Si-incorporated ABX3 perovskites for next-generation solar cells

Abstract

The development of lead-free perovskite materials remains a key challenge in advancing environmentally benign photovoltaic technologies. In this study, we present a comprehensive first-principles investigation of methylammonium-based halide perovskites MASiI₃ and MASi-GeI₃, aiming to evaluate their potential as efficient, non-toxic photoabsorbers. Structural stability is confirmed through calculations of formation enthalpy, Goldschmidt tolerance factor, and octahedral factor, all supporting the formation of robust three-dimensional perovskite frameworks. Electronic band structure and density of states analyses reveal direct band gaps and low effective carrier masses, indicative of strong absorption and efficient charge transport. Optical property analysis, including dielectric functions and absorption coefficients, shows pronounced absorption in the visible range, highlighting their suitability for solar energy applications. Photovoltaic performance was assessed via calculations of short-circuit current density (J_sc), open-circuit voltage (V_oc), and theoretical power conversion efficiency (PCE), with MASiI₃ and MASi-GeI₃ achieving promising PCEs of 19.56% and 18.03%, respectively. These findings suggest that the studied silicon-based hybrid perovskites are viable candidates for next-generation lead-free photovoltaic materials.