Improving optoelectronic and solar cell performance from 24 to 31 % via switching from 0D Cs3Bi2I9 to 2D Cs3Bi2I6Cl3 perovskite for energy harvesting application

Perovskites based on cesium still have lower PCE than conventional perovskites. An in-depth investigation of the material and its application is necessary to learn about the physical characteristics, efficiency, and operating principle of Cs base perovskites. The toxicity of lead is another reason how lead-free perovskites are made, despite their cheap cost and incredible efficiency. Therefore WIEN2k and SCAPS-1D tools are employed to explore the structural, opto-electronic properties and solar cell efficiency of the 2D Cs₃Bi₂I₆Cl₃ perovskite. The structural properties are aligned with experiments. The electronic properties reveals its direct bandgap (2.05 eV) semiconducting nature. The optical properties reveals its visible light active nature make them ideal for optoelectronic and Solar Cell applications. The optimized FTO/PBCM-SnS₂/Cs₃Bi₂I₆Cl₃/NiO/Ni devise achieves the J_sc of 23.35 mA/cm², V_oc values of 1.47 V, FF of 90.97 and PCE of 31.27 % respectively. The outcomes revels that the 2D Cs₃Bi₂I₆Cl₃ (η = 31.27 %) is more efficient then the 0D Cs₃Bi₂I₉ (η = 24.91 %) which facilitates the future studies aimed to develop fully inorganic lead free perovskite halides to improve photovoltaic performance.