Application of upconversion luminescence in dye-sensitized solar cells

An upconversion luminescence powder TiO2:(Er3+, Yb3+) is prepared by a hydrothermal method and used to fabricate dye-sensitized solar cell (DSSC). The TiO2:(Er3+, Yb3+) powder undergoes upconversion luminescence, converting infrared light which the dye can not absorb into visible light with wavelengths of 510-700 nm which the dye can absorb, increasing the photocurrent of the DSSC. TiO2:(Er3+, Yb3+) also acts as a p-type dopant, heightening the Fermi level of the oxide film, which increases the photovoltage of the DSSC. The best performance of the DSSC is found when the ratio of TiO2/luminescence powder is 1/3 in the luminescence layer. Under simulated solar irradiation of 100 mW cm-2 (AM 1.5), the DSSC containing TiO2:(Er3+, Yb3+) doping achieves a light-to-electricity energy conversion efficiency of 7.28% compared with 6.41% for the undoped DSSC.