Abstract
In this study, Ag@SiO&sub2; nanoparticles were synthesized by a modified Stöber method for preparing the TiO&sub2; mesoporous layer of carbon counter electrode-based perovskite solar cells (PSCs) without a hole transporting layer. Compared with normal PSCs (without Ag@SiO&sub2; incorporated in the TiO&sub2; mesoporous layer), PSCs with an optimal content of Ag@SiO&sub2; (0.3 wt. % Ag@SiO&sub2;-TiO&sub2;) show a 19.46% increase in their power conversion efficiency, from 12.23% to 14.61%, which is mainly attributed to the 13.89% enhancement of the short-circuit current density, from 20.23 mA/cm² to 23.04 mA/cm². These enhancements mainly contributed to the localized surface Plasmon resonance effect and the strong scattering effect of Ag@SiO&sub2; nanoparticles. However, increasing the Ag@SiO&sub2; concentration in the mesoporous layer past the optimum level cannot further increase the short-circuit current density and incident photon-to-electron conversion efficiency of the devices, which is primarily ascribed to the electron transport pathways being impeded by the insulating silica shells inside the TiO&sub2; network.