Origin of pressure-induced band gap tuning in tin halide perovskites
Origin of pressure-induced band gap tuning in tin halide perovskites
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DOI：
10.1039/d0ma00731e
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发表时间：
2020-11-01
影响因子：
5
通讯作者：
Malavasi, Lorenzo
中科院分区：
文献类型：
--
作者：
Coduri, Mauro;Shiell, Thomas B.;Malavasi, Lorenzo
对FASnBr(3) （FA = formamidinium）的结构和光学高压研究表明，在1.4 GPa附近发生立方到正交相变，伴随着从2.4到1.6 eV的巨大带隙红移，随着压力的进一步增加，蓝移接近0.2 eV。DFT计算表明，带隙的变化与Sn-Br键长交替的变化有关，并预测在高压下这种差异会趋于均衡。将计算扩展到类似的无铅体系，提供了卤化锡钙钛矿中压力诱导带隙调谐的统一机制，这与特定结构参数的变化有关。这些结果为预测和调节金属卤化物钙钛矿在环境压力下的压力响应提供了坚实的指导。
Structural and optical high-pressure study of FASnBr(3) (FA = formamidinium) revealed a cubic to orthorhombic phase transition near 1.4 GPa accompanied by a huge band gap red-shift from 2.4 to 1.6 eV, which is followed by a blue-shift of similar to 0.2 eV upon further pressure increase. DFT calculations indicate that the variation in band gap is related to changes in Sn-Br bond length alternation, with an equalization of such difference predicted at high pressure. Extending the calculations to analogous lead-free systems provides a unifying mechanistic picture of pressure-induced band gap tuning in tin halide perovskites, which is correlated to the variation of specific structural parameters. These results represent a solid guide to predict and modulate the pressure-response of metal halide perovskites based on the knowledge of their structural properties at ambient pressure.