Significantly enhanced mechanoluminescence from Nb5+ co-doped ZrO2:Sm3+via a high valence ion doping strategy

Mechanoluminescence (ML) materials, for the advantage of real-time kinetic energy to light energy conversion, are expected to have broad application prospects in the fields of stress sensing and visualization, lighting, and nondestructive stress detection. However, the deficiencies in luminescence intensity and stability limit the further application of this kind of material. In this work, a high valence ion doping strategy based on charge compensation is applied to rare-earth doped ZrO2. The enhancement of PL, afterglow, and ML properties is successfully achieved by introducing Nb5+ into the ZrO2:Sm3+ phosphor. The sample ZrO2:0.005Sm(3+),0.003Nb(5+) was obtained with great enhancement in ML intensity, 75 times higher than that of the non-doped sample. In addition, stable Tribo-ML can also be observed with the naked eye. The lifetime and intensity of AG were enhanced after co-doping with Nb5+. The afterglow emission intensity of the sample ZrO2:0.005Sm(3+),0.003Nb(5+) is about 50 times larger than that of the single-doped sample. Nb5+ not only plays the role of a charge compensator in the enhancement of luminescence intensity, but also changes the trap distribution. The proportion of the traps related to the afterglow increases, generating a new kind of deep trap suitable for ML, enhancing AG and ML as expected.