Optimizing lead-free CH3NH3SnI3 perovskite solar cells by using SCAPS-1D software

Abstract

The lead-free CH₃NH₃SnI₃ perovskite is essential for absorbing light in perovskite solar cells (PSCs). In a photovoltaic (PV) device setup of FTO/STO/CH₃NH₃SnI₃/Spiro-OMeTAD/Au, it demonstrates excellent PV performance. This device includes sulfur-doped tin oxide (STO) for the layer of electron transport (ETL), CH₃NH₃SnI₃ as the absorber, and the hole transport layer (HTL) is Spiro-OMeTAD. The upper and back contacts consist of fluorine-doped tin oxide (FTO) and gold (Au), connecting these layers. Several parameters were estimated using the Solar Cell Capacitance Simulator (SCAPS-1D) program, including the thickness, acceptor and donor densities, series and shunt resistances, and temperature. The absorber, HTL, ETL, and FTO thicknesses were set at 1000 ​nm, 100 ​nm, 150 ​nm, and 50 ​nm, respectively, to find the perfect configuration. Densities of acceptors and donors were maintained at 10¹⁹ ​cm⁻³, 2.0 ​× ​10¹⁹ ​cm⁻³, 2.0 ​× ​10¹⁸ ​cm⁻³, and 10¹⁸ ​cm⁻³ for the absorber, HTL, ETL, and FTO, respectively, at an operating temperature of 300K. The device configuration exhibited reduced series resistance and increased shunt resistance, optimized with a back contact metal of Au. The idealized model demonstrated significant PV execution characteristics, including 1.117 ​V for open-circuit voltage (V_OC), 28.88 ​mA/cm² for short-circuit current density (J_SC), 88.47 ​% for fill factor (FF), and 28.55 ​% for power conversion efficiency (PCE) under the AM1.5G spectrum. Additionally, the device displayed an average quantum efficiency (QE) of approximately 88.30 ​% at visible light wavelengths.