块,在0.25 GPa以下,带隙随着压力的增加一直减小,而对于大尺寸纳米立方块的带隙,在0.67 GPa以下,随着压力的增加持续增加。原位高压拉曼的测量和分析表明,尺寸效应与八面体[PbI_(6)]^(4-)和有机阳离子CH_(3)NH_(3)^(+)间的相互作用有关。我们的研究结果为深入了解低维有机-无机杂化钙钛矿纳米晶的带隙调控和光学特性以及结构稳定性提供了研究依据,为提高有机-无机杂化钙钛矿电池的转化效率开辟了一种研究思路。

Low-dimensional organic-inorganic hybrid perovskite materials have attracted extensive attention due to their exotic photoelectric performance.In this paper,different size(CH_(3)NH_(3)PbI_(3))MAPbI_(3)nanocubes were studied by using diamond anvil cell(DAC),under high-pressure conditions.And explored the regulation of the size effect on the the optical properties of MAPbI_(3) nanocubes under high pressure.The in-situ high-pressure UV-visible absorption and photoluminescence spectra showed that the band gap and optical properties of MAPbI_(3) nanocubes with two different sizes showed different changes.The band gap of small-sized MAPbI_(3) nanocubes decreases with the increase of pressure below 0.25 GPa,while for large-sized nanocubes,the band gap continues to increased with the increasing of pressure below 0.67 GPa.The in-situ high pressure Raman measurement and analysis showed that the size effect was related to the interaction between the octahedron[PbI_(6)]^(4-)and the organic cation CH_(3)NH_(3)^(+).The results provide a research basis for in-depth understanding the band gap regulation,optical properties and structural stability of low dimensional organic-inorganic hybrid perovskite nanocrystals,and it provides a research idea for improving the conversion efficiency of organic-inorganic hybrid perovskite cells.