Prominent Efficiency Enhancement in Perovskite Solar Cells Employing Silica-Coated Gold Nanorods

Highly efficient planar heterojunction (PHJ) perovskite solar cells (PSCs) with a structure of ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Al were fabricated by a low-temperature solution process. As employed silica-coated gold (Au@SiO2) nanorods at the interface between the hole transport layer PEDOT:PSS and the active layer CH3NH3PbI3, the average power conversion efficiency (PCE) showed over 40% enhancement, of which the average PCE was improved from 10.9% for PHJ-PSCs without Au@SiO2 to 15.6% for PHJ-PSCs with Au@SiO2, and the champion one up to 17.6% was achieved. Both experiment and simulation results proved that prominent efficiency enhancement comes from the localized surface plasmon resonance of Au@SiO2 nanorods which could improve the incident light trapping as well as improve the transport and collection of charge carrier, resulting in the enhancement in device parameters. The results suggest that metal nanorods, e.g., Au@SiO2, could be employed to fabricate high-efficiency and low-cost PHJ-PSCs.