Optimization and Performance Analysis of Inorganic Lead-Free CsSnBr₃ Perovskite Solar Cells Using Diverse Electron Transport Materials

Abstract

The rapid enhancement in the power conversion efficiency of perovskite solar cells (PSCs) within a short time frame has introduced challenges related to the instability and toxicity linked with lead (Pb), impeding their progress toward commercial viability. In response, the exploration of Pb-free alternatives, such as CsSnBr 3 , has garnered substantial research attention. CsSnBr 3 stands out as a highly promising contender for fulfilling the role of an absorber layer in solar cell technology, distinguished by its economical nature, robust stability, and impressive efficiency. In this study, CsSnBr 3 is employed as an absorber layer, Cu 2 O as the hole transport layer (HTL), and TiO 2 , PCBM, WS 2 , ZnO, SnO 2 , and IGZO as electron transport layers (ETLs). This work focuses on enhancing the photovoltaic (PV) performance parameters of CsSnBr 3 -based PSCs using SCAPS-1D numerical simulation. This is achieved by optimizing characteristics (thickness, doping, and defect density) of the light absorber layer, ETLs, and HTL. Additionally, the effects of doping and defect density (N t ) on the PV performance at CsSnBr 3 /ETL and HTL/CsSnBr 3 interfaces are investigated. The device architecture's performance was significantly influenced by the absorber layer's thickness, acceptor density, defect density, and the combination of various ETLs and HTLs. Optimized devices employing TiO 2 , PCBM, WS 2 , ZnO, SnO 2 , and IGZO ETLs exhibited PCEs of 21.64, 21.94, 22.43, 21.94, 21.94, and 21.88%, respectively. Moreover, the study included the illustration of capacitance effects and Mott−Schottky (M−S) analysis for the six optimized devices, complemented by the computation of corresponding J−V and QE characteristics. The PV performance obtained from this thorough analysis is then compared with previously published theoretical and experimental results for CsSnBr 3based PSCs. The performance of the top six devices is validated and compared using the wxAMPS simulation tool. By employing a variety of analytical techniques and theoretical simulations, an optimized configuration is developed, leading to the achievement of the highest reported efficiency to date at 22.43% using any simulation method for indium-doped tin oxide/TiO 2 /CsSnBr 3 /Cu 2 O/Au configuration.

Theoretical Study and Analysis of CsSnX3 (X = Cl, Br, I) All-Inorganic Perovskite Solar Cells with Different X-Site Elements

“…For instance, refining the preparation process can effectively enhance the crystalline quality and photoelectric characteristics of CsSnX 3 all-inorganic perovskite films, promoting the development of all-inorganic perovskite devices. In addition, doping appropriate ions or molecules, such as Pb, Bi, N, etc., can also regulate the energy level structure and carrier transport properties of CsSnX 3 perovskites to further improve the performance of the device [ 7 ]. Xu’s group optimized the charge extraction efficiency by adding intermediate energy levels, thus obtaining a CsSnBr 3 all-inorganic perovskite device with a PCE of 9.13%, and it showed ultra-high stability at 80 °C for more than 720 h [ 8 ].…”