Simulation and Optimization of a Lead-Free CS2TiBr6 Perovskite solar cell structure

Abstract

In this work, we have simulated and optimized a solar cell based on the lead-free Perovskite material CS2TiBr6 with 1.6 eV bandgap energy, according to the configuration FTO/TiO2/ Cs2TiBr6/Cu2O/Au. Where TiO2 represents the electron transport layer ETL while Cu2O represents the hole transport layer HTL. The simulation model used in our study describing the calculation of the J-V characteristic, takes into account charge carrier processes and the impact of recombination at the front and back interfaces. The PV parameters were evaluated for different values of defect density at the ETL/Perovskite and Perovskite/HTL interfaces. The effect of different alternative ETL and HTL layers has been studied. The results obtained allowed to optimize the best configuration, taking into account the bandgap offsets at front and back interfaces in order to obtain the best efficiency and performance. Finally, after observing their effect, the thicknesses of the active, ETL and HTL layers were adjusted. This study allowed us to reach a conversion efficiency of 13.9% using the following architecture device SnO2 and NiO as ETL and HTL in the structure with thicknesses of 50 nm and 150 nm respectively and 1.5 μm optimized thickness for the active layer. The aim of this study is to develop a non-toxic Perovskite cell that could be used as a top part of a tandem device.