Design and computational investigation of PbS-based bifacial quantum dot-sensitized solar cells

Recently, numerical simulation of solar cells has drawn significant scientific interest in photovoltaics because of its potential to reduce research expenses and time before laboratory fabrication of solar cells. In this study, we investigated the performance of a solar cell with a general configuration of FTO/ETL/PbS/P3HT/Au using SCAPS-1D simulation software (version 3.3.10). Several electron transport layer (ETL) materials, including TiO₂, ZnO, tungsten disulfide (WS₂), tin (IV) oxide, and buckminsterfullerene (C₆₀), were initially tested. After optimization, WS₂ was identified as the best ETL material, exhibiting a power conversion efficiency (PCE) of 4.91 %. Subsequently, the WS₂-based device architecture was used to test various hole transport layer (HTL) materials, including organic materials like poly(3-hexylthiophene) (P3HT) and 2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD), as well as inorganic materials such as CuSCN, Cu₂O, and copper zinc tin selenide (CZTSe). Among the HTLs tested, CZTSe exhibited the highest PCE of 13.47 %. The ideal defect density for each device was maintained at 1.0 × 10¹⁴ cm⁻³. Furthermore, a bifacial version of the device, Ag/FTO/WS2/PbS/CZTSe/Au, was simulated, showing a bifacial factor (BF) for PCE of 81.74 % and a bifacial gain (BG) of 81.89 %. Based on the simulation results, we predict that the PbS-based bifacial solar cell can achieve a PCE greater than 24 %, demonstrating its potential for high-efficiency solar energy conversion. This study systematically optimized both the electron and hole transport layers in PbS-based bifacial solar cells, demonstrating the potential of WS₂ as an effective electron transport material and CZTSe as a promising hole transport material for achieving high-efficiency performance.