A Theoretical Study to Investigate the Impact of Bilayer Interfacial Modification in Perovskite Solar Cell

The interfacial defects or imperfections in the multilayer perovskite solar cells (PSCs) are detrimental for efficient and stable devices. To produce highly efficient and stable PSCs, a bilayer between the interfaces of electron‐transport material/perovskite and perovskite/hole‐transport material can be useful for suppressing recombinations at these interfaces. To passivate the interfacial defects at the perovskite/SnO 2 and perovskite/Spiro‐OMeTAD for three absorber materials (CsPbI 3 , FAPbI 3, and Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 ), a thin layer of WO 3 and poly‐bathocuproine interfacial layer is explored using solar cell capacitance simulation in 1D. The optimized device photovoltaic performances significantly improve using bilayers. The power conversion efficiency for the FAPbI 3 ‐based PSCs in bilayer configuration is more than 12% as compared to pristine, whereas open‐circuit voltage is improved by over 13%. The enhancement in device performance is attributed to the reduction of interfacial defects at both the electron transport layer/perovskite and perovskite/hole transport layer interfaces. The proposed interface modification strategy provides a novel approach for fabricating efficient perovskite devices.