Surface plasmonic effects on dye-sensitized solar cells by SiO2-encapsulated Ag nanoparticles

A series of dye-sensitized solar cells (DSSCs) with different amounts of silver nanoparticles (Ag NPs) coated with a SiO2 layer were prepared as core-shell Ag@SiO2 nanoparticles (Ag@SiO2 NPs). The influence of the amount of Ag@SiO2 NPs on the performance of the DSSCs was investigated. As the amount of Ag@SiO2 NPs increased, the intensity of the light-absorption spectra of the photoanodes gradually increased, whereas the amount of dye absorption was decreased. The short-circuit current density (Jsc), open-circuit voltage (Voc), and power conversion efficiency (PCE) initially increased gradually and then decreased with increasing amounts of Ag@SiO2 NPs; the charge-transfer resistance (R2) exhibited the opposite trend. Optimal Jsc, Voc, and PCE values of 13.85 mA/cm2, 0.66 V, and 6.16%, respectively, were obtained in a DSSC containing 3 wt.% Ag@SiO2 NPs; this PCE is 43.25% higher than that of a photoanode without Ag@SiO2 NPs. The significant improvements in the properties of the optimal DSSC are attributed to the increase in the light coupling, which increased the light absorption of the dye, owing to the localized surface plasmon resonance of the Ag@SiO2 NPs.