Department of Physics, University of Rajasthan, Jaipur, 302004, Rajasthan, India.
Environ Sci Pollut Res Int. 2023 Sep;30(44):98796-98804. doi: 10.1007/s11356-023-26890-w. Epub 2023 Apr 20.
The lead (Pb)-based halide perovskites have been reported to be promising materials for photovoltaic applications; however, the presence of toxic lead in them concerns the environmental and health issues. In this work, we have, therefore, studied the lead-free and non-toxic tin-based halide perovskite, CsSnI, which is an eco-friendly material with high power conversion efficiency, thus, being a potential candidate for photovoltaic applications. We have investigated the influence of CsI and SnI-terminated (001) surfaces on structural, electronic and optical properties of lead-free tin-based halide perovskite CsSnI from the first principal calculations, based on density functional theory (DFT). The calculations of electronic and optical parameters are performed under the parameterisation of PBE_Sol for exchange-correlation functions conjugated with modified- Beche-Johnshon (mBJ) exchange potential. The optimised lattice constant, the energy band structure and the density of states (DOS) have been calculated for the bulk and different terminated surface structures. The optical properties of CsSnI are computed in terms of the real and imaginary part of absorption coefficient, dielectric function, refractive index, conductivity, reflectivity, extinction coefficient and electron energy loss. The photovoltaic characteristics for the CsI-termination are found to be better than the bulk and SnI-terminated surfaces. This study reveals that optical and electronic properties can be tuned by selecting proper surface termination in halide perovskite CsSnI. The CsSnI surfaces exhibit semiconductor behaviour with a direct energy band gap and a high value of absorption power in the ultraviolet and visible region, rendering these inorganic halide perovskite materials important for the eco-friendly and efficient optoelectronic devices.
基于铅的卤化物钙钛矿已被报道为有前途的光伏应用材料；然而，其中存在的有毒铅引起了人们对环境和健康问题的关注。在这项工作中，我们研究了无铅无毒的锡基卤化物钙钛矿 CsSnI，它是一种环保材料，具有高效率的功率转换，因此是光伏应用的潜在候选材料。我们基于密度泛函理论（DFT），从第一性原理计算出发，研究了 CsI 和 SnI 终止（001）表面对无铅锡基卤化物钙钛矿 CsSnI 的结构、电子和光学性质的影响。电子和光学参数的计算是在交换相关函数与修正的 Beche-Johnshon（mBJ）交换势共轭的 PBE_Sol 参数化下进行的。我们计算了体相和不同终止表面结构的晶格常数、能带结构和态密度（DOS）。我们还从吸收系数、介电函数、折射率、电导率、反射率、消光系数和电子能量损失的实部和虚部来计算 CsSnI 的光学性质。我们发现，CsI 终止的光伏特性优于体相和 SnI 终止的表面。这项研究表明，可以通过选择适当的卤化物钙钛矿 CsSnI 表面终止来调整光学和电子性质。CsSnI 表面表现出半导体行为，具有直接的能带隙和在紫外和可见光区的高吸收功率值，这使得这些无机卤化物钙钛矿材料在环保和高效的光电设备中具有重要意义。
