Synthesis and photoluminescence properties of Eu 3+ -activated LiCa 3 ZnV 3 O 12 white-emitting phosphors.

Single-component white-emitting phosphors are highly promising for applications in phosphor-converted white light-emitting diodes. In this paper, novel single-phase LiCa 3(1- x ) ZnV 3 O 12 :Eu 3+ ( x = 0-0.05) phosphors with tunable white emissions were prepared by a conventional solid-state reaction. The LiCa 3 ZnV 3 O 12 ( x = 0) phosphor showed an efficient self-activated bluish-green emission due to the V 5+ -O 2- charge transfer transition of the [VO 4 ] 3- groups, and possessed an intense broad excitation spectrum in the 250-400 nm wavelength range. Together with the [VO 4 ] 3- emission, the red emission of Eu 3+ ions was also observed in LiCa 3(1- x ) ZnV 3 O 12 :Eu 3+ phosphors. The energy transfer from the [VO 4 ] 3- groups to the Eu 3+ ions was studied. Importantly, the emission colors of LiCa 3(1- x ) ZnV 3 O 12 :Eu 3+ phosphors varied from greenish-blue to whitish and then to red with increasing Eu 3+ content and the white-light emission was realized in the single-phase phosphor of LiCa 3 ZnV 3 O 12 :0.003Eu 3+ by combining the [VO 4 ] 3- -emission and the Eu 3+ -emission. The energy-transfer efficiency from [VO 4 ] 3- groups to Eu 3+ ions in the LiCa 3 ZnV 3 O 12 :0.003Eu 3+ sample was determined to be about 52% and the internal quantum efficiency of the LiCa 3 ZnV 3 O 12 :0.003Eu 3+ phosphor was found to be about 41.5%. In addition, the CIE chromaticity coordinates of LiCa 3 ZnV 3 O 12 :0.003Eu 3+ were ( x = 0.3374, y = 0.3596), and the correlated color temperature was estimated to be about 5311 K.