白光LED用新型黄色发光材料：川黄柏

来源：Scientific Reports 7, Article number: 9009(2017)

台湾中原大学Pin-Chun Lin等人近日在《Scientific Reports》上发表研究成果《Phellodendron chinense Schneid: A novel yellow-emitting luminescent material for white light-emitting diodes》。他们从天然川黄柏树皮中萃取出了黄色荧光粉，并将这种黄色荧光粉引入白光LED的制作中，通过组合蓝光LED芯片和Y₃Al₅O₁₂:Ce³⁺ 荧光粉，产生出了温暖的白光。这种新型荧光粉的发射波长为540nm，半高宽（FWHM）为120nm，吸收带范围为350nm—525nm，CIE色坐标为（0.41，0.55），且在380nm激发波长下其发光强度比 YAG:Ce荧光粉的要高出139%。

Phellodendron chinense Schneid: A novel yellow-emitting luminescent material for white light-emitting diodes

Pin-Chun Lin, Kuei-Ting Hsu,Ming-Hsiu Shiu,Wei-Ren Liu

Abstract：

To facilitate the next generation of environmental material for white light emitting diodes, the discovery of natural luminesce is essential. In this study, we disclose a rare-earth free and yellow-emission phosphor, Phellodendron, which could be both excited by near ultraviolet light and blue light. The new yellow phosphor is obtained by extraction of Phellodendron chinense Schneid. The emission wavelength, full width at half maximum and CIE coordinates of extracted Phellodendron are 540nm, 120nm and (0.41, 0.55), respectively. The corresponding luminescent properties of Phellodendron are characterized by PL, PLE, reflection spectra, FITR and decay lifetime. Surprising thing is luminous intensity of Phellodendron phosphors excited at 380nm was stronger than YAG:Ce phosphor by more than 139%. In addition, we firstly introduce the yellow phosphor in white LED fabrication by combining blue chip and Y₃Al₅O₁₂:Ce³⁺ phosphor, to create warm white. For comparison, red-emission CaAlSiN₃:Eu²⁺ phosphors are also introduced for LED package tests. The results demonstrate that Phellodendron is a potential candidate for white LED applications.

Figure1:(a) Schematic of the extracted device for Phellodendron phosphor; (b) Illustration of w-LEDs packaged for LEDs; (c) Photograph of Phellodendron phosphor excited at 254 nm and 365 nm in UV box.

Figure2:(a) FT-IR spectrum of Phellodendron phosphor; (b) UV visible absorption spectrum of Phellodendron phosphor; (c) Direct band gap estimation of Phellodendron phosphor; (d) Indirect band gap estimation of Phellodendron phosphor; (e) Relative photoluminescence excitation and emission spectra of Phellodendron phosphor (filled area) and YAG:Ce (dotted curves); (f) The PL decay spectrum of Phellodendron phosphor monitored at the emission peak (orange line). The dash line shown in (f) is a fitting result according to Eq. (2).

Figure3:(a) CIE chromaticity diagram of Phellodendron phosphor (D), YAG phosphor (Y) and CaAlSiN₃:Eu²⁺ phosphor (R). Insets: the images of samples excited with blue light in box; (b) CIE chromaticity diagram of w-LEDs coupling the 460 nm blue chip with LEDs (*: LED (1), ×: LED (2), o- LED (3)); (c) CIE chromaticity diagram of LEDs with different content (0, 0.1, 2.4, 9.1, 50%) Phellodendron phosphor; (d) Photographs of the LED lamp packages under 30 mA forward bias currents; (e) Color correlated temperature (CCT) of LED (1), LED (2) and LED (3).

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