An efficient all-perovskite two terminal monolithic tandem solar cell with improved photovoltaic parameters: A theoretical prospect

Abstract

The wide photon absorption range of tandem solar cells (TSCs) allows them to deliver higher efficiencies than single-junction solar cells. The top cell with a wide bandgap absorbs the higher energy photons, while the bottom cell with a relatively low bandgap absorbs the filtered lower energy photons. However, for cheap, efficient, and long-lasting solar cells, the design must incorporate the top and bottom cell absorber layers with an appropriate band gap. In this context, this article proposes all-perovskite tandem solar cells with suitable perovskite partners as active materials in both the upper (band gap 1.68 eV) and the lower (band gap 1.16 eV) sub-cell. This research has retrieved the calibrated top cell from a previous publication, and the bottom cell has been designed, calibrated, and optimised. The filtered spectrum of the upper cell is evaluated at different perovskite thicknesses and fed to the lower cell to set up a tandem configuration. Subsequently, the current- matching technique has been used to study the tandem short-circuit current density (JSC) at different thicknesses of both sub-cells, followed by current density-voltage (J-V) curve. A total of ten tandem J-V curves are constructed and corresponding PV parameters are obtained to obtain the optimized efficiency of 33.8% with an open circuit voltage (VOC) of 2.15 V, a fill factor (FF) of 78.87% and a JSC of 20 mA.cm−2. The reported results will open the door for future development of highly efficient and low-cost monolithic two-terminal tandem devices.