Alloy-Controlled Work Function for Enhanced Charge Extraction in All-Inorganic CsPbBr₃ Perovskite Solar Cells

All-inorganic CsPbX₃ (X=I, Br) perovskite solar cells are regarded as cost-effective and stable alternatives for next-generation photovoltaics. However, sluggish charge extraction at CsPbX₃ /charge-transporting material interfaces, which arises from large interfacial energy differences, have markedly limited the further enhancement of solar cell performance. In this work, the work function (WF) of the back electrode is tuned by doping alloyed PtNi nanowires in carbon ink to promote hole extraction from CsPbBr₃ halides, while an intermediate energy by setting carbon quantum dots (CQDs) at TiO₂ /CsPbBr₃ interface bridges electron transportation. The preliminary results demonstrate that the matching WFs and intermediate energy level markedly reduce charge recombination. A power conversion efficiency of 7.17 % is achieved for the WF-tuned all-inorganic perovskite solar cell, in comparison with 6.10 % for the pristine device, and this is further increased to 7.86 % by simultaneously modifying with CQDs. The high efficiency and improved stability make WF-controlled all-inorganic perovskite solar cells promising to develop advanced photovoltaic platforms.