Near-Infrared Luminescence from Y2O3:Eu3+, Yb3+ Prepared by Sol-Gel Method

Eu3+ and Yb3+ codoped Y2O3 phosphors were synthesized by the sol-gel method. The phosphors possess absorption in the region of 300-550 nm, exhibiting an intense NIR emission of Yb3+ around 1000 nm, which is suitable for matching the maximum spectral response of c-Si solar cells. The optimum composition of Eu3+ and Yb3+ codoped Y2O3 was (Y1.94Yb0.04Eu0.02)(2)O-3. It is observed that two-step energy transfer occurs from the D-5(2) level of Eu3+ situated around (466 nm) exciting two neighboring Yb3+ ions to the F-2(5/2) level (1000 nm). The down-conversion material based on Eu3+-Yb3+ couple may have great potential applications in c-Si solar cells to enhance their photovoltaic conversion efficiency via spectral modification.