Optical studies of Y3(Al,Ga)5O12:Ce3+,Cr3+,Nd3+nano-phosphors obtained by the Pechini method

The Y3(Al,Ga)5O12:Ce3+,Cr3+,Nd3+(YAGG) nano-phosphors with homogeneous particle-size distribution, low aggregation and average crystalline size of about 65 nm were obtained using a modified Pechini method. Only slight aggregation of the crystallites occurs after post-annealing at 1100 °C. The intense Ce3+bands in the excitation spectra of the Ce3+,Cr3+,Nd3+co-doped materials monitoring the Cr3+emission at 690 nm indicate energy transfer from Ce3+to Cr3+. Weak Nd3+lines are observed, as well. In addition, the emission of Nd3+at 1060 nm with excitation of Ce3+and Cr3+confirms the Ce3+/Cr3+to Nd3+energy transfer. The short average luminescence decay times for the Ce3+emission indicate the Ce3+/Cr3+to Nd3+energy transfer. Eventually, the Y3(Al,Ga)5O12:Ce3+,Cr3+,Nd3+nano-phosphors exhibit persistent luminescence originating from the 4f3→ 4f3transitions of Nd3+which matches well to the first biological window to be used in bioimaging applications.