A Theoretical Study on Absorbers for the Intermediate Band Solar Cell from Group IV Element (Si, Ge, Sn) Doped Aggas2

Abstract

In this study, we focus on the chalcopyrite AgGaS2 as a potential host for intermediate band solar cell. To identify an ideal absorber for an IBSC, the structural stability, electronic structure, and the possibility of achieving of the large doping concentration are investigated on group IV element (Si, Ge, Sn) doped AgGaS2 using the first-principles calculations. Based on the AIMD, the doped samples exhibited strong thermodynamic stability. The calculations on electronic structures indicate that Ge and Sn doped at Ga site can form isolated and partially filled IBs in AgGaS2, whereas Si doped at Ga site cannot. In addition, the feasibility of large doping concentration is investigated, and the results show that the lowest defect formation energy is obtained for Sn doped at Ga site under Ag-poor, Ga-poor and S-rich conditions. Overall, our theoretical work suggested that Sn doped AgGaS2 is an ideal absorber for the intermediate band solar cell.

Keywords: First-principles calculations, Intermediate band solar cell, Chalcopyrite, AgGaS2