Novel multiband luminescence of Y2Zr2O7:Eu3+, R3+ (R = Ce, Bi) orange-red phosphors via a sol-gel combustion approach

A novel class of orange-red phosphors Y2Zr2O7:Eu3+, R3+ (R = Ce, Bi) was successfully fabricated by a facile sol-gel combustion method. XRD, TG-DTA and SEM results show that the heat-treatment of the powders at 800 degrees C is enough to obtain highly crystallized Y2Zr2O7 samples. Photoluminescence spectra of the Eu3+-doped nanoparticles illuminated the simultaneous occurrence of several intense orange-red band emissions corresponding to the f-f transitions D-5(0)-F-7(J) (J = 1, 2, 3, 4 and 5) of Eu3+ under 395 nm excitation. The photoluminescence spectra of Y2Zr2O7:Eu3+, R3+(R = Ce, Bi) showed that the luminescence intensity of Y2Zr2O7:Eu3+ was greatly enhanced by Ce3+ and Bi3+ by 260% and 165%, respectively. The possible sensitization mechanisms of Ce3+ and Bi3+ on Eu3+ emission intensity have been investigated and discussed in detail. The high brightness confirmed the potential applications of the phosphors in display devices and light-emitting diodes. (C) 2012 Elsevier B.V. All rights reserved.