Integrated plasmonic and upconversion starlike Y2O3:Er/Au@TiO2 composite for enhanced photon harvesting in dye-sensitized solar cells

Abstract A plasmon-enhanced upconversion composite Y 2 O 3 :Er/Au@TiO 2 (SYE/A@T) with a three-dimensional starlike morphology is prepared and then mixed with submicron TiO 2 (200 nm) to form a multifunctional scattering layer in TiO 2 -based dye-sensitized solar cells (DSSCs). In such starlike micronsized upconverter, Au nanoparticle-assisted plasmon effect can intensify the upconversion emission of Y 2 O 3 :Er, and simultaneously TiO 2 coating can improve the charge transport within SYE/A@T. Therefore, the SYE/A@T shows extended light-absorbing range to near-infrared region and improved light-scattering ability, leading to an improved photovoltaic performance of DSSCs. With the optimum mixing ratio, a conversion efficiency of 8.62% is attained, which is a significant improvement of 27.6% compared with the cell without adding SYE/A@T. Our work provides a feasible strategy to prepare an upconversion composite with plasmon-enhanced emission and enable this composite to accommodate the DSSCs system and improve the conversion efficiency of DSSCs.