A novel multi-center activated single-component white light-emitting phosphor for deep UV chip-based high color-rendering WLEDs
A novel multi-center activated single-component white light-emitting phosphor for deep UV chip-based high color-rendering WLEDs
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DOI：
10.1016/j.cej.2020.124601
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发表时间：
2020-06
影响因子：
15.1
通讯作者：
Ziwang Zhang;Junhao Li;Nan Yang;Qiongyun Liang;Yi-qin Xu;Shuting Fu;Jielu Yan;Jianbang Zhou;Jianxin Shi;Mingmei Wu
中科院分区：
文献类型：
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作者：
Ziwang Zhang;Junhao Li;Nan Yang;Qiongyun Liang;Yi-qin Xu;Shuting Fu;Jielu Yan;Jianbang Zhou;Jianxin Shi;Mingmei Wu
单组分白色荧光粉用于荧光粉转换的WLED是目前固态照明领域的研究热点。Dy 3+是单组分基质产生白色光的理想材料，但其黄蓝光比例不合适和红光不足限制了其在全色显示和室内照明中的应用。本文设计并合成了一种新型的多中心激活单组分白色发光材料Sr 2LaGaO 5：Dy 3+，Sm 3+。研究发现，尽管基质和掺杂剂满足光谱重叠规律，但它们之间没有明显的能量转移，这可以从荧光粉的特殊结构中得到解释。主体和掺杂剂的共激发将是微调磷光体的发光光谱的容易策略。通过调节Dy ~（3+）和Sm ~（3+）的掺杂浓度，可以控制Dy ~（3+）在493 nm和574 nm处，Sm ~（3+）在604 nm处的发射峰的相对强度，以及基质在400 ~ 500 nm范围内的宽带发射。因此，共掺杂荧光粉的发光颜色可以从白色光调谐到橙红色，相关色温从5708 K降低到1971 K。通过将合成的荧光粉与深紫外LED芯片一起涂覆，制造了具有高达91.4的极高显色指数（Ra）的WLED器件。首次将Dy 3+和Sm 3+共激活的单组分白色荧光粉应用于高Ra的深紫外芯片激发WLED。
Single-component white light-emitting phosphors for phosphors-converted WLEDs are a hot spot of solid-state lighting field. Dy3+is a promising candidate for white light generation in single-component hosts; however, the inappropriate ratio of yellow light to blue and the lack of red light restrict its applications in full-color display and indoor lighting. Here, a novel multi-center activated single-component white light-emitting phosphor, Sr2LaGaO5:Dy3+,Sm3+, has been designed and synthesized. It is surprisingly found that there is no evident energy transfer between the host and the dopants even though they satisfy the rule of spectral overlap, which can be explained from the special structure of the phosphor. The co-excitation of the host and the dopants would be a facile strategy to finely tune the luminescent spectra of phosphors. By adjusting the doping concentrations of Dy3+and Sm3+, we can control the relative intensities of the emissions peaked at 493 nm and 574 nm from Dy3+, 604 nm from Sm3+and the broadband within the range of 400 – 500 nm from the host. Therefore, the emission color of the co-doped phosphors can be tuned from white light to orangish red region with correlated color temperature decreasing from 5708 K to 1971 K. A WLED device with extremely high color-rendering index (Ra) up to 91.4 was fabricated by coating the synthesized phosphor with a deep UV LED chip. And it is the first time to use a single-component white light-emitting phosphor co-activated with Dy3+and Sm3+in deep UV chip excited WLEDs with high Ra.