Huang Xiaoyong, Guo Heng
Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, College of Physics and Optoelectronics, Taiyuan University of Technology Taiyuan 030024 PR China
RSC Adv. 2018 May 10;8(31):17132-17138. doi: 10.1039/c8ra03075h. eCollection 2018 May 9.
Single-component white-emitting phosphors are highly promising for applications in phosphor-converted white light-emitting diodes. In this paper, novel single-phase LiCaZnVO:Eu ( = 0-0.05) phosphors with tunable white emissions were prepared by a conventional solid-state reaction. The LiCaZnVO ( = 0) phosphor showed an efficient self-activated bluish-green emission due to the V-O charge transfer transition of the [VO] groups, and possessed an intense broad excitation spectrum in the 250-400 nm wavelength range. Together with the [VO] emission, the red emission of Eu ions was also observed in LiCaZnVO:Eu phosphors. The energy transfer from the [VO] groups to the Eu ions was studied. Importantly, the emission colors of LiCaZnVO:Eu phosphors varied from greenish-blue to whitish and then to red with increasing Eu content and the white-light emission was realized in the single-phase phosphor of LiCaZnVO:0.003Eu by combining the [VO]-emission and the Eu-emission. The energy-transfer efficiency from [VO] groups to Eu ions in the LiCaZnVO:0.003Eu sample was determined to be about 52% and the internal quantum efficiency of the LiCaZnVO:0.003Eu phosphor was found to be about 41.5%. In addition, the CIE chromaticity coordinates of LiCaZnVO:0.003Eu were ( = 0.3374, = 0.3596), and the correlated color temperature was estimated to be about 5311 K.
单组分白色发光磷光体在用于磷光体转换白光发光二极管方面具有很大的应用前景。本文通过传统的固态反应制备了具有可调白色发射的新型单相LiCaZnVO:Eu（x = 0 - 0.05）磷光体。LiCaZnVO（x = 0）磷光体由于[VO]基团的V - O电荷转移跃迁而呈现出高效的自激活蓝绿色发射，并且在250 - 400 nm波长范围内具有强烈的宽激发光谱。在LiCaZnVO:Eu磷光体中，除了[VO]发射外，还观察到了Eu离子的红色发射。研究了从[VO]基团到Eu离子的能量转移。重要的是，随着Eu含量的增加，LiCaZnVO:Eu磷光体的发射颜色从绿蓝色变为白色然后变为红色，并且通过结合[VO]发射和Eu发射在LiCaZnVO:0.003Eu的单相磷光体中实现了白光发射。LiCaZnVO:0.003Eu样品中从[VO]基团到Eu离子的能量转移效率被确定为约52%，并且发现LiCaZnVO:0.003Eu磷光体的内量子效率约为41.5%。此外，LiCaZnVO:0.003Eu的CIE色度坐标为（x = 0.3374，y = 0.3596），相关色温估计约为5311 K。
