Doping modification of YVO₄:Eu³⁺ down-conversion materials for solar cell applications

Bismuth (Bi³⁺) and phosphorus (P³⁺) ions doped YVO₄:Eu³⁺ down-conversion materials were prepared by modified sol-gel method to broaden the absorption range of ultraviolet light and enhance the stability of light emission. It is shown that some positions of Yttrium (Y³⁺) and Vanadium (V⁵⁺) ions can be successfully replaced by incorporated Bismuth (Bi³⁺) and phosphorus (P³⁺) ions in the YVO₄ lattice. As to low Bi³⁺ doping, the crystal structure is still tetragonal and the position of Y³⁺ is well substituted by Bi³⁺. While for low P³⁺ doping, a homogeneous solid solution is formed between YVO₄ and YPO₄.Under the excitation of 325 nm, the highest luminescence intensity can be obtained with Bi³⁺ mole fraction of 0.04 and P⁵⁺ mole fraction of 0.10, respectively. In that case, the instensity of YV_0.90P_0.10O₄:0.05Eu³⁺ can increase up to 1.9 times comparing to YVO₄:0.05Eu³⁺.