Panchromatic thin perovskite solar cells with broadband plasmonic absorption enhancement and efficient light scattering management by Au@Ag core-shell nanocuboids

Enhancing the low-energy sunlight harvesting is of great importance for improving the efficiency of organic-inorganic halide perovskite solar cells (PSCs) but still remains a big challenge. Herein, we propose an improved light harvesting and management strategy by using rationally-designed Au@Ag core-shell nanocuboids as plasmonic inclusions, aiming at achieving panchromatic thin PSCs. Compared to conventional metal nanostructures with a single narrow plasmon resonance band, the Au@Ag nanocuboids exhibit multiple broader and stronger plasmon resonances that can be tuned by adjusting structural dimensions to spectrally match the absorption band of the perovskite, particularly in its weak absorption region. By carefully tailoring the location of the Au@Ag nanocuboids in the electrodes, both plasmonic near-field enhancement and increased light-scattering effects can be fully exploited to boost up the performance of the PSCs. As a result, the hybrid devices demonstrate high photon-to-electron conversion efficiency (IPCE) over the entire visible range, with a remarkable IPCE enhancement (ΔIPCE/IPCE) of 20–60% in the range of 550–750 nm, compared with pristine devices. This also leads to an average power conversion efficiency (PCE) of 17.83% for the optimized Au@Ag incorporated cells, with a champion PCE of 18.31% recorded for the best plasmonic PSC, corresponding to a PCE enhancement of 20.8%.