Host-Sensitized NIR Quantum Cutting Emission in Nd3+ Doped GdNbO4 Phosphors and Effect of Bi3+ Ion Codoping

Abstract

Host-sensitized near-infrared quantum cutting (QC) emission has been demonstrated in Nd3+ doped Gd1-xNdxNbO4 phosphors for various x values. Further, the effect of Bi3+ ion addition as a sensitizer on near-infrared QC is studied in detail. X-ray diffraction confirms a monoclinic structure for pure and Nd3+ doped phosphors. Pulsed laser excitation at 266 nm of Gd1-xNdxNbO4 and Gd(0.99-x)NdxBi0.01NbO4 causes efficient room-temperature energy transfer from the NbO43- to the Nd3+ ions and the NbO43- and Bi3+ ions to the Nd3+ ions, respectively, which emits more than one near-infrared photon for single impinging ultraviolet photon. The emission band of Nd3+ shows unusual character where the intensity of the 4F3/2-4I9/2 transition at 888 nm is higher than the intensity of the transition 4F3/2-4I11/2 at 1064 nm, due to energy transfer from GdNbO4 host to Nd3+ ion. Using photoluminescence lifetime studies, the quantum cutting efficiencies are found to be the maximum 166% and 172% for Gd(0.95)Nd0.05NbO4 and Gd(0.94)Nd0.05Bi0.01NbO4, respectively. The present study could establish Nd3+ ion as an alternative of Yb3+ ion for near-infrared quantum cutting. This work facilitates the probing of Nd3+ ions doped phosphor materials for next generation Si-solar cells.