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直接发白光的有机/无机杂化半导体材料研究
Research on Organic - Inorganic Hybrid Semiconductors That Emit Direct White Light
【作者】 周美玲；
【导师】 方晓明；
【作者基本信息】 华南理工大学 ， 能源环境材料及技术， 2010， 硕士
【摘要】 白光LED直接将电转换为光,比传统光源具有更高的转换效率,有助于节约能源,减少CO2的排放,且因具有寿命长、体积小、反应快、耐冲击的优异性能而被看成是继白炽灯、荧光灯和高压气体放电灯之后第四代照明光源。Ⅱ-Ⅵ有机/无机杂化半导体综合了有机物和无机半导体的优点,具有良好的传输特性和高载流子迁移率。本论文采用溶剂热法制备出2D-[Zn2S2（ha）],在此基础上通过分别掺杂Cd,Se以及Cd和Se共掺杂,制备出一系列光学和电子性能可调节的Ⅱ-Ⅵ有机/无机杂化半导体,再将此材料应用于紫光LED,制备出直接发白光的LED。旨在利用Ⅱ-Ⅵ有机/无机杂化半导体良好的传输特性和高载流子迁移率克服目前制备白光LED的缺点,同时将Ⅱ-Ⅵ有机/无机杂化半导体的研究上升到应用阶段。以ZnCl2,S等为无机原料,正己胺为溶剂,采用溶剂热法制备出2D-[Zn2S2（ha）]及Cd和Se共掺杂的产物。考察制备工艺条件如反应时间、温度、有机物与无机物的配比等对其结构和性能的影响,确定50 ml反应釜中合成的适宜工艺条件为:温度120℃,反应时间2天,正己胺（ha）6 ml。最佳Cd和Se的单独掺杂含量分别为15 mol%和10 mol%;固定Cd含量为20 mol%和25 mol%时的最佳Se的掺杂含量分别为15 mol%和10mol %。通过XRD,UV-vis和荧光等手段分别对2D-[Zn2S2（ha）]及其掺杂产物进行结构和光学性能的表征。结果表明,各产物属于同种二维结构,通过改变掺杂的组成和含量可系统调节其光学性能。掺杂后band gap最大减小1.3 eV,荧光发光范围增大至380 -700 nm,荧光强度最大增大167.29 %,较2D-[Cd2S2（ha）]杂化材料大大增强。在450℃下煅烧30分钟之后产物二维层状结构被破坏,band gap减小,荧光强度急剧下降。
【Abstract】 White LED （Light-emitting diodes） convert electricity to light much more effectively than conventional lighting sources. They contribute to energy conservation and reduction of green house gases and offer a cleaner environment. Additionally, with the excellent performance such as long lifetime, small size, fast response and impact resistance, they have been considered to be the fourth illumination source after incandescent lamp, fluorescent lamp and gas discharge lamp.Ⅱ-Ⅵorganic - inorganic hybrid semiconductors combined the advantages of organic compounds and inorganic semiconductors so that they can provide good transmission characteristics and high carrier mobility. With the purpose of overcoming the shortages of current preparation of white LED, simultaneously rising the research ofⅡ-Ⅵorganic - inorganic hybrid semiconductors from foundation to application, 2D-[Zn2S2（ha）] has been synthesized through solvothermal reaction in this paper. Through systematically tune its optical properties simply by doping Cd and Se respectively, as well as Cd and Se co-doping, a series ofⅡ-Ⅵorganic - inorganic hybrid semiconductors that can emit direct white light have been used to produce white light LED successfully.The influence of preparation conditions such as reaction time, temperature, the ratio of organic and inorganic materials on the structure and properties was investigated. The optimal conditions for synthesis in 50 ml vessel are as follows: temperature 120℃, reaction time 2 days, solvent volume （ha） 6 ml. The best Cd and Se content of individual doping are 15 mol% and 10 mol% respectively, and 10 mol% Se is appropriate in 20 mol% Cd doping materials, while 15 mol% is the best doping content of Se in 25 mol% Cd doping materials.Structural and optical properties were characterized by XRD, UV-vis and fluorescence. The results showed that all products belong to the same kind of two-dimensional structure, and by changing the composition and doping level can systematically tune their optical properties. Band gap decreased after doping, and the largest decrease of 1.3 eV with 25 mol% Cd doping. Fluorescence intensity and luminous range increased at first, then decreased when increasing the doping level. The largest fluorescence intensity and luminous range occurred at 15 mol% Cd doping material, which is more larger than 2D-[Cd2S2（ha）].After annealing at 450℃for 30 minutes, the product structures were destroyed, band gap decreased, and the fluorescence intensity dropped drastically.