量子点白光LED的制备及其带宽特性研究

发布时间：2018-05-10 08:37

本文选题：量子点 + 白光发光二极管　；参考：《吉林大学》2017年硕士论文

【摘要】：本论文研究工作主要来源于国家杰出青年科学基金项目,半导体纳米材料制备和量子点光电器件,项目编号是61225018和国家自然科学基金面上项目,高效无机钙钛矿量子点发光二极管的制备及关键问题的研究,项目编号是61675086。可见光通信技术(visible light communication,VLC)是随着白光发光二极管(light-emitting diode,LED)照明技术的发展而兴起的无线光通信技术。白光LED具有功耗低、寿命长、尺寸小等优点,可以取代荧光灯、白炽灯等传统照明光源,成为下一代固体照明光源。与传统照明光源相比,白光LED又具有响应时间短、易于高速调制的特性,因此可以设计出基于白光LED的室内可见光无线通信系统和网络,实现照明和通信的双重功能。目前,可见光通信大多处于实验阶段,虽然整体系统已有实现,但还存在有待于解决的诸多问题。其中,如何制备高效率、高带宽的白光LED器件是可见光通信中的关键难题。本文针对此难题展开了详细的研究与讨论,采用短荧光寿命的胶体量子点(quantum dots,QDs)制备兼顾高发光效率和高带宽的照明通信两用白光LED,重点解决胶体量子点荧光粉与激发芯片组合器件所面临的关键性问题,以下是本文的主要研究内容:(1)研究了Cd Se/Zn S量子点,Ag In S2/Zn S量子点,Cs Pb X3(X=Cl,Br,I)钙钛矿量子点和聚合物点(ploymer dots,PDs)的性能,并分别采用这四种材料制备白光LED,分析了器件的光学特性及稳定性,其中重点研究了无毒短荧光寿命的聚合物点的性质。通过调节绿色和红色PDs的比例制备出一批高显色指数(color rendering index,CRI),色温可调的白光LED。(2)建立理论模型分析白光LED结构对其调制带宽的影响,并且拟合调制带宽与其蓝光Ga N芯片表面量子点荧光粉材料的荧光寿命和光通量之间的关系。分析蓝光Ga N芯片与量子点荧光粉之间的耦合发光对组合器件荧光寿命的影响机制和制约调制带宽的主要因素,实现荧光寿命优选的量子点荧光材料与激发源的有效匹配。(3)搭建白光LED器件调制带宽的测试电路,包括发射端电路和接收端电路。发射端电路加载调制信号,接收端采用高速光电二极管将光信号转换为电信号,经过运算放大器将信号放大,通过调节输入信号频率,最终测量得到LED的调制带宽。(4)分别选用不同荧光寿命的量子点材料:Cd Se/Zn S量子点、Zn Cu In S/Zn S量子点、聚合物点以及Cs Pb X3(X=Cl,Br,I)钙钛矿量子点和稀土YAG:Ce荧光粉材料制备白光LED器件,根据理论模型采用控制变量法逐一对模型中的变量进行实际调节,并进行实际器件带宽测试与表征,对比理论计算结果与实验结果,分析得出限制白光LED调制带宽的因素。本文的创新点是:首次将量子点作为荧光粉制备的荧光组合白光LED应用到可见光通信中,建立理论模型分析影响带宽的因素,兼顾照明要求的高显色性和高发光效率的同时,突破了传统荧光粉材料的带宽局限性。
[Abstract]:The research work of this thesis is mainly from the National Outstanding Youth Science Foundation project, semiconductor nanomaterials preparation and quantum dot optoelectronic devices. The project number is 61225018 and the National Natural Science Foundation of China. Preparation of highly efficient Inorganic perovskite Quantum Dot Light-emitting Diodes and study of key problems, item number is 61675086. Visible light Communication (VLC) is a wireless optical communication technology developed with the development of white light-emitting diode light-emitting diode (LED) lighting technology. White LED has the advantages of low power consumption, long life and small size. It can replace fluorescent lamp, incandescent lamp and other traditional lighting sources and become the next generation solid lighting source. Compared with the traditional lighting source, the white LED has the characteristics of short response time and high speed modulation. Therefore, the indoor visible light wireless communication system and network based on white light LED can be designed to realize the dual functions of lighting and communication. At present, most of the visible light communication is in the experimental stage. Although the whole system has been implemented, there are still many problems to be solved. How to fabricate white LED devices with high efficiency and high bandwidth is a key problem in visible light communication. In this paper, a detailed study and discussion of this problem is carried out. Using colloidal quantum dot quantum dots (QDs) with short fluorescence lifetime to prepare white LEDs with high luminescence efficiency and high bandwidth, the key problem of the combination of colloidal quantum dot phosphors and excitation chips is solved. The following is the main research content of this paper: (1) the properties of CD Se/Zn S quantum dots Ag in S2/Zn S quantum dots (Cs Pb X3H XCU ClCBI) perovskite quantum dots (PQDs) and polymer dots (POD) have been studied. The optical properties and stability of the devices were analyzed, and the properties of the nontoxic and short-lifetime polymer spots were studied. By adjusting the ratio of green and red PDs, a batch of high color index (rendering) CRI and white light (LED. 2) with adjustable color temperature were prepared. A theoretical model was established to analyze the influence of white light LED structure on its modulation bandwidth. The relationship between the modulation bandwidth and the fluorescence lifetime and luminous flux of the quantum dot phosphors on the surface of the blue gan chip is also fitted. The mechanism of the coupling luminescence between the blue gan chip and the quantum dot phosphor on the fluorescence lifetime of the composite device and the main factors restricting the modulation bandwidth are analyzed. The effective matching of fluorescence material and excitation source is realized. The measurement circuit of modulation bandwidth of white LED device is constructed, including transmitter circuit and receiver circuit. The transmitter circuit loads the modulated signal, the receiver uses high-speed photodiode to convert the light signal into an electric signal, the signal is amplified by an operational amplifier, and the input signal frequency is adjusted. Finally, the modulation bandwidth of LED was measured. (4) White LED devices were fabricated by using the quantum dots with different fluorescence lifetimes: Zn Cu in S/Zn S quantum dots, polymer dots, Cs Pb X3 + XCU ClCU Br-I) perovskite quantum dots and rare earth YAG:Ce phosphors. According to the theoretical model, the variables in the model are adjusted one by one by the control variable method, and the actual device bandwidth is measured and characterized. Compared with the theoretical calculation results and the experimental results, the factors that limit the bandwidth of white LED modulation are analyzed. The innovation of this paper is that the fluorescent combination white LED prepared by quantum dots as phosphor is applied to visible light communication for the first time, and the theoretical model is established to analyze the factors affecting the bandwidth and to take into account the high color rendering and high luminous efficiency of lighting requirements. It breaks through the bandwidth limitation of traditional phosphor material.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN312.8

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