The upconversion luminescences of YAlO<sub>3</sub>:Er<sup>3+</sup> phosphor co-doping with different Gd<sup>3+</sup> concentrations are investigated under the excitation of 980- and 532-nm diode lasers. A near ultraviolet upconversion emission at 410 nm is observed in YAlO<sub>3</sub> under 532-nm excitation. Moreover, the inactive Gd<sup>3+</sup> ions can improve the upconversion intensity efficiently in a certain range of concentration. Under 980-nm excitation, the visible upconversion emissions at 546 and 646 nm are enhanced by about 10 and 8 times at the Gd<sup>3+</sup> concentration of 40%, respectively. The upconversion emission at 410 nm under 532-nm excitation is also enhanced by 7 times. The substitution of Gd<sup>3+</sup> ions for Y<sup>3+</sup> sites changes the local symmetry of Er<sup>3+</sup>, leading to the improvement of upconversion efficiency.
© 2012 Chinese Optics LettersPDF Article