Tunable ultraviolet/visible to near-infrared down-conversion luminescence in the Er3+, Yb3+ co-doped (Y0.88La0.09Zr0.03)2O3 transparent ceramics

Herein, we report an efficient ultraviolet/visible to near-infrared (NIR) down-conversion luminescence phenomenon in transparent Er3+, Yb3+ co-doped (Y0.88La0.09Zr0.03)2O3 ceramics. Almost fully densified (Y0.88La0.09Zr0.03)2O3 transparent ceramic has been prepared by vacuum sintering at 1800 °C with different contents of Er3+ and Yb3+ elements. The intensity ratio of Yb3+: 2F5/2 → 2F7/2 emission (∼1000 nm) to the Er3+: 4I13/2 → 4I15/2 emission (∼1550 nm) has been tuned by adjusting the excitation wavelength. Phonon-assist quantum cutting from the 4G11/2 level of Er3+ with two energy transfer (ET) processes to Yb3+ has been determined, which enhances the Yb3+ emission around the wavelength of 1000 nm. It is found that when one photon around 379 nm is absorbed, two photons around 1000 nm will be emitted, and hence the quantum efficiency is estimated to be ∼182% in this transparent ceramics. The mechanism of the visible to near-infrared (NIR) down-conversion luminescence in the Er3+, Yb3+ co-doped (Y0.88La0.09Zr0.03)2O3 ceramics has been discussed.