Design and Optimization of Inverted Perovskite Solar Cells incorporating Metal Oxide-based Transparent Conductor

Abstract

Inverted perovskite solar cells (I-PvSCs) utilizing inexpensive and stable inorganic metal oxide-based hole transporting layers can reach higher power conversion efficiencies with low hysteresis. In this study, an oxide-metal-oxide (OMO) stack is proposed as a transparent conductor (TC) for I-PvSCs with the overcoat oxide material chosen in such a way that it also acts as a hole transport material (HTL) for the device. The proposed OMO acts as both TC and HTL for the I-PvSCs device. Using optical simulations based on the transfer matrix method, the OMO stack for maximum average visible transmittance (AVT) and short-circuit current density (J_SC) is optimized. Four different OMO combinations are investigated, with NiO as a fixed overcoat oxide layer due to its hole-transporting properties. When simulated with a simultaneous variation of up to four different layers, the ZnO/Ag/NiO stack produces the highest AVT (90.24%), while TiO₂/Ag/NiO incorporated device attained a best J_SC of 23 mAcm⁻². A detailed optical study has been conducted to understand the results, including wavelength-dependent field distribution within the stack. This study presents optimized OMO designs that can effectively substitute ITO in inverted perovskite solar cells.