Efficiency enhancement of triple absorber layer perovskite solar cells with the best materials for electron and hole transport layers: numerical study

In this paper, a novel perovskite solar cell (PSC) with a triple absorber layer is numerically simulated using Solar Cell Capacitance One-Dimensional software. The initial simulation of the structure (FTO/TiO2/CsSnI3/CsSnGeI3/Cs3Sb2Br9/spiro-OMeTAD/Au) reveals that by combining cesium tin triiodide (CsSnI3), cesium tin-germanium triiodide (CsSnGeI3) and cesium antimony bromide (Cs3Sb2Br9) as triple absorber layer, we obtain a higher efficiency (31.81%) than the single (CsSnI3), and double (CsSnI3/CsSnGeI3) layer structures, whose efficiencies are 12.87% and 29.41%, respectively. Then, to optimize the proposed structure, different parameters like; thicknesses of the triple absorber layer, different materials of electron transport layer (ETL) and hole transport layer (HTL), thicknesses of ETL and HTL, as well as the operating temperature have been investigated. The optimized structure (0.4/0.1/0.1 mu m of CsSnI3/CsSnGeI3/Cs3Sb2Br9 as triple absorber layer; 0.1 mu m of tungsten trioxide WO3 as ETL and 0.35 mu m of copper(I) oxide Cu2O as HTL, as well as an optimum temperature of 300 K) shows a remarkable photovoltaic parameters i.e. J (SC) = 32.640 774 mA cm(-2), V (OC)= 1.2442 V, FF = 89.17% and eta = 36.21% (which corresponds to an improvement of 4.4% compared to the initial proposed structure (31.81%)). This study's simulation results open a better route toward fabricating highly efficient PSCs.