Optimization of lead-free all-inorganic two-dimensional Cs3Sb2I9 based perovskite solar cell utilizing diverse charge transport layers and its temperature-dependent performance

Although the stability issue of the traditional three-dimensional organic-inorganic hybrid perovskite solar cells can be solved through the adoption of two-dimensional and/or all-inorganic perovskite solar cells, the development of sustainable alternatives to Pb-based perovskite absorber layers has to be prioritized. Therefore, in this work, we have investigated the performance of a novel all-inorganic solar cell with a unique lead-free two-dimensional perovskite absorber layer, Cs3Sb2I9, to reveal the underlined controlling factors and maximize its efficiency. The best-performing all-inorganic ETM-HTM pair was first chosen meticulously for this solar cell after assessing the performances of six different pairs. A greater separation between the conduction band edge of the ETM and the valence band edge of the HTM tethered better performance. Next, the solar cell was further optimized in terms of various parameters, including the thicknesses of each constituent layer, defect at the interfaces, and the work function of the metal back contact. The resulting champion cell with an architecture of FTO/SnO2/Cs3Sb2I9/NiO/Ni delivered PCE as high as 17.91%. Notably, the solar cell exhibits a minimal decline in power conversion efficiency ~ 0.06% as the temperature increases from 200 °C to 400 °C, which could enhance its suitability for practical applications, particularly in tropical regions.