Investigating of Novel Inorganic Cubic Perovskites of A3BX3 (A=Ca, Sr, B=P, As, X=I, Br) and Their Photovoltaic Performance with Efficiency over 28%

Inorganic halide perovskite-based compounds of A3BX3 have been gaining huge attention during the development of high-efficiency solar cells (SC) in recent years. This paper, investigating the physical and chemical properties could unveil its further potential to be used as absorber materials in advanced multijunction photovoltaics. The structural, optical, and electronic characterization of different compositional compounds of A3BX3 (A=Ca/Sr, B=P/As, X=I/Br) perovskites are examined thoroughly to be used as absorber in high performance photovoltaics. The DFT study reveals direct bandgaps of 1.93 (2.60) eV, 1.58 (2.14) eV, 1.96 (2.63) eV, 1.58 (2.16) eV, 1.52 (2.30) eV, 1.26 (1.94) eV, 1.53 (2.32) eV, and 1.26 (1.96) eV at Γ for the Ca3AsBr3, Ca3AsI3, Ca3PBr3, Ca3PI3, Sr3AsBr3, Sr3AsI3, Sr3PBr3, and Sr3PI3 perovskites using PBE (HSE) methods with optical absorption of (2-5)x104 (a. u.) in the optical region (< 3.2 eV). Subsequently, the potential of the A3BX3 absorber has been investigated and analyzed at varying layer thickness, defect densities, and doping concentrations with SnS2 electron transport layer (ETL) layer using FTO/SnS2/A3BX3/Ni heterostructure with current density-voltage (J-V) characteristics and corresponding quantum efficiency (QE) observation. The power conversion efficiency (PCE) of 13.52, 20.88, 13.66, 22.47, 20.83, 28.16, 20.77, and 27.32% were achieved in Ca3AsBr3, Ca3AsI3, Ca3PBr3, Ca3PI3, Sr3AsBr3, Sr3AsI3, Sr3PBr3, and Sr3PI3 absorber-based heterojunction SC. Notably, the highest PV performance revealed a PCE over 28% with a VOC of 0.913 V, JSC of 35.75 mA/cm-3, and FF of 86.26% obtained in the Sr3AsI3 absorber SCs. Thus, these detailed studies on the physical and optoelectronic properties of eight (8) different possible absorber-based configurations including their PV applications unveil the huge potential of A3BX3 (i.e., Sr3AsI3) and provide resources for the practical cell development of inorganic perovskites-based high efficiency SC over 28%.