白光LED用Ce,Re∶YAG单晶的研究进展

通过Ce,Re∶YAG单晶替代荧光粉与蓝光芯片产生白光是近几年发展起来的新方法.本文对Ce,Re∶YAG单晶的主要制备方法进行了说明.综述了目前国内外用于白光LED的Ce∶YAG系列单晶的研究进展,并对其研究成果进行了分析,给出了部分具有代表性的荧光光谱图.最后对晶片式白光LED的发展前景进行了展望.     

白光发光二极管用荧光粉的研究进展

白光LED被称作第四代照明光源,有着庞大的市场。文章主要介绍了白光LED用荧光粉,特别是紫外/近紫外光激发的白光LED用荧光粉的技术现状,并指出今后的发展需要解决的问题。     

白光LED用荧光粉制备方法的研究与分析

白光LED被称作第四代照明光源,有着庞大的市场。本文综述了国内外白光LED用荧光粉的几种制备方法,总结了它们的优缺点,并指出今后的发展需要解决的问题。     

LED用稀土Eu掺杂硅酸盐基荧光粉的研究进展

由于硅酸盐为基体的光转换材料具有原料来源丰富、工艺适应性广泛及晶体结构稳定性较高等特点,目前已成为白光发光二极管(light-emitting diode,LED)用荧光粉的研究重点之一。本文综述了近年来国内外硅酸盐基稀土荧光粉材料的研究进展,对硅酸盐基稀土荧光粉的材料体系、发光机理及发光特性的改进方面进行了分析与探讨。通过比较固相反应法和溶胶-凝胶法两种不同制备方法的优缺点,阐述了不同制备方法对白光LED质量的影响,并对硅酸盐基荧光粉的发展趋势和应用前景作了简要展望。     

白光LED用Ce，Sm共掺杂YAG单晶荧光材料的光谱性能

对白光发光二极管（light-emitting diode,LED）用Y3Al5O12（YAG）单晶荧光材料的制备和光谱性能进行了研究。采用提拉法生长了白光LED用Ce：YAG及Sm,Ce：YAG晶体,并通过吸收光谱、激发光谱和发射光谱等对晶体的光谱特性进行表征。结果表明：Ce：YAG单晶作为荧光材料被发射波长460 ...     

白光LED用新型红色荧光粉的组成与发光性能的关系

白光LED有望发展成为新一代绿色照明光源.荧光粉作为配套材料,其性能优劣直接影响白光LED的发光效率、亮度以及显色性等.高效红色荧光粉已经成为白光LED发展的瓶颈.概述了Eu3+激活的钨/钼酸盐、氧化钇铋和钛酸盐,Sm3+激活的锌酸锶,Pr3+和Bi3+共激活的钛酸钙,Eu2+激活的氮化物,Ce3+激活的硅锗酸盐石榴石以及Mn4+激活的多铝酸钙和Mn2+激活的硫氧化锌钙等白光LED用新型红色荧光粉的发光性能的研究进展;着重分析了它们的组成变化对荧光性能的影响;并对今后的研究提出了一些设想.     

聚碳酸酯稀土荧光树脂白光LED的研制

文章通过点胶法和荧光树脂法制备了两种白光LED,对其色温、显色指数及光效等性能进行了对比研究。结果表明:挤出加工过程对0754荧光粉的晶体结构破坏明显,从而导致荧光树脂法白光LED光效低于点胶法白光LED光效,但对YAG-5荧光粉晶体结构影响不大,荧光粉在荧光树脂中的良好分布明显提高了白光LED的综合性能。荧光粉浓度为30%,荧光树脂厚度0.2 mm时,白光LED光效最大;荧光树脂白光LED工作5000 h后仍能保持较高光效,耐老化性能良好。     

白光LED用新型荧光粉的探索

白光LED具有效率高、寿命长、响应快、安全、环保等优点,被誉为继白炽灯、荧光灯和高强度气体放电灯后的“第四代照明光源”.白光LED用荧光材料的制备及其发光性能的研究已成为半导体照明领域的一个热点.本文主要从蓝光芯片激发和近紫外光芯片激发的角度分别介绍了钼酸盐红色荧光粉和单一基质白光荧光粉的研究概况.     

阳离子置换在白光LED灯用荧光粉中运用的研究进展

根据目前LED实现白光的两种主流方式:近紫光LED芯片+红/绿/蓝三基色荧光粉和蓝光LED芯片+黄色荧光粉(或+绿色/红色荧光粉),本文重点从黄色荧光粉、绿色荧光粉、红色荧光粉及蓝色荧光粉四个方面综述了利用阳离子置换实现对白光LED灯用荧光粉发光性能改善的研究进展,并对利用该方法对荧光粉的发光性能改善的研究趋势进行了展望。     

白光LED用红色荧光粉的制备工艺研究进展

LED(light emitting diode,发光二极管)以其自身所具备的省电、节能、环保、寿命长、亮度高等优势成为各行各业和老百姓生活中的新宠。其中,白色LED的使用率和使用量最高。红色荧光粉作为生产白光LED过程中比较关键的发光材料,其质量的高低对于优化白光LED的发光性能具有重要的意义。以白光LED作为基础,结合红色荧光粉的制备过程,系统地阐述了白光LED用红色荧光粉的制备工艺研究进展,以此来探究白光LED性能的提升方法。     

高显色白光LED用YAG：Ce^3＋，Ln^3＋荧光粉的研究进展

综述了YAG：Ce荧光粉的制备方法,着重介绍了高显色白光LED用YAG：Ce^3＋,Ln^3＋（Ln=Sm,Pr,Gd,Tb）荧光粉的最新研究进展和发光性能。YAG：Ce^3＋,Ln^3＋荧光粉的发射谱带发生红移,或在红光区增加尖锐的红光发射峰,从而提高了白光LED的显色性能。     

Particle Size Effect on the Packaging Performance of YAG:Ce Phosphors in White LEDs

The synthesis of cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor of different sizes with uniform size distribution was carried out using solid-state reaction followed by grinding and sieving method. The effect of particle size distribution of YAG:Ce phosphors on the photoluminescence (PL) properties was investigated. The results demonstrate that the uniform size distribution and particle size affects the packaging performance in white light emitting diode (LED) applications. The YAG:Ce phosphors with different particle sizes were packaged in white LEDs using different amounts of each phosphors in order to get similar efficiency as that of commercially available YAG:Ce phosphors. It was observed that minimum amount of phosphor material is required for smaller particle size for getting the similar efficiency as that exhibited by commercially available YAG:Ce phosphors. The results are particularly interesting in view of reducing the cost of current LEDs by lowering the amount of phosphors without compromising the efficiencies of final LED package. A systematic study of YAG:Ce phosphors on the packing performance in white LEDs is reported.     

SPS烧结制备新型荧光玻璃材料

以实验室自制SiO2粉体和商用Ce∶YAG荧光粉为玻璃原料,采用放电等离子体烧结（SPS）技术,在1 200℃保温2 min烧结得到有望用于白光LED封装的Ce∶YAG荧光玻璃。用X射线衍射仪（XRD）、荧光光谱（PL）等方法对制备获得的荧光玻璃样品进行表征。结果显示,烧结并没有破坏Ce∶YAG荧光粉的晶体结构,且荧光玻璃主体相仍为玻璃体,该荧光玻璃在460nm具有强吸收峰,在此波长激发下发射出530 nm左右的黄光。研究结果表明,本实验制备的Ce∶YAG荧光玻璃是一种具有重要应用前景的LED封装用新型荧光材料。     

Combustion synthesis of multicomponent ceramic phosphors for solid state lighting

About 50% of the world’s need for lighting is provided by artificial lighting. For over the last decade, the world has witnessed rapid shift from conventional Hg-based lighting to LED-based solid state lighting (SSL). SSL technology extensively uses YAG:Ce³⁺ phosphor for production of white light emitting devices (LEDs). Part of the blue light from the (In,Ga)N LED chip is absorbed by a thin layer of Ce³⁺-doped YAG and is converted into yellow light. The combination of blue and yellow gives a bright white light source with an overall energy efficiency exceeding that of a compact fluorescent lamp. Several soft chemical routes have been explored for synthesis of YAG but were discarded due to their complex nature, high cost for the industrialization, phase impure materials, etc. In this paper we describe rapid one-step modified combustion synthesis of YAG:Ce³⁺ and related phosphors carried out at 500°C using a mixed fuel. Photoluminescence spectra of YAG:Ce³⁺ and LED prepared thereof are comparable with those of commercial phosphors.     

Warm white light-emitting diodes using organic–inorganic halide perovskite materials coated YAG:Ce3+ phosphors

This work reports warm white light-emitting diodes (WLEDs) using organic–inorganic halide perovskite materials coated YAG:Ce³⁺ phosphors by a liquid phase synthesis method. The perovskite MAPbBr_3?xI_x-coated YAG:Ce³⁺ phosphors have more red light contribution than YAG:Ce³⁺ phosphors without the perovskite coating. The chromaticity coordinate of white LED with YAG:Ce³⁺ remote phosphor is (x = 0.3134, y = 0.3497) 6359. However, those of MAPbBr_2.5I_0.5 and MAPbBr_2.0I_1.0-coated YAG:Ce³⁺ remote phosphor shift to (x = 0.4220, y = 0.3725) 2908 and (x = 0.4067, y = 0.4028) 3525, respectively. The colors of perovskite-coated samples are more red and warm. Therefore, the perovskite-coated YAG:Ce³⁺ method is useful for warm WLED.     

Glass-ceramic phosphors for solid state lighting: A review

Solid state lighting, including phosphor converted light-emitting diodes (LEDs) and laser diodes (LDs), have released high demand to develop thermally stable phosphors. For this purpose, inorganic glass-ceramics (GCs) embedded with phosphor particles can act as competitive candidates. They are superior to traditional phosphors or resin/silica composites through successfully overcoming thermal aging and color temperature drifting problems and simultaneously maintaining high luminescent efficiencies. Inorganic GC phosphors can be classified into devitrified glass-ceramics, PiG (Phosphor-in-Glass) and sintered glass-ceramics. This review summarized the recent progress on LED/LD GC phosphors from the aspects of design principles, synthesis methods, microstructure-property relationships and their application studies. In addition, some challenging issues (e.g., crystallization behavior of luminous phase in glass, corrosion behavior of phosphor by glass matrix) are also discussed in detail. Significant issues of glass-ceramics packed LED/LD, such as luminescence efficiency, chromaticity, correlated color temperature and color gamut, are sorted out as well. Potential research directions are further suggested for not only developing new glass-ceramic phosphors but feeding upon various practical application.     

Residual porosity and optical properties of spark plasma sintered transparent polycrystalline cerium-doped YAG

Transparent cerium-doped yttrium aluminum garnet (Ce:YAG) phosphors are promising candidates for high-power white light emitting diode applications. In the present study, Ce:YAG powder was synthesized by a co-precipitation method and highly transparent ceramics were fabricated by spark plasma sintering. The effects of temperature and pressure, as well as post-sintering treatments (annealing or hot isostatic pressing), on residual porosity were studied by electron and confocal laser microscopy. Correlation between residual porosity characteristics (pore size and volume fraction) and optical properties (in-line transmittance and photoluminescence intensity) of the luminescent transparent ceramics was established.     

Design of the YAG:Ce3+ phosphor in tellurite-germanate glass with high luminous efficiency for laser lighting

The main focus of laser lighting research has been on perfectly combining fluorescent conversion materials with laser light sources to improve luminous efficiency (LE). In this paper, the high refractive index, high transmittance and low sintering temperature of tellurite glass is combined with the thermal stability and mechanical strength of germanate glass，which is innovatively used as a matrix for phosphor-in-glass (PiG). The use of high valent ions as modifiers reduces the diffusion and mobility of ions to reduce the erosion of phosphors and protect the luminescent performance of phosphors. By changing Ge/Te ratio, the glass maintains 80% transmittance, and the refractive index decreases from 1.97 to 1.83 matching that of the YAG phosphor. The increase in GeO₂ improves the thermal stability and mechanical strength of the glass, thereby improving the fluorescence intensity (approximately 1.6%) at 473 K and the luminous flux by up to 12.8%. The best PiG sample had a LE of 230 lm/W and excellent internal quantum efficiency (IQE) of 85.3%, achieving high levels of luminescence. Adding different phosphor contents can achieve the role of adjusting the correlated color temperature (4500–6000 K), and the color coordinates (0.322, 0.330) are close to the ideal white light. These results show that tellurite-germanate glass can be used as a good carrier for fluorescence conversion materials, which brings a new direction for the exploration of glass matrix.     

铈掺杂玻璃陶瓷的绝对光谱功率分布与荧光量子产率

采用直径10in积分球结合CCD(Charge Coupled Device)探测器测试系统,在蓝色半导体发光二极管激发下,对Ce3 掺杂的Y3Al5O12(YAG)玻璃陶瓷的荧光光谱进行表征,实现了以荧光发射特性绝对评价为目的的绝对光谱功率分布测定,为白色LED(Light Emitting Diode)荧光材料发射特性的精确测定提供了一种准确方法。荧光测试系统经标准卤素灯定标,辅助卤素灯校正积分球内环境变化,解析出样品发光的绝对光谱功率分布,并进一步计算出光量子数分布,求得荧光量子产率。实验结果表明,YAG高效玻璃陶瓷片的荧光量子产率高达33.7%,为新型高效LED照明发光材料的研制提供了新的标准和比照。