发光学报, 2020, 41 (3): 271, 网络出版: 2020-03-25  

白光LED用Li+/La3+共掺杂BaSi2O5∶Eu2+绿光发射荧光粉的制备及其发光性能和热稳定性

Preparation, Luminescence and Thermal Stability of Li+/La3+ Co-doped Single-phased BaSi2O5∶Eu2+ Green Emitting Phosphors for White LEDs
作者单位
东北师范大学 物理学院, 吉林 长春 130024
摘要
通过Li+/La3+同比例共掺杂策略, 在氢气气氛下烧结制备了Li0.06La0.06Ba0.84Si2O5∶4%Eu2+ (LLBSO∶Eu2+)高效绿色发光荧光粉。相比于未掺杂样品Ba0.96Si2O5∶4%Eu2+ (BSO∶Eu2+), Li+/La3+共掺有助于单一相LLBSO∶Eu2+荧光粉的合成, 能有效降低烧结的温度和缩短合成时间。我们发现该策略节约荧光粉合成成本的同时, 也可以显著提高其光学性能。相关测试表明, Li+/La3+共掺杂样品平均颗粒尺寸主要分布在1.1~2.7 μm, 颗粒团聚现象不明显, 符合涂覆LED芯片要求。该样品可以有效地被365 nm近紫外LED芯片激发, 产生位于502 nm的强的宽带绿光发射, 其归属于Eu2+的5d-4f跃迁, 发光强度是未掺杂样品的168%。此外, LLBSO∶Eu2+荧光粉在150 ℃时发光强度仍保持在室温时的98%左右, 具有良好的热稳定性。该样品CIE坐标位于绿光区(0.217, 0.410)。通过绿粉/红粉和绿粉/红粉/蓝粉混粉策略, 制得了色温为2 918~4 037 K的白色发光LED, 其显色指数(Ra)均大于85, 具有良好的热稳定性。实验结果表明, Li+/La3+共掺单一相的BSO∶Eu2+绿色发光荧光粉是制备近紫外激发白光发射LED的优良候选荧光粉材料。
Abstract
Li+/La3+ co-doped Li0.06La0.06Ba0.84Si2O5∶4%Eu2+ (LLBSO∶Eu2+) green-emitting phosphors were prepared through a high-temperature solid state reaction. Compared with undoped Ba0.96Si2O5∶4%Eu2+ (BSO∶Eu2+) sample, it can be found that Li+/La3+ co-doping is an efficient strategy for synthesizing single-phased LLBSO∶Eu2+ at lower temperature in less synthesis time. Our results indicate that this strategy can lead to not only the reduced cost but also the improved optical performances. The related tests suggest that, for Li+/La3+ co-doped BSO∶Eu2+ phosphors, the particle size is in the range of 1.1-2.7 μm and no obvious aggregation can be found, suggesting that it meets the requirements for coating LED chips. Upon near-ultraviolet LED chip (365 nm) excitation, LLBSO∶Eu2+ exhibits a strong broadband emission around 502 nm, which is attributed to the 5d-4f transition of Eu2+. Its luminescent intensity reaches 168% as strong as that of the undoped sample. Furthermore, for LLBSO∶Eu2+ phosphor, the luminescent intensity measured at 150 ℃ is ~98% as strong as that measured at room temperature, suggesting it has good thermal stability. The CIE coordinate of LLBSO∶Eu2+ phosphors is (0.217, 0.410), which locates in the green light region. White LEDs with different color temperatures ranging from 2 918 K to 4 037 K, were fabricated using blend strategies. These LEDs exhibit high color rendering index (Ra>85) and good thermal stability. Our studies suggest that LLBSO∶Eu2+ green-emitting phosphor is one kind of candidates for fabricating near-ultraviolet excited white LEDs.

黄晓松, 姜荣云, 杨健, 刘春光, 祝汉成, 严端廷, 徐长山, 刘玉学. 白光LED用Li+/La3+共掺杂BaSi2O5∶Eu2+绿光发射荧光粉的制备及其发光性能和热稳定性[J]. 发光学报, 2020, 41(3): 271. HUANG Xiao-song, JIANG Rong-yun, YANG Jian, LIU Chun-guang, ZHU Han-cheng, YAN Duan-ting, XU Chang-shan, LIU Yu-xue. Preparation, Luminescence and Thermal Stability of Li+/La3+ Co-doped Single-phased BaSi2O5∶Eu2+ Green Emitting Phosphors for White LEDs[J]. Chinese Journal of Luminescence, 2020, 41(3): 271.

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