Comparative Study of Lead-free Perovskite Materials MASnI3, MASnBr3and MAGeI3to Design, Simulate and Optimize Lead Free PSC

The advancement of photovoltaic technology has certainly been revamped by lead-based perovskite solar cells (PSCs). But lead toxicity is a big hurdle in its large-scale commercial production and usage. Hence, in current work three lead-free Perovskite materials MASnI3, MASnBr3and MAGeI3has been thoroughly investigated to develop environment friendly PSCs of high efficiency and stability. The modelled device structures utilized ZnOas electron transport layer (ETL), CH3NH3SnI3, CH3NH3SnBr3 and CH3NH3GeI3 as perovskite absorption layer (PAL), Spiro-OMeTAD as hole transport layer (HTL), Indium doped tin oxide(ITO) as top electrode and Au as anode contact. Defect density in combination with different thickness of perovskite absorption layer has been investigated to obtain optimum solar cell parameters. Ata thickness of 500 nm and defect density of 1×1014cm−3of PAL, simulated Perovskite solar cell ITO/ZnO/CH3NH3SnI3/Spiro-OMeTAD/Au provided optimized solar cell parameters as PCE25.95%,Voc1.06V, Jsc31.67mA/cm2and FF77.24%, ITO/ZnO/CH3NH3SnBr3/Spiro-OMeTAD/Au provided PCE 25.01%, VOC1.02V, JSC32.41mA/cm2and FF 75.68%, ITO/ZnO/CH3NH3SnI3/Spiro-OMeTAD/Au provided PCE 19.66%, VOC1.81V, JSC14.29mA/cm2and FF 75.95%. Further, effect of interface defect density, series resistance, shunt resistance, and temperature are studied on the solar cell characteristics.It is well observed that Sn-based devices are more efficient and less stable than Ge-based devices and vice versa.