Highly modulated structure and upconversion photoluminescence properties of PbGd2(MoO4)4:Er3+/Yb3+ phosphors

Abstract Double molybdate of PbGd 2− x (MoO 4 ) 4 :Er 3+ /Yb 3+ phosphors with the correct doping concentrations of Er 3+ and Yb 3+ ( x = Er 3+ + Yb 3+ , Er 3+ = 0.05, 0.1, 0.2 and Yb 3+ = 0.2, 0.45) were successfully synthesized by microwave sol–gel process. The highly modulated structure and the upconversion photoluminescence properties were investigated in detail. The synthesized particles, formed after heat-treatment at 900 °C for 16 h, showed a well ctystallized morphology with particle sizes of 2–5 μm. Under excitation at 980 nm, the PbGd 1.7 (MoO 4 ) 4 :Er 0.1 Yb 0.2 and PbGd 1.5 (MoO 4 ) 4 :Er 0.05 Yb 0.45 particles exhibited a strong 525-nm emission band, a weak 550-nm emission band in the green region, and a very weak 655-nm emission band in the red region. The Raman spectra of the doped particles indicated the disordered structures of PbGd 2− x (MoO 4 ) 4 by the incorporation of the Er 3+ and Yb 3+ ions into the crystal lattice, which resulted in the highly modulated structure as well as a concentration quenching effect of Er 3+ ions.