Upconversion luminescence enhancement and color modulation in Yb3+/Er3+/Ln3+ (Ln = Tm, Ho) tri-doped YF3 microrods

Intelligent regulation of energy transfer process among different rare earth ions doped in the matrix is an effective strategy to realize high-performance upconversion (UC) luminescence. Based on this, wheat ears like Yb3+/Er3+/(Tm3+, Ho3+) triple doped YF3 microrods were fabricated via hydrothermal method, and the morphology, crystal structure, UC luminescence performance dependent on Tm3+/Ho3+ doping concentrations were studied. By comparing with the Yb3+, Er3+ co-doped YF3 microrods, the UC luminescence intensity is enhanced in Yb3+/Er3+/(Tm3+, Ho3+) triple doped YF3 samples due to the cross relaxation processes between Er3+ and Tm3+/Ho3+. Moreover, red emission is enhanced more significantly than green emission in YF3: Yb3+, Er3+, Tm3+, which is contrary to that in YF3: Yb3+, Er3+, Ho3+. The possible energy transfer upconversion mechanism involved is discussed in detail. Meanwhile, an adjustable emission color is easy to achieve via altering the doped Er3+/Tm3+/Ho3+ ion concentration. These studies on the UC luminescence enhancement mechanism of Yb3+/Er3+/(Tm3+, Ho3+) triple doped YF3 microrods are expected to provide a reference for the development of high-efficiency luminescent materials.