Influence of absorption, energy band alignment, electric field, recombination, layer thickness, doping concentration, temperature, reflection and defect densities on MAGeI3 perovskite solar cells with Kesterite HTLs

Abstract

Over the past decade, perovskite materials have emerged as a promising absorber layer in photo voltaic (PV) cells. Germanium (Ge) based perovskite layers have attracted the attention of scientists because of its excellent photovoltaic properties and nontoxic nature. Selecting the right material for charge transport layers (CTL) can further enhance the performance and stability of the cell. Kesterite materials are chalcogenides quaternary compound with high conductivity and tunable bandgap. They have exhibited excellent performance when employed in thin film PV cells as the active material and hence emerged as an option to be used as hole transport layer (HTL) in perovskite solar cells. In this work the Ge based perovskite solar cell (PSC) of methyl ammonium germanium tri-iodide (MAGeI3) is numerically modelled with 6 kesterite quaternary compounds as HTLs and 4 oxide/sulphide materials as electron transport layers (ETL). Henceforth, a total of 24 unique structures are numerically modelled and optimized using SCAPS-1D. A systematic methodology is adopted to analyze the effect of the charge transport materials on the absorption, quantum efficiency, energy band alignment, electric field intensity, recombination rate, carrier density, thickness, doping concentration, temperature, reflection and interface defect densities of the PSC in detail. The optimization of the PSC structures enhanced the performance of the cells up to 7% more. Based on the simulation results the best performing perovskite structures were TiO2/Per/CZTS and SnO2/Per/CZTS with PCE of 24.57% and 24.87%, Jsc of 16.13 mA cm−2 and 16.32 mA cm−2, Voc of 1.730 V and 1.733 V and F.F of 88.10% and 88.101% respectively.