毕业论文移动版

摘要：白光发光二极管(LED)是21世纪将替代荧光灯和白炽灯的新一代固体照明光源，具有体积小、寿命长、无辐射、无汞污染、低能耗、高效率等一系列优点。目前，获得白光LED的主要方法是荧光粉转换法，即将LED芯片和稀土荧光粉材料组合形成白光，其中荧光粉起着重要的作用，而研究能被近紫外光激发的荧光粉材料已成为国际热点。本论文研究的荧光粉以硅酸盐为基质材料，通过掺杂不同激活剂离子产生蓝色、红色和红橙色发光，具体如下。

通过高温固相法制备Na0。34Ca0。66Al1。66Si2。34O8:Eu2+/Eu3+/Sm3+ (NCAS:Eu2+/Eu3+/Sm3+)荧光粉样品。采用漫反射光谱实验确定了NCAS化合物的光学带隙为4。04eV。NCAS:2％Eu2+的激发光谱显示出从240到410nm的宽带激发，可以与近紫外LED芯片匹配。在365nm激发下，获得了375-650nm的蓝色发射，通过研究浓度猝灭发现，NCAS：2％Eu2+样品显示出最强的发光强度，而随着Eu2+浓度的增加，主发射峰发生续红移。在Eu3+/Sm3+激活的NCAS荧光粉中分别获得红色和红橙色发光，CIE色度坐标分别为（0。653,0。347）和（0。605,0。395）。上述相关研究结果表明，本论文研究的荧光粉材料NCAS：Eu2+/Eu3+/Sm3+在LED照明方面具有一定的应用潜力。95025

毕业论文关键词：荧光粉，Na0。34Ca0。66Al1。66Si2。34O8:Eu2+/Eu3+/Sm3+，LEDs，发光性质

Abstract: White light-emitting diode (LED) is a new generation of solid-state light source that will replace fluorescent lamps and incandescent lamps in the 21st century。 It has a series of advantages such as small volume, long life, no radiation, no mercury pollution, low energy consumption and high efficiency。 At present, the main method to obtain white LED is phosphor-converted method, which combines LED chip and rare earth doped phosphor materials to achieve white light, in which the phosphors play an important role。 And investigating phosphor materials that can be excited by near ultraviolet light has become an international hot spot。 In this paper, the phosphors investigated are based on the aluminosilicate, and blue, red and red-orange emissions were produced by doping different activator ions, the details are shown as follows。

Na0。34Ca0。66Al1。66Si2。34O8:Eu2+/Eu3+/Sm3+ (NCAS:Eu2+/Eu3+/Sm3+) phosphors were prepared by solid-state reaction method。 The optical bandgap of the NCAS compound was determined to be 4。04 eV experimentally。 The excitation spectrum of NCAS:2%Eu2+ shows a broad excitation band from 240 to 410 nm, which could match with the NUV LED chip。 Upon 365 nm excitation, blue emissions between 375 and 650 nm have been obtained, accompanied with a continuous red-shift for the predominated emission peaks with increasing Eu2+ concentration。 Red and red-orange emissions are gained in the Eu3+ /Sm3+ activated NCAS phosphors with the chromaticity coordinates (0。653,0。347) and (0。605,0。395) respectively。 The results of the above research show that the NCAS: Eu2 + / Eu3+ / Sm3+ phosphors in this work could have promising application in the LED lighting field。

Keyword: Phosphor, Na0。34Ca0。66Al1。66Si2。34O8:Eu2+/Eu3+/Sm3+, LEDs, Luminescent properties

目 录

一  绪论 4

1。1  白光LED的优点及实现方式 4

1。1。1  白光LED存在的问题 4

1。2  白光LED用稀土荧光粉的发光原理 4

1。2。1  稀土元素简介 4

1。2。3  稀土离子的发光机理    6

1。2。4  稀土发光材料的应用 (责任编辑：qin)