【作者】 曹美玲；

【导师】 程圭芳；

【作者基本信息】 华东师范大学 ， 分析化学， 2009， 硕士

【摘要】 随着发光材料的研发和半导体制作工艺的改进,白光半导体发光二极管(LED)的发展非常迅速,它已经趋向取代传统的照明,由于白光LED具有的长寿命、无污染、低功耗的特性,未来LED还将逐步替代荧光灯、白炽灯成为下一代绿色照明光源。本论文首先简单介绍LED的概念、特点、提出了现阶段白光LED存在的问题:即发光效率的提高和导热问题的解决。针对白光LED所存在的问题,提出新型光热复合材料——量子点/荧光粉复合材料的合成及复合导热材料的开发。1、以氯化镉、硒氢化钠为前驱体,采用超声水浴法制备水溶性CdSe量子点并使用紫外吸收光谱与荧光光谱、透射电子显微镜等测试其光学性质和形貌结构。研究结果表明制得的量子点尺寸为2-3nm,通过改变反应时间、反应温度、反应溶液的pH值、稳定剂的浓度及反应物的摩尔配比等条件,可以得到不同发光波长和强度的CdSe量子点。最终将量子点发光材料掺杂到LED荧光粉中。制备高发光效率的复合发光材料的研究有待进一步的开展。2、散热的研究。由于PN结温度的上升会使发光复合的几率下降,发光二极管的亮度就会下降,寿命和输出光通也会随着温度的升高而下降,如果PN结产生的热量能尽快的散发出去,不仅能提高产品的发光效率,同时也能提高产品的可靠性和寿命。因此研究一种高导热复合材料可以大大提高LED的工作性能。更多还原

【Abstract】 With the development of material and the innovation of semiconductor manufacture technology,the rapid development of white LEDs is more and more significant.White LEDs have tended to replace the traditional lighting,owing to their long life,non-polluting,low-power performance.LEDs will open a new era in "green lighting".The paper first briefly introduces the concept and characteristics of LEDs. Currently,white LEDs are confronted with two problems of low luminescent efficiency and bad heat dissipation.To solve the above problems,the investigation in novel luminescent and thermal composite materials is performed in this paper.1、Water-soluble cadmium selenide（CdSe） QDs by employing CdCl₂ and NaHSe as precursors were synthesized in alkaline aqueous solution by ultrasonic method.Their structure and optical properties were studied by photoluminescence spectroscopy,UV-Vis spectra and transmission electron microscope.The result showed that the size of CdSe QDs was about 2-3nm and their optical properties such as the wavelength and intensity of photominescence were dependent on the reaction time,the growth temperature,the pH value,the concentration of stabilizing agent and reactants etc.Eventually quantum dots were doped into the LED light-emitting phosphors and further study is to be carried out.2、Another aspect is the heat dissipation.In general,the cooler the environment,the higher an LED’s light output will be.Higher temperatures generally reduce light output and LED’s lifetime.If the heat within the junction is dissipated by convection and conduction,the actual lifetime and the efficiency of LED would be increased.Nano-composite materials with high thermal conductivity have been explored to enhance the LED performance.更多还原