LAUSR

The correlations between the crystal structures and photoluminescence (PL) properties of Lu3Al5−xGaxO12:Ce3+ powders were investigated. The Ce4+→Ce3+ reduction could be achieved during calcination under air atmosphere at a high temperature of 1700 °C through charge compensation. Upon increasing Ga content (x), the lattice constant of the unit cell gradually increased, and the particle size increased accordingly. The PL spectra exhibited asymmetric emission bands of Ce3+ in the green region. The increase in x shifted the emission peaks toward shorter wavelengths owing to the larger Ga3+ ion. The effects of the Ga3+ substitution on the PL spectra can be explained in terms of the Ce–O-bond length and crystal field splitting of the Ce3+ ions. The Ga3+ substitution provided tunable light emission (from green to cyan), which improves the application flexibility of the Lu3Al5O12:Ce3+ phosphor.