Utilizing energy transfer strategy to produce efficient green luminescence in Ca2LuHf2Al3O12:Ce3+,Tb3+ garnet phosphors for high-quality near-UV-pumped warm-white LEDs.
Utilizing energy transfer strategy to produce efficient green luminescence in Ca2LuHf2Al3O12:Ce3+,Tb3+ garnet phosphors for high-quality near-UV-pumped warm-white LEDs.
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DOI：
10.1016/j.jcis.2021.05.108
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发表时间：
2021-05
影响因子：
9.9
通讯作者：
Nan Ma;Wei Li;Balaji Devakumar;Zongjie Zhang;Xiaoyong Huang
中科院分区：
文献类型：
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作者：
Nan Ma;Wei Li;Balaji Devakumar;Zongjie Zhang;Xiaoyong Huang
白色发光二极管（LED）广泛应用于照明和显示器件中，探索发光性能优异、稳定性好的荧光粉是白色LED发展的关键。本文报道了一种新型的近紫外激发的绿色荧光材料Ca 2LuHf 2（AlO 4）3：Ce 3+，Tb 3+石榴石，该材料具有高效的Ce 3 +→ Tb 3+能量转移。采用高温固相法成功合成了CLHA：Ce 3+，Tb 3+绿色荧光粉，并通过X射线衍射、场发射扫描电镜、X射线能谱、元素分布、光致发光谱、CIE色坐标、量子效率和变温发射光谱等手段对荧光粉进行了表征。由于Ce ~（3+）离子的自旋允许4f → 5d跃迁，CLHA：Ce ~（3+），Tb ~（3+）荧光粉在300-470 nm近紫外（near-UV）范围内具有较强的宽激发带。在408 nm激发下，CLHA：Ce 3+，Tb 3+荧光粉显示出较强的绿色光，发射中心位于543 nm。Ce ~（3+）与Tb ~（3+）之间的能量传递机制属于四重-四重相互作用。实验结果表明，最佳的CLHA：0.02Ce 3+，0.5Tb 3+绿色荧光粉的内量子效率和外量子效率分别为77.1%和55.8%。最后，采用CLHA：0.02Ce3+，0.5Tb3+荧光粉作为绿光转换体，制备了近紫外泵浦的白色LED器件，在80 mA驱动电流下，该LED器件表现出明亮的暖白色光，具有高显色指数（93.7）、低相关色温（3574 K）、CIE色坐标（0.3922，0.3633）和高光效（29.35 lm/W）。
White light-emitting diodes (LEDs) are widely used in lighting and display devices, and the exploration of phosphors with excellent luminescence performance and good stability is the key to the development of white LEDs. In this work, we reported novel near-UV-excited green-emitting Ca2LuHf2(AlO4)3:Ce3+,Tb3+garnet phosphors with efficient Ce3+→ Tb3+energy transfer. The CLHA:Ce3+,Tb3+green phosphors were successfully synthesized by a high-temperature solid-state method, and the phosphors were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, photoluminescence excitation and photoluminescence spectra, the Commission International de I’Eclairage (CIE) chromaticity coordinates, quantum efficiency and temperature-dependent emission spectra. Due to the spin-allowed 4f → 5d transition of Ce3+ions, the CLHA:Ce3+,Tb3+phosphors exhibited a strong broad excitation band in the 300–470 nm near-ultraviolet (near-UV) range. Under 408 nm excitation, the CLHA:Ce3+,Tb3+phosphors showed strong green light with emission center at 543 nm. The mechanism of energy transfer from Ce3+to Tb3+ions was attributed to quadruple-quadruple interaction. Impressively, the internal quantum efficiency and external quantum efficiency of the optimal CLHA:0.02Ce3+,0.5Tb3+green phosphors were measured to be 77.1% and 55.8%, respectively. Finally, using the CLHA:0.02Ce3+,0.5Tb3+phosphors as green-emitting color converter, a near-UV-pumped white LED device was fabricated, and under 80 mA driving current the LED device demonstrated bright warm-white light with high color rendering index (93.7), low correlated color temperature (3574 K), CIE chromaticity coordinates (0.3922, 0.3633), and high luminous efficacy (29.35 lm/W).