Investigation of photovoltaic performance of lead-free CsSnI3-based perovskite solar cell with different hole transport layers: First Principle Calculations and SCAPS-1D Analysis

Perovskite solar cells (PSCs) are getting maximum consideration among the research community because of the abrupt rise in their power conservation efficiency (PCE) to 25.5 % within a short span of time. However, the toxicity of the more dominating lead (Pb) based perovskites has been a major obstacle in the path of its commercialization. In this study, we have performed a systematic investigation of the photovoltaic (PV) properties of Pb- free PSCs, consisting of an excellent thermally stable Cesium Tin Iodide (CsSnI3) as an absorber layer. We have explored the impact of three common hole transport layers (HTLs) namely poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(3,4-ethylenedioxythiophene) (PEDOT: PSS) and (2,2′,7,7′-Tetrakis [N, N-di(4-methoxyphenyl) amino]-9,9′-spirobifluorene) (Spiro-OMeTAD) on the performance metrics of the PSCs. The impact of thickness variation, doping density, and defect density of the absorber layer on the PV parameters namely the short circuit current density (Jsc), open circuit voltage (Voc), PCE and Fill Factor (FF) is also examined. Our proposed device comprising of a planer p-n heterojunction structure with p-type CsSnI3 as absorber layer (FTO/n-TiO2/p-CsSnI3/p-HTL) is simulated using SCAPS-1D. WIEN2K software is used to calculate the electrical and optical characteristics of the absorber layer. We found that the P3HT-based device (FTO/n-TiO2/p-CsSnI3/p-P3HT) shows the highest PCE of 26.40 % with FF of 78.21 %, Voc of 0.972 V, and Jsc of 34.70 mA/cm2. The outcomes and interpretation of this paper show that the possibility of achieving a high PCE perovskite device can be attained utilizing safe, and non-toxic materials like CsSnI3.