The halide perovskites based solar cells have been attractive due to their excellent power conversion efficiency and low cost. The structural properties of lead based cesium halide perovskites CsPbBr_3−yI_y (y = 0, 1, 2, 3) are investigated using first principles calculations based on density functional theory. The computed electronic structure profile of CsPbBr_3−yI_y (y = 0, 1, 2, 3) reveals that these materials exhibit semiconducting behavior at normal pressure. The energy gap of CsPbBr₃ is tuned by the substitution of iodine atom for bromine atom in CsPbBr₃. Also, it is found that the energy gap values of these materials decrease with increase in pressure and a semiconductor to metallic phase transition is observed at high pressure. The optical properties of these Pb-based halide perovskite compounds against the incident photon energy radiation indicate that these materials can be the effective candidates for the solar cell applications.

基于卤化钙钛矿的太阳能电池由于其出色的功率转换效率和低成本而具有吸引力。使用基于密度泛函的第一性原理计算研究了铅基卤化铯钙钛矿CsPbBr _3-y I _y（y = 0，1，2，3）的结构性能。计算出的CsPbBr _3-y I _y（y = 0，1，2，3）的电子结构轮廓表明，这些材料在常压下表现出半导体性能。通过用碘原子代替CsPbBr _3中的溴原子来调节CsPbBr ₃的能隙。而且，发现这些材料的能隙值随着压力的增加而减小，并且在高压下观察到半导体到金属的相变。这些基于Pb的卤化物钙钛矿化合物对入射光子能量辐射的光学性质表明，这些材料可以成为太阳能电池应用的有效候选材料。