Science and Application of Oxyorthosilicate Nanophosphors

Nanophosphor Y 2 SiO 5 :Ce (n-YSO), Lu 2 SiO 5 :Ce (n-LSO), and Gd 2 SiO 5 :Ce (n-GSO) were prepared by solution-combustion synthesis yielding nanophosphor crystallite sizes between 20 nm - 80 nm. Ce dopant concentrations were varied between 0.1%-10% for each the nanophosphors and concentration quenching curves were measured by radioluminescence (RL) and photoluminescence (PL). n-YSO exhibits concentration quenching at 1 at% and 4 at% under UV and X-ray excitation, respectively. Red shifted emission with a larger Stokes shift is observed for nanophosphors as compared to bulk crystals. The measured PL lifetime depended on the refractive index of the media, indicating that the PL originates from the surface. Measurements of the RL/PL intensity indicate that the light output of these materials is comparable to the bulk crystal.