Enhanced efficiency in quantum confined YBO3:Tb3+ nanophosphor

Quantum confined Tb3+ ion doped in YBO3 nanocrystal yield enhancement in luminescence under 254 nm (UV) excitation as compared to Tb3+ ion doped in YBO3 bulk phosphor. The terbium ion doped YBO3 nanocrystals have particle size 9–20 nm, while, YBO3:Tb3+ bulk phosphor particles are of 100–300 nm in size. Photoluminescence excitation peak shifts to higher energy with decrease of particle size. Enhanced luminescence in YBO3 nanocrystal is explained on basis of modulation of f–f transition due to qunatum confinement of Tb3+ ion in YBO3 host. The enhancement in emission intensity in YBO3:Tb3+ nanophosphor was not observed at 147 nm (VUV) excitation. It is considered that the diminished emission intensity at 147 nm excitation may be due to low penetration depth of VUV radiation as well as increase of surface defects responsible for non-radiative transition in nanoparticles.