Fine-tuning the metallic core-shell nanostructures for plasmonic perovskite solar cells

Plasmonic nanostructures have been widely applied in various types of solar cells for improving light absorption and therefore energy conversion efficiency. In this work, we demonstrate that Au@SiO₂ core-shell nanorods with finely tuned aspect ratios are highly beneficial for the CH₃NH₃PbI₃ perovskite solar cell, with the simultaneous enhancement of solar absorption and external quantum efficiency across a broad range of wavelength, which can contribute to the increased cross-sectional scattering and spectrally absorbing energy density. Therefore, a 16.1% improvement (from 12.4% to 14.4%) of the maximal external quantum efficiency can be achieved by such structures, accompanied with a 13.5% improvement (from 20.0 to 22.7 mA/cm²) of the maximal short-circuit current density and little improvement of the open-circuit voltage and fill factor. Our findings also provide a general guideline to design solar cell structures with thinner absorber layers and improve the absorption in other poorly light-absorbing devices like lead free perovskite solar cells as well.