Enhancement of low energy sunlight harvesting in dye-sensitized solar cells using plasmonic gold nanorods

This communication describes the use of Ag2S-encapsulated Au nanorods (AuNR@Ag2S) to enhance longer wavelength sunlight utility in dye-sensitized solar cells (DSSCs). We observed that the longitudinal plasmon resonance of AuNRs induces a remarkable increase of 37.6% in photocurrent generation at 600-720 nm. Optical characterizations indicate that the increased optical density and decreased light transmission as a result of AuNRs incorporation engender the striking improvement. With AuNR@Ag2S, the final power conversion efficiency (PCE) of the DSSC with a thin anode (6 mu m) increases from 4.3% to 5.6%, which is comparable to that of a pure TiO2 anode based DSSC (5.8%) with a film thickness of 11 mm. Further, incorporation of AuNR@Ag2S into the thick anode leads to the PCE increasing to 7.1%.