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摘要LED（发光二极管）自从上世纪九十年代其问世的一刻起就备受瞩目。相较传统的白炽灯，LED在光电效率、寿命、低电压、节能环保等方面都具有相当优势。随着技术的日渐成熟，以及各国政府部门的政策推广，使得LED在应用端取得了较快的发展。在生活中诸如显示屏、交通灯、背光照明等等应用端，LED以及变得十分普及。从飞利浦、科锐、通用照明等巨头在照明界的一系列业务举措，以及小米、华为等品牌在智能LED照明领域的投入，也让市场看到了新的增长点和突破点，综上足以说明LED的研究及应用热在未来仍将是一大热点。其中白光LED因其广阔的市场需求，成为近几年来光电子领域研究的一大热门。白光LED及组合光源具有许多优点：光效可以达到200lm/W以上、固体化、体积小、寿命长（万小时）、抗振、不易破损、启动响应时间快（ns）、耗电小、无公害（无汞）等。[1][2]荧光粉对白光LED光效和色度的表现起着至关重要的作用。荧光粉的选用可以是高效的无机或有机荧光粉或两者的结合。目前市场上主导的方案为由蓝色InGaN LED芯片和可被蓝光有效激发的发黄光的铈(Ce)激活的稀土石榴石荧光粉（Y1Gd）3(AlGa)5O12荧光粉有机结合实现发白光LED。[3][4]但是，这种白光LED所发射出的光谱中，红色组分的光谱所占比例明显不足，想获得高显色指数且低色温的暖白光LED较难实现，是使之商品化的瓶颈之一。目前主流的趋势是从蓝光黄粉LED，逐渐向发出红色光和绿色光的荧光粉过渡。而能符合应用要求的高性能、低成本的红色荧光粉仍然是十分缺乏的。资料表明，对单一基质，利用稀土离子共掺杂来实现白光发光的研究不在少数。例如使用Eu2+/Ce3+，Tb3+，Mn2+共掺杂或者Dy3+,Eu3+掺杂。然而这种通过调制激活离子浓度来实现白光的方法，其发光效率低，热稳定性差，当工作温度升高，色坐标存在漂移的问题；对单掺杂的荧光粉来说，其白色光的纯度差，发光亮度也不高，以上都是亟待解决改进的技术难点。本文介绍了荧光粉，常见的制备方法和其发光机理。使用高温固相法，添加Li2CO3作为助溶剂，以合成稀土离子掺杂荧光粉Eu3+：（Y1-xGdx）2SiO5。通过在相同煅烧温度和煅烧时间下，研究合适的Y/Gd配比，比较不同Eu的掺杂浓度对发光性能的影响。采用XRD对样品进行晶体结构分析，采用荧光分光光度法测得样品的发射和激发光谱，为研究性能更全面的白光用LED稀土荧光红粉提供理论依据。27952
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毕业论文关键词：稀土掺杂；高温固相法；红光荧光粉；白光LED
AbstractLED (light emitting diode) since the nineties of last century came the moment of its high-profile. Compared to traditional incandescent, LED photoelectric efficiency, life, low voltage, energy saving and environmental protection have substantial advantages. As the technology matures, and policies to promote the national government departments, making the LED in the application side has achieved rapid development. In life, such as displays, traffic lights, backlighting, and so the application side, LED and it became very popular. From Philips, Cree, general lighting and other giants in a series of business initiatives lighting industry, as well as millet, Huawei and other brands investment in intelligent LED lighting field, but also allow the market to see a new growth point and breakthrough point, the mechanized suffice Research and Application of Thermal LED in the future will continue to be a hot topic.Which because of its vast white LED market demand in recent years, photonics has become a hot area of research. And a combination of white LED light source has many advantages: luminous efficiency can reach 200lm / W or more, solidified, small size, long life (ten thousand hours), vibration, not damaged, start fast response time (ns), low power consumption, no pollution (mercury-free) and so on.Phosphor white LED luminous efficiency and color performance plays a vital role. Selection phosphor can be efficiently combined inorganic or organic phosphor or both. Currently on the market-led solutions by blue InGaN LED chips and can be efficiently excited by blue light yellow-cerium (Ce) activated rare earth garnet phosphors (Y1Gd) 3 (AlGa) 5O12 combine to achieve white light emitting phosphor LED. However, the white light emitted by the LED spectrum, the spectral components of the proportion of red is obviously insufficient, to obtain a high color rendering index and low color temperature warm white LED is more difficult to achieve, it is to make the commercialization bottleneck . The current mainstream trends gluten from the blue LED, and gradually to emit red light and green light phosphor transition. Can meet the application requirements of high-performance, low-cost red phosphor is still very lacking.Data show that a single matrix using a total rare earth ions to achieve white light a few doping research. For example, using Eu2 + / Ce3 +, Tb3 +, Mn2 + co-doped or Dy3 +, Eu3 + doped. However, this activation by modulating the ion concentration to achieve white light method, the luminous efficiency is low, poor thermal stability, when the temperature rises, the color coordinates presence of drift problem; for a single doping phosphors, its white light poor purity, brightness is not high, these are to be solved to improve the technical difficulties. This article describes the phosphor, a common preparation method and its light emission mechanism. Use high-temperature solid-phase method, adding Li2CO3 as a co-solvent to synthesize rare earth ion-doped phosphor Eu3 + :( Y1-xGdx) 2SiO5. By the same calcination temperature and calcination time, on an appropriate Y / Gd ratio, comparing different Eu doping concentration on luminescent properties. The samples were characterized by XRD crystal structure analysis, as measured by fluorescence emission spectrophotometry and excitation spectra of the sample for the study of the performance of a more comprehensive use of white LED rare earth fluorescent Pink provide a theoretical basis.