全光谱白光发光二极管用Eu3+掺杂Ca2KZn2(VO4)3黄色荧光粉的制备及光学性能

基于蓝光芯片激发黄色荧光粉或近紫外芯片激发三基色荧光粉构建的白光发光二极管(WLED)在青光区域呈现明显的凹口,导致白光的色彩性能不够理想。为了弥补这一缺陷,实现全光谱白光,我们设计了Eu³⁺掺杂Ca₂KZn₂(VO₄)₃黄色荧光粉,其发射波长范围为400~750 nm。在387 nm激发下,在所制荧光粉中可同时获得来自VO₄^3-基团和Eu³⁺的发射光。Eu³⁺在Ca₂KZn₂(VO₄)₃基质中的最佳掺杂浓度(物质的量分数)为0.05,且VO₄^3-基团向Eu³⁺的能量传递效率达到64.9%。基于变温的发射光谱,揭示了所制荧光粉的热稳定性并发现VO₄^3-基团和Eu³⁺的激活能分别为0.538和0.510 eV。此外,将所制黄色荧光粉与商用蓝色荧光粉和近紫外芯片进行封装整合,得到可发射暖白光的WLED器件,其色温和显色指数分别为3843 K和85.8。

Synthesis and Optical Properties of Eu3+-Doped Ca2KZn2(VO4)3 Yellow-Emitting Phosphors for Full-Spectrum White Light-Emitting Diode

Traditional phosphor-converted white light-emitting diode (WLED), which is constructed either by using a blue-chip to pump yellow phosphors or a near-ultraviolet (NUV) chip to excite trichromatic phosphors, suffers from an evident cavity in the cyan region, resulting in the unsatisfied color quality of the white light. Thereby, Eu³⁺-doped Ca₂KZn₂ (VO₄)₃ yellow-emitting phosphors with the emission in a range of 400-750 nm were prepared to cover this spectral gap to obtain the full-spectrum white light. Excited by 378 nm, both the emissions arising from VO₄^3- group and Eu³⁺ were seen in the prepared samples. The optimal doping content (molar fraction) for Eu³⁺ ions in the Ca₂KZn₂(VO₄)₃ host was 0.05 and energy transfer efficiency from VO₄^3- group to Eu³⁺ was calculated to be around 64.9%. The thermal quenching performances of the final compounds were investigated via the use of the temperature-dependent emission spectra and the activation energies of the VO₄^3- group and Eu³⁺ were 0.538 and 0.510 eV, respectively. In addition, a WLED device using the prepared yellow-emitting phosphors, commercial blue phosphors, and NUV chip exhibited well-distributed warm white light with low color correlated temperature of 3 843 K and high color rendering index of 85.8.