Optimization of Perovskite Tandem Photovoltaic Devices for Terrestrial and Space-Based Applications Using External Quantum Efficiency Simulations

The absorber layer thicknesses of tandem photovoltaic devices containing hybrid organic–inorganic lead halide perovskite absorbers are optimized under AM 1.5 and AM 0 solar irradiance using external quantum efficiency (EQE) simulations. Using the EQE modeling approach derived from analysis of ellipsometric spectra collected from complete single-junction perovskite, all-perovskite tandem, and copper indium gallium diselenide (CIGS) thin film solar cells, structural–optical models are developed for two high-efficiency tandem solar cell configurations from their published EQE spectra. These configurations include a superstrate all-perovskite device and a substrate perovskite/CIGS device. These models serve as realistic and practical baselines for optimizing device performance under different circumstances. By increasing the thicknesses of an all-perovskite tandem superstrate device’s wide Eg and narrow Eg absorber layers from 350 and 975 nm to 356 and 1200 nm, the Jsc may be increased from 15.81 to 15.94 mA/cm2 under AM 1.5 illumination. This corresponds to a potential increase in efficiency from 25.83 to 26.05% when using reported open circuit voltage (Voc) and fill factor (FF). Under AM 0, an increase in absorber layer thickness to 310 and 1200 nm increases the Jsc from 18.56 to 19.72 mA/cm2, which corresponds to an increase in efficiency from 30.33 to 32.22%. By increasing the thickness of the perovskite layer in a perovskite/CIGS substrate device from 500 to 615 nm, the Jsc may be increased from 18.84 to 19.65 mA/cm2 assuming AM 1.5 illumination. This change would increase efficiency from 23.74 to 24.76%. Under AM 0 illumination, an increase in the perovskite thickness to 512 nm results in an increase in predicted Jsc from 23.13 to 23.34 mA/cm2. This corresponds to a predicted efficiency increase from 29.15 to 29.41%. This modeling approach provides a stable platform for practical evaluation of different superstrate and substrate design tandem solar cells with perovskite semiconductors as at least one of their absorber layers.