Structure design and optimization of a novel perovskite/GeSe tandem solar cell

Owing to their exceptional power-conversion efficiency, perovskite tandem solar cells have risen to prominence as a leading contender for next-generation photovoltaic technologies. Germanium selenide (GeSe) is a two-dimensional semiconductor optical absorption material with a small bandgap energy (1.14 eV); it has an advantage over silicon as a bottom solar cell in theory. In this work, a novel perovskite/GeSe tandem solar cell architecture is proposed and systematically investigated using SCAPS-1D numerical simulation. GeSe thin films were experimentally prepared, while their optical absorption spectra were measured to validate the optical properties and parameter selection used in the simulation. In order to get the Shockley–Queisser limit efficiency, the perovskite/GeSe tandem solar cell configuration was studied comprehensively. First, the tandem cell structure was determined by choosing three kinds of perovskite materials as the top of the battery through parametric analysis of the structure. Then, touching the optimal photoelectric property by changing various parameters and doing the current marching. Results show that the post-optimized bottom GeSe solar cell can gain the maximum power-conversion efficiency of 26.93%. By comparing the battery performance of the three laminated cells, the optimal photoelectric performance of formamidinium tin iodide/GeSe was over 37.89%. This article provides a reliable and theoretically grounded design approach for enhancing the efficiency of perovskite-based tandem solar cells with integrating experimental validation of GeSe optical properties with SCAPS-1D simulation.