Tunable luminescence and energy transfer properties of GdPO_4:Tb~(3+), Eu~(3+) nanocrystals for warm-white LEDs

摘要

In this work, we synthesized highly uniform and well-dispersed hexagonal phase GdPO4 nanorods by hydro thermal method at 180 degrees C, which were transformed to GdPO4 nanocrystals with the monoclinic phase upon heating above 800 degrees C. The phase transformation process and photoluminescence properties of as-prepared samples were investigated via XRD, FE-SEM, and PL spectroscopy. The integrated emission intensity of GdPO4:0.07 Tb3+ (monoclinic) is almost 2.62 times stronger than that of GdPO4 center dot H2O:0.07 Tb3+ (hexagonal). By codoping the Tb3+ and Eu3+ ions into the GdPO4 host, the emitting colors could be adjusted from the green to warm white due to the efficient energy transfer from Tb3+ to Eu3+ at 368 nm excitation. Moreover, the energy transfer from Tb3+ to Eu3+ was revealed to be resonant type by quadrupole-quadrupole mechanism, and the energy transfer efficiency of GdPO4:Tb3+, y Eu3+ reached about 96.1% when the concentration unit of Eu3+ was 12 mol%. These merits demonstrate that this material may find potential application in warm-white display fields.