《硅酸盐学报》：玻璃及无机非晶态固体——光LED 用铕离子掺杂硼铋锌红光玻璃的制备与性能

夏李斌 1,2，叶信宇 2，潘锡翔 2，游维雄 1，肖青辉 1，李子成 1
 (1. 江西理工大学材料科学与工程学院，江西 赣州 341000；2. 江西理工大学冶金与工程学院，江西 赣州 341000)

摘  要：用熔融冷却法制备铕离子掺杂硼铋锌透明红光玻璃(BBZE)。研究了折射率、密度、摩尔体积、氧离子堆积密度、铕离子体积浓度等物理性质，分析了玻璃的结构、光学性质和热稳定性。结果表明，4%(摩尔分数)Eu³⁺掺杂时达到最佳值，在 465 nm 激发下，613 nm 处发射强烈红光。玻璃结构中包括[BO₃]、[BiO₃]和少量的[BO₄]组分单元，[BO₃]组成的六圆环结构只存在于铕离子掺杂量高(6%)的玻璃样品中。玻璃呈非晶态，随着 Eu³⁺的升高，玻璃的结构变得更稳定。玻璃中析晶点与玻璃转化点的差值较大，表明其具有良好的热稳定性。这种具有低熔点的 BBZE 玻璃有望成为用 YAG–PIG工艺制备白光 LED 玻 璃的良好基质。

关键词：发光材料；红光发射；硼铋玻璃；折射率

中图分类号：TQ128+.5，TQ135.3    文献标志码：A   

文章编号：0454–5648(2017)03–0410–06

网络出版时间：2017–02–20  10:02:11       

网络出版地址：

http://www.cnki.net/kcms/detail/11.2310.TQ.20170220.1002.013.html

收稿日期：2016–06–23。   

修订日期：2016–09–08。

基金项目：

江西省基金(GJJ150636，2014ZBAB206006)，

江西理工大学优秀博士基金 (YB2016008)资助。

第一作者：夏李斌(1981—)，男，博士研究生。

通信作者：叶信宇(1980—)，男，副教授。

前言

In the last few decades, white lightemitting diodes (WLEDs) have been widely used as a new type of luminescencesource for general illumination, indicators,In the lastfew decades, white light emitting diodes (WLEDs) have been widely used as a newtype of luminescence source for general illumination, indicators,backlights, and automobile headlights due to their excellent performance,including their long service life, energy saving abilities, and environmentalfriendliness^[1–2]. The existing commercial WLEDs consist of an InGaNblue–emitting chip, a YAG:Ce yellow–emitting phosphor and a silicone or epoxyresin binder. However, three disadvantages exist when using these materials topack the WLEDs^[3–5]. First, silicone and epoxy resin are easily ageddue to their poor heat dispersion abilities, which could shorten the servicelife of the WLED. Second, the interface of the phosphor and the binder couldcreate a yellow or black spot after long–term service, which reduces theluminous efficiency. Last but not least, the existing commercial WLEDs have alittle red light, which results in a low color rendering.

In recent years, luminescent glasses andglass ceramics have attracted much attention to produce high-quality WLEDs. Twoapproaches can be used for the preparation of luminescent glasses and glassceramics. One approach is to embed (Ca, Sr) SiAlON:Eu²⁺ red phosphorinto a glass matrix with a high melting point to form glass via thephosphor-in-glass (PiG) approach, which becomes increasingly popular. However,it is difficult for the practical applications of this method due to itsrelatively expensive price and light absorbing action^[6–9]. Otherapproach is to dope Pr³⁺, Sm3+, or Eu³⁺ into bismuth,tellurium or antimony glass^[5,10–13]. Due to its low melting point,high refractive index and good rare earth solubility, heavy metal glasses havebeen widely investigated, in which red emission comes from the glasses.However, little systematic studies on the properties of these glasses (i.e.,the refractive index, structure, optical properties, and thermal stability) forapplication in PiG–YAG–WLEDs (i.e.,YAG phosphor embedded in glasses for whiteLEDs) have been reported.

In this paper, zinc bismuth boratetransparent glasses doped with Eu³⁺ (BBZE) were investigated. Boricanhydride was used as a primary raw material to form the glass frame, whichensured the low melting point of the matrix. Bi₂O₃ wasused as a network former and a network modifier to make the glass structurecompact. The thermostability and chemical resistance could be promoted byadding ZnO. Eu³⁺ was used as a luminescence activator. The glassescould be effectively excited by an InGaN blue chip to produce red light. Thephysical properties, structure, optical properties and thermal stability of theBBZE glasses were investigated. The BBZE glasses could have potentialapplications in the PiG–YAG–WLEDs.

结论

Zinc bismuth borate transparent glassesdoped with various Eu³⁺ concentrations (BBZE) were prepared by arapid melt quenching technique. The general physical parameters (i.e., density,refractive index, molar volume, etc.) were investigated. The density andrefractive index of the BBZE glasses increased when Eu³⁺ dopingincreased from 0 to 6%, which could be due to the higher molecular weight andrefractive index of Eu₂O₃ relative to B₂O₃.The refractive indices were in the range of 1.827–1.866, which were well suitedfor YAG glasses. These experimental results indicated that Eu₂O₃acted as a network modifier and produced bridging oxygens to B₂O₃.Consequently, the glass structures become more compact because the planartriangular [BO₃] units converted into more stable tetrahedral [BO₄]units. The BBZE glass doped with 4% Eu³⁺ was highly excited at 465nm, and the most intense visible red emission was located at 613 nm. [BO₃]and [BiO₃] units, as well as a few [BO₄] units, appearedin the BBZE glasses; however, six–membered rings of [BO₃] occurredin only the highly Eu³⁺-doped (6%) samples. These glasses all werein the amorphous state. In addition, the BBZE glass doped with 4% Eu³⁺had a large Tc–Tg, a low melting temperature and an increased thermalstability, which favored the PiG–YAG process of WLEDs. Zinc bismuth borate transparentglass doped with 4% Eu³⁺ could be a potential candidate as a colorconverter for PiG–YAG–WLEDs.

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