Plasmon-enhanced CH₃NH₃PbI₃ perovskite solar cells using metal nanoparticle-sensitized nanorod structures

In this study, we employed metal nanoparticle-coated nanorod (NR) arrays in the light-absorbing layer of a perovskite (CH₃NH₃PbI₃) solar cell (PSC). The methodology involved embedding NRs composed of a hole transport layer (HTL) within the active layer, followed by the placement of spherical NPs along the length of the NRs from top to bottom. It leads to a substantial enhancement in both light absorption and current generation due to the surface plasmonic (SP) effects introduced by the nanoparticles (NPs). We explored how different metals and the dimensions of nanorods influence the optical properties, specifically scattering and absorption of nanoparticles used in PSCs. By comparing nanorods made from gold, silver, copper, and aluminum, and adjusting their heights, we assessed their impact on boosting light absorption within the solar cells. Through 3D simulations, the optimal NR height was determined to be 120 nm. A systematic evaluation was conducted on four different types of plasmonic nanoparticle materials. Among these, gold (Au) NPs yielded the highest J_sc, resulting in a PCE of 16.13%, which represents an approximate 15% improvement over conventional planar PSC architectures. This work demonstrates that synergistic coupling of nanorod-induced light trapping and plasmonic resonance provides an effective strategy for overcoming the intrinsic absorption limitations of thin perovskite solar cells.