CdSe基量子点发光二极管的制备和光电特性研究

发布时间：2018-01-25 10:20

本文关键词： QLED 电子传输层空穴传输层合金量子点　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：量子点在生物技术、太阳能电池和发光二极管等方面的应用引起了广泛关注。基于胶体量子点的发光二极管(quantum dot light-emitting diodes,QLED)具有启亮电压低、发光单色性好、低能耗、发光颜色可通过量子点尺寸调节和低成本的溶液法制备等优点,在显示领域和固态照明领域具有巨大的应用潜力。但仍需要提高QLED的亮度和器件的寿命才能达到商业化应用。目前,提高器件性能的主要途径包括设计新的器件结构、发展新的量子点和传输材料以优化载流子的注入。本文主要从载流子传输层和量子点层对QLED性能的影响两方面出发进行系统研究,主要内容如下:1.无机载流子传输层能避免有机载流子传输层在空气中的氧化和分解。采用溶液旋涂法成功制备出全无机载流子传输层的QLED。结合对载流子传输层的表征和对QLED光电特性测试,分析了全无机载流子传输层QLED发光效率低的原因。溶液法制备全无机载流子传输层QLED为低成本制备全无机QLED提供了方向。2.采用传统混合传输层的器件结构,分别研究了不同电子传输层和空穴传输层对QLED性能的影响。对于电子传输层,比较了ZnO和TiOx分别作为电子传输层对器件性能的影响。结果表明ZnO器件比Ti Ox器件电流密度更小,同时ZnO器件比TiOx器件具有更高的亮度和更低的启亮电压。对于空穴传输层,比较了聚四苯基联苯胺(Poly-TPD)与聚乙烯咔唑(PVK)分别作为空穴传输层对QLED性能的影响,并分别向其中掺入小分子有机物四苯基联苯胺(TPD)对载流子迁移率和能带进行调节。结果表明Poly-TPD器件比PVK器件性能更优,然而掺入小分子TPD后器件性能降低。结合载流子传输层自身的材料特性,对QLED光电特性测试结果进行分析。3.合金量子点与核壳量子点相比,有利于载流子的注入和激子的限制。我们采用一步法合成了CdSeZnS成分梯度合金量子点,并对量子点进行表征。表征结果显示合成的CdSeZnS合金量子点颗粒尺寸分布均匀,光致发光谱的发射峰为481nm。将合成的CdSeZnS合金量子点作为QLED的发光层制备出完整的器件,并测试了QLED的光电特性。
[Abstract]:Quantum dots in biotechnology. The applications of solar cells and light emitting diodes (LEDs) have attracted wide attention. Light emitting Diodes based on Colloidal Quantum Dots (. Quantum dot light-emitting diodes. QLED) has the advantages of low starting voltage, good monochromatic luminescence, low energy consumption, and can be prepared by quantum dot size adjustment and low cost solution method. There are great potential applications in the field of display and solid-state lighting. However, it is still necessary to improve the brightness of QLED and the lifetime of devices in order to achieve commercial applications. The main way to improve the performance of the device is to design a new device structure. New quantum dots and transport materials are developed to optimize carrier injection. In this paper, the effects of carrier transport layer and quantum dot layer on the performance of QLED are studied systematically. The main contents are as follows:. 1. Inorganic carrier transport layer can avoid oxidation and decomposition of organic carrier transport layer in air. QLED of all inorganic carrier transport layer has been successfully prepared by solution spin coating. Sign and test the photoelectric characteristics of QLED. The reason for the low luminescence efficiency of all-inorganic carrier transport layer (QLED) was analyzed. The preparation of all-inorganic carrier transport layer (QLED) by solution method provided the direction for low-cost preparation of all-inorganic QLED. 2. Traditional mixing was adopted. The device structure of the transport layer. The effects of different electron transport layer and hole transport layer on the performance of QLED are studied respectively. The effects of ZnO and TiOx as electron transport layer on the performance of the devices are compared. The results show that the current density of ZnO devices is smaller than that of TiOx devices. At the same time, ZnO devices have higher brightness and lower turn-on voltage than TiOx devices. The effects of poly (tetraphenylbenzidine) Poly-TPD) and polyvinylcarbazole (PVK) as hole transport layers on the properties of QLED were compared. The carrier mobility and band were adjusted by incorporation of small molecular organics, tetraphenylbenzidine (TPD). The results show that the performance of Poly-TPD devices is better than that of PVK devices. However, the performance of the device decreases after doping with small molecule TPD. Combining with the material characteristics of carrier transport layer, the photoelectric properties of QLED are analyzed. 3. The alloy quantum dots are compared with the core-shell quantum dots. In favor of carrier injection and exciton limitation, we have synthesized CdSeZnS gradient alloy quantum dots by one-step method. The results show that the particle size distribution of the synthesized CdSeZnS alloy quantum dots is uniform. The emission peak of photoluminescence spectrum is 481nm. The synthesized CdSeZnS alloy quantum dots are used as the luminescent layer of QLED. The photoelectric properties of QLED are tested.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8

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