Читать книгу Perovskite Materials for Energy and Environmental Applications - Группа авторов - Страница 48

X position in perovskite can be replaced with elements chlorine, bromine, and iodine. There is a considerable proportion of change in bandgap when there is alternation in the element. Altering the position of X from chlorine to iodine the band gap value ranges from 3.11eV to 1.51eV. The smallest band gap of 1.51eV is obtained by tuning the position of X in CH₃NH₃PbX₃ [38].

M and X elements should be changed simultaneously so that the appropriate bandgap can be obtained. The bandgap of CH₃NH₃SnI_3−xBr can be modulated from 1.30 to 2.15 eV by substitution of Pb with tin and partially substitution of I (iodine) with Br (bromine)_x [42]. A linearity behavior is observed between bandgap and ratio of I/Br. Efficiency is achieved up to 5.23% when CH₃NH₃SnI₃ is used as a light absorber in the solar cell [42]. On optimizing iodine and bromine ratio in CH₃NH₃SnIBr₂, a way better PSC can be produced.