Optimization of Perovskite Tandem Photovoltaic Devices for Terrestrial and Space-Based Applications Using External...

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 E_g and narrow E_g absorber layers from 350 and 975 nm to 356 and 1200 nm, the J_sc 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 (V_oc) and fill factor (FF). Under AM 0, an increase in absorber layer thickness to 310 and 1200 nm increases the J_sc 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 J_sc 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 J_sc 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.