Improved luminescence performance of Yb3+-Er3+-Zn2+: Y2O3 phosphor and its application to solar cells

Abstract

Upconversion materials (UC) can convert low-energy photons into visible light and, therefore, can be incorporated in solar cells to increase the absorption of visible light. This study synthesized UC nanophosphors Yb3+, Er3+: Y2O3 and Yb3+, Er3+, Zn2+: Y2O3 by a simple co-precipitation method for application in dye-sensitized solar cells (DSSCs). The impact of the enhancement in the concentration of Zn2+ on the photoluminescence (PL) and color point of the synthesized nanophosphors was also investigated. The synthesized nanophosphors emitted intense red and weaker green emissions upon excitation at 980 nm. The incorporation of Zn2+ to the Yb3+, Er3+: Y2O3 nanophosphors leads to color tunability in the red and yellow regions. Furthermore, the synthesized nanophosphors were incorporated into the DSSC photoanode to form a TiO2-UC-based DSSC for converting near-infrared (NIR) into visible light. We observed that the TiO2-UC-based DSSC showed an enhancement ratio in current density and power conversion efficiency of 17.4% and 16.6%, respectively, compared to the bare TiO2-based DSSC. These results reveal that UC-based Yb3+, Er3+, Zn2+: Y2O3 nanophosphors are useful in improving the efficiency of DSSCs and in color tunability applications.