Application of upconversion luminescence in dye-sensitized solar cells

Abstract

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.