A Lead-Free All-Inorganic CS2SnI6 Based Ultra-Thin Perovskite Solar Cell Optimized using SCAPS-1D Simulator

Abstract

In this work, an all-inorganic lead-free Cs2SnI6-based perovskite PV cell (structure FTO/TiO2/Cs2SnI6/SrCu2O2) has been optimized by varying the layer thickness, defect densities, doping profiles using SCAPS 1D simulator. A synergic optimization of the device is also performed by changing materials for Electron-Transport-Layer (ETL) and Hole-Transport-Layer (HTL) to investigate the role of device interface on the carrier dynamics. In our proposed cell structure the light illuminates through the Transparent Conducting Oxide (TCO) layer of Fluorine doped Tin Oxide (Sn2O:F), which acts as the window layer. The p-type Perovskite (Cs2SnI6) is chosen as the key absorber layer for its distinct properties. Finally, before the back-contact, SrCu2O2 as HTL is included for abrupt separation of hole from absorber owing to its greater hole conductivity with suitable offsets of valance and conduction band distribution. Moreover, SrCu2O2 based device shows enhanced efficiency than commonly used Spiro-OMeTAD based devices. According to our simulation outcomes, the optimized structure offers an overall power conversion efficiency (PCE) of 32.72%, open-circuit voltage (Voc) of 1.012 V, short-circuit current density (Jsc) of 36.7 mA/cm2 and Fill-Factor (FF) of 88.15%. The entire thickness of our optimized proposed cell is realized only 360 nm, which is extremely thin and would be very cost effective.