单基质白光LED荧光粉研究进展

doi:10.15541/jim20190045

摘要/Abstract

摘要：

白光LEDs(White Light-Emitting Diodes, WLEDs)作为一种新型的固体照明光源, 相对于已有光源(白炽灯、荧光灯等)具有发光效率高、响应速度快、寿命长等优势, 在照明和显示领域有着广阔的应用前景。目前获取WLEDs最常用的方法是蓝光LED芯片激发YAG : Ce ³⁺黄光荧光粉以及紫外-近紫外芯片激发三基色荧光粉(RGB混合荧光粉), 相比于以上两种方式, 单基质WLEDs荧光粉由于能克服传统RGB荧光粉颜色再吸收及配比调控的问题, 获得较高的流明效率及较高色彩还原性而受到越来越多的关注。目前关于单基质白光荧光的研究已有大量文献报道, 涉及多种材料体系, 按照发光原理的不同, 可以将其地简单分为单离子激发体系、多离子激发体系以及不依赖于稀土离子发光的其他体系等。本文综述了单基质WLEDs荧光粉的研究进展, 指出了其发展中存在的问题, 并对未来发展趋势作了展望。

关键词: WLEDs, 单基质, 白光荧光粉, 综述

Abstract:

As a new solid-state lighting source, the white light-emitting diodes (WLEDs) have a greatly promising application in the field of lighting and display. They have superior advantages of high luminous efficacy, fast response speed and long service life, etc. compared with the existing light sources (incandescent lamps, fluorescent lamps, etc.). At present the WLEDs are commonly fabricated by combination of a blue LED chip and YAG: Ce ³⁺ yellow-emitting phosphor, and combination of a ultraviolet-near ultraviolet excitation chip and red-green-blue (RGB) emitting color phosphors, compared with the above two phosphors, the single-phase phosphors containing white emission have the advantages of a higher luminous efficacy, color rendering. Meanwhile, the single-phase phosphors may effectively solve the reabsorption problem existing in RGB phosphors. There have been a large number of reports on the research of single-phase phosphors, involving a variety of material systems. According to the principle of luminescence, it can be simply divided into three groups: single ion doped system, multi-ion doped system and other systems which do not rely on rare earth ion to light. This paper reviews the research progress of single-matrix WLEDs phosphors, and points out the problems in their development, and forecasts the future development trend.

Key words: WLEDs, single phase, white light emitting phosphor, review

中图分类号:

TQ174

曹逊, 曹翠翠, 孙光耀, 金平实. 单基质白光LED荧光粉研究进展[J]. 无机材料学报, 2019, 34(11): 1145-1155.

CAO Xun, CAO Cui-Cui, SUN Guang-Yao, JIN Ping-Shi. Recent Progress of Single-phase White Light-emitting Diodes Phosphors[J]. Journal of Inorganic Materials, 2019, 34(11): 1145-1155.

图/表 16

图1 白光LED的发展

Fig. 1 Development of WLED (a) InGaN蓝光芯片/YAG:Ce黄色荧光粉白光LED; (b) RGB混合荧光粉白光LED; (c)单基质白光LED[4] (a) blue light emitting InGaN chips/YAG:Ce yellow light emitting phosphor WLED; (b) WLED based on red-green-blue (RGB) emitting color phosphors; (c) WLED based on single-phase phosphor[4,5,6]

图2 不同烧结温度(a)和不同Eu2+掺杂浓度下(b)的CaSrSiO4:Eu2+发射光谱图[22]

Fig. 2 PL spectra of CaSrSiO4:Eu2+ phosphors sintered at different temperatures (a) and fabricated with different Eu2+ concentrations (b)[22]

图3 400 nm GaN芯片与Ca1-xSr1-xSiO4:2xEu2+组装成LED后的发射光谱(a)和CIE色度图(b), 及其白光LED照片(插图)[22]

Fig. 3 EL spectra (a) of the white LED fabricated by using phosphors and 400 nm GaN-based LED chips, CIE (x, y) chromaticity diagram (b) with insets showing digital images of the fabricated white LED[22]

图4 (a)合成的Ba3Y1.3Eu0.7B6O15荧光体(λem= 593 nm和λex= 393 nm)在室温下的PLE和PL光谱, (b)Ba3Y2-xEuxB6O15(x = 0.1, 0.3, 0.5, 0.6, 0.7, 0.9和1.0)荧光粉的PL光谱, 及其PL强度(593 nm)随Eu3 +浓度的变化(插图)[23]

Fig. 4 (a) PLE and PL spectra of as-synthesized Ba3Y1.3Eu0.7B6O15 phosphors (λem=?593?nm and λex=?393?nm) at room temperature, (b) PL spectra of Ba3Y2-xEuxB6O15 (x?=?0.1, 0.3, 0.5, 0.6, 0.7, 0.9 and 1.0) phosphors with the inset illustrating the variation of the PL intensity (593?nm) on the concentration of Eu3+[23]

图5 具有不同Dy3 +掺杂浓度的CYAO磷光体的发射光谱(a)和CIE色度图(b)[24]

Fig. 5 Emission spectra (a) and CIE chromaticity diagram (b) of CYAO phosphors with different Dy3+ doping concentrations[24]

图6 CaYAl3O7荧光粉的能量转移图[24]

Fig. 6 Energy transfer diagram of CaYAl3O7 phosphors[24]

表1 单离子掺杂单基质白光荧光材料总结

Table 1 Summary of single activator ion doped systems for single-phase white-emitting phosphors

Phosphor	UV/nm	Emission	CIE(x, y)	Ref.
BaSrMg(PO₄)₂: Eu²⁺	385	460 nm, 550 nm	(0.29, 0.35)	[25]
Sr₃MgSi₂O₈: Eu²⁺	375	470 nm, 570 nm	(0.32, 0.33)	[26]
LaOF: Eu³⁺	274	All the emissions from Eu³⁺	(0.29, 0.34)	[27]
NaYF₄: Eu³⁺	397	⁵D_J-⁷F_J_’(J,J’=0,1,2,3,4)	(0.29, 0.33)	[28]
CaIn₂O₄: Eu³⁺	397	-	(0.32, 0.32)	[29]
BaY₂ZnO₅: Dy³⁺	355/351	489 nm, 579 nm	(0.32, 0.39)	[30]

图7 CNPO:0.01Eu2+的激发剂发射光谱[33]

Fig. 7 Emission and excitation spectra of CNPO:0.01Eu2+ phosphor[33]

图8 CNPO:0.01Eu2+, nMn2+(n = 0, 0.1, 0.2, 0.4) 的发射光谱, 激发波长分别为276 (a), 320 (b)和355 nm (c); (d) 365 nm 紫外灯照射下的荧光粉(下面一行)、日光下的荧光粉(上面一行)的照片, 其中的1, 2, 3, 4分别对应n=0, 0.1, 0.2, 0.4[33]

Fig. 8 PL spectra of the CNPO:0.01Eu2+, nMn2+(n = 0, 0.1, 0.2, and 0.4) under the excitations at 276 (a), 320 (b), and 355 nm (c), respectively; The photos of the phosphors (d) excited by 365 nm UV lamp (bottom row), and photos obtained in daylight environment (upper row). The photos 1-4 correspond to n=0, 0.1, 0.2, and 0.4, respectively[33]

表2 多离子掺杂单基质白光荧光材料

Table 2 Summary of representative multi-ion doped single-phased white-emitting phosphors

Representative examples	Excitation/nm	Emission	CIE(x,y)	Ref.
Ca₉Gd(PO₄)₇: Eu²⁺, Mn²⁺	380	Eu²⁺: blue-greenish emission band (peaking at 494 nm) + Mn²⁺: red emission band (peaking at 652 nm)	(0.326, 0.328)	[34]
CaAl₂Si₂O₈: Eu²⁺, Mn²⁺	354	Eu²⁺: a broad band centered at 425 nm + Mn²⁺: a broad band centered at 568 nm	(0.33, 0.31)	[35]
MgY₄Si₃O₁₃: Ce³⁺, Mn²⁺	328	Ce³⁺: an asymmetric broad band peaking at 455 nm + Mn²⁺: orange-red emission band at 587 nm	(0.36, 0.26)	[36]
Ca₃Sc₂Si₃O₁₂: Ce³⁺, Mn²⁺, Y³⁺	450	Ce³⁺: a green emission band peaked at 505 nm + Mn²⁺: a yellow band at around 574 nm and a red band at around 680 nm	(0.30, 0.33)	[37]
Sr₂SiO₄: Ce³⁺, Eu²⁺	354	Ce³⁺: an asymmetric blue emission + Eu²⁺: a broad band covering the blue-green to yellow region	-	[38]
Sr₃B₂O₆: Ce³⁺, Eu²⁺	351	Ce³⁺: a broad asymmetric blue emission band centering at 434 nm + Eu²⁺: a broad yellow orange emission band centering at 574 nm	(0.31, 0.24)	[39]
Ca₄Y₆(SiO₄)₆O: Ce³⁺, Tb³⁺	352	Ce³⁺: a blue band centered at 421 nm + Tb³⁺: characteristic emission lines ranging from 470 to 650 nm with yellow-greenish emission	(0.278, 0.353)	[40]
Ca₂Al₂SiO₇: Ce³⁺, Tb³⁺	352	Ce³⁺: a blue band centered at 419 nm + Tb³⁺: characteristic emission lines ranging from 470 to 650 nm with yellow-greenish emission	(0.316, 0.336)	[41]
Sr₂Al₂SiO₇: Ce³⁺, Dy³⁺	335	Ce³⁺: a blue emission band at 408 nm + Dy³⁺: the emission bands at 491 nm and 573 nm	-	[42]
12CaO·7Al₂O₃: Ce³⁺, Dy³⁺	362	Ce³⁺: a broad band centered at 430 nm + Dy³⁺: two narrow bands centered at 476 nm and 576 nm	(0.324, 0.323)	[43]

图9 不同电流下单相双激发的Mn2+掺杂Zn-Cu-In-S纳米晶材料的发光光谱图[57]

Fig. 9 Electroluminescence spectra of the WLED operated under various currents of 20 to 60 mA. Inset: the variation in CIE chromaticity coordinates of the WLED under various currents[57]

图10 AVO3结构示意图[58]

Fig. 10 Schematic crystal structure of AVO3[58]

表3 AVO3(A=K, Ru, Cs)和M3V2O8 (M=Mg, Zn)的光学性质[60]

Table 3 Luminescence property of AVO3 (A=K, Ru, Cs) and M3V2O8 (M=Mg, Zn)[60]

Sample	KVO₃	RbVO₃	CsVO₃	Mg₃V₂O₈	Zn₃V₂O₈
η/%	4	79	87	6	52
CIE(x, y)	0.362, 0.453	0.316, 0.424	0.306, 0.418	0.449, 0.475	0.432, 0.478
CCT/K	4859	5993	6334	3318	3583

表4 不同AVO3荧光粉的光学性能[63]

Table 4 Optical property of heterogeneous AVO3[63]

AVO₃ phase	PLE peak/nm	PL peak/nm	FWHM/nm	CIE(x, y)	CCT/K
CsVO₃(W)	356	487	151	(0.2421, 0.3283)	12050
CsVO₃(Y)	342	503	138	(0.2671, 0.3855)	8444
RbVO₃(W)	357	491	149	(0.2462, 0.3379)	11152
RbVO₃(R)	342	510	149	(0.2797, 0.3960)	7700

图11 (a)365 nm紫外光激发下的CsPbX3(X = Cl, Br, I)无机钙钛矿量子点溶液及薄膜样品, (b)吸收曲线, (c)不同组分的发射光谱[65]

Fig. 11 Controllable photoluminescence (a) Optical images of solution and film samples with different bandgaps under a 365 nm UV lamp; (b) Optical absorption; (c) Photoluminescence spectra of IPQDs with different composition[65]

表5 各类单基质白光荧光粉的优缺点

Table 5 Advantages and disadvantages of single-phase WLEDs phosphors

Phosphors		Advantages	Disadvantages
Rare earth ion doped system	Single activator ion doped systems	High quantum conversion efficiency; wide emission spectrum range	Low color rendering index; high price; harmful to the environment
Rare earth ion doped system	Multi-ions co-doping systems
Rare earth ion free systems	Semiconductor nanocrystal	Large absorption coefficient; wide excitation and emission band; high quantum yield; easy to be combined with packaging materials	Expensive raw materials; complex synthesis process; poor stability
	Vanadate	High luminous efficiency; low preparation temperature	High color temperature; low intensity in red region
	Perovskite	Optical band gap adjustable; high quantum conversion efficiency	Pollution from soluble heavy metal Pb

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