We report systematic design and formation of plasmonic perovskite solar cells (PSCs) by integrating Au@TiO2 core-shell nanoparticles (NPs) into porous TiO2 and/or perovskite semiconductor capping layers. The plasmonic effects in the formed PSCs are examined. The most efficient configuration is obtained by incorporating Au@TiO2 NPs into both the porous TiO2 and the perovskite capping layers, which increases the power conversion efficiency (PCE) from 12.59% to 18.24%, demonstrating over 44% enhancement, compared with the reference device without the metal NPs. The PCE enhancement is mainly attributed to short-circuit current improvement. The plasmonic enhancement effects of Au@TiO2 core-shell nanosphere photovoltaic composites are explored based on the combination of UV-vis absorption spectroscopy, external quantum efficiency (EQE), photocurrent properties, and photoluminescence (PL). The addition of Au@TiO2 nanospheres increased the rate of exciton generation and the probability of exciton dissociation, enhancing charge separation/transfer, reducing the recombination rate, and facilitating carrier transport in the device. This study contributes to understanding of plasmonic effects in perovskite solar cells and also provides a promising approach for simultaneous photon energy and electron management.
Keywords: Au nanoparticles; exciton dissociation; exciton generation; near-field; perovskite solar cells; plasmon enhancement.