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

•A 3D starlike upconversion composite with plasmon-enhanced emission is prepared.•This composite is introduced into the scattering layer of DSSC.•Both charge transport and light harvesting are improved.•Photoelectric conversion efficiency is improved from 6.77% to 8.62%.

A plasmon-enhanced upconversion composite Y2O3:Er/Au@TiO2 (SYE/A@T) with a three-dimensional starlike morphology is prepared and then mixed with submicron TiO2 (200 nm) to form a multifunctional scattering layer in TiO2-based dye-sensitized solar cells (DSSCs). In such starlike micronsized upconverter, Au nanoparticle-assisted plasmon effect can intensify the upconversion emission of Y2O3:Er, and simultaneously TiO2 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.

Graphical abstractA three-dimensional starlike Y2O3:Er/Au@TiO2 composite is prepared and applied for a multi-functional scattering layer in dye-sensitized solar cells, exhibiting broaden absorption band of DSSC to NIR region, strong scattering efficiency, excellent charge transport property, and consequently an enhanced conversion efficiency of 8.62% due to LSPR effect of Au nanoparticles, microsized 3D UC materials and TiO2 shell.Figure optionsDownload full-size imageDownload as PowerPoint slide