Inorganic Zn2SnO4 electron transport layer in single-junction perovskite solar cells achieving highly efficient performance exceeding 32.85 %

Abstract

The performance of perovskite solar cells heavily relies on the optoelectronic characteristics of the electron transport layer (ETL). In this study, we use the first-principles methods, based on hybrid density functional theory with spin–orbit coupling, to examine the structural, electronic, and optical properties of Zn₂SnO₄ as promising candidate for the ETL in perovskite solar cells. Within the scope of structural properties, the lattice constants, bond lengths, and energy of formation are computed, showing a stable prototype structure. Our analysis of the electronic structures demonstrates that Zn₂SnO₄ has a wide direct band gap, which promotes efficient carrier extraction and correlates well with experimental measurements. Furthermore, the effective masses, dielectric constant, absorption coefficient, and exciton binding energy are studied. Additionally, we examine the photovoltaic efficiency of single-junction solar cells utilizing Zn₂SnO₄ as ETL in a standard planar device structure. The optimal cell efficiency obtained from the numerical simulation for the FTO/Zn₂SnO₄/Perovskite/Spiro-MeOTAD/Au configuration is determined to be ∼32.85 %. Furthermore, we conduct a comparative analysis of the performance of perovskite solar cell device with SnO₂ ETL. Our findings reveal that Zn₂SnO₄ exhibits superior cell efficiency compared to its SnO₂ counterpart. These results align well with previously reported experimental observations and underscore the efficacy of combining first-principles calculations with conventional device simulations for evaluating perovskite solar cell performance reliably.