Numerical insights into MXene-integrated perovskite solar cells with compositionally engineered CsSnI3-xBrx absorbers

Abstract

All-inorganic perovskite solar cells (PSCs) offer superior stability compared to their hybrid counterparts, making them a promising candidate for high-performance photovoltaics. This study enhances photovoltaic (PV) performance by employing a linearly graded CsSnI_3-xBr_x absorber layer (x = 0 to 3) while eliminating toxic lead. The proposed design incorporates 2D MXene electrodes, improving charge transport without the need for electron/hole transport (ETL/HTL) layers. In this work, the distinct 21 MXenes with different termination functions are incorporated and their compatibility has been verified with CsSnI_3-xBr_x. The simulation has been performed in SCAPS-1D, under one sun illumination at 300 K temperature. The results indicated that using MXene with work function values ranging from 3.56 eV to 4.50 eV for the top electrode and from 5.36 eV to 5.65 eV for the bottom electrode resulted in the highest power conversion efficiency (PCE) of 24.18 %. Further optimization of absorber thickness, bulk defects, and acceptor doping density leads to an enhanced PCE of 29.30 % at 1000 nm thickness and a bulk defect density of 10¹² cm⁻³, with a corresponding acceptor doping density of 10¹⁵ cm⁻³. Additionally, a transparency analysis of the top electrode has been performed to evaluate its impact on PV performance. This ETL-/HTL-free, highly conductive PSC design paves the way for future advancements in next-generation photovoltaics.