Enhancement of the near-infrared emission of Ce3+–Yb3+ co-doped Y3Al5O12 phosphors by doping Bi3+ ions

Abstract

Ce³⁺–Yb³⁺ co-doped Y₃Al₅O₁₂ phosphors are one of most the potential candidates of down-conversion materials for photovoltaic cells. To improve the near-infrared emission from Yb³⁺ ions, Bi³⁺ ions were introduced into the phosphors. The experimental results showed that the intensity of Yb³⁺ emission was greatly enhanced after doping Bi³⁺ ions into the phosphors. This may be attributed to an additional pathway via Bi³⁺ ions for the energy transfer from Ce³⁺ to Yb³⁺. Different from the co-doped phosphors, where the energy of Ce³⁺ ions was transferred only to Yb³⁺ ions, in Bi³⁺–Ce³⁺–Yb³⁺ tri-doped phosphors, the energy of Ce³⁺ ions could be transferred not only to Yb³⁺ ions but also to Bi³⁺ ions. Then, Bi³⁺ ions transferred part of the energy to Yb³⁺ ions. This enabled Yb³⁺ ions to obtain more energy and enhance their near-infrared emission.