Enhanced performance of dye-sensitized solar cells via the incorporation of an internal layer consisting of three-dimensional shuttlelike up-converter and ZnO nanocrystalline aggregates

An internal layer consisting of three-dimensional (3D) shuttlelike up-converting erbium-doped yttrium oxide (Y 2 O 3 :Er 3+ ) and ZnO nanocrystalline aggregates is fabricated and implemented in photoanodes of dye-sensitized solar cells (DSCs). Such a hybrid photoanode film not only broadens the light-absorbing range to near-infrared region by incorporation of up-converting material but also generates significant light scattering arising from both the micron-sized shuttlelike Y 2 O 3 :Er 3+ and submicron-sized ZnO aggregates as confirmed by the optical characterizations. Owing to the synergic improvement of light harvesting, the overall photo-to-current conversion efficiency (PCE) of ZnO-DSC is significantly improved from 4.08% to 5.63% with an optimized doping amount of 11% Y 2 O 3 :Er 3+ in the internal layer. Further, a competitive PCE of 6.26% is also achieved for a tiny-sized device with 11% Y 2 O 3 :Er 3+ , suggesting the substantial potential of 3D up-converting material in improving DSC performance.