QLED载流子传输层的形貌调控和性能研究

发布时间：2018-03-12 17:11

本文选题：QLED　切入点：空穴传输层　出处：《东华大学》2014年硕士论文　论文类型：学位论文

【摘要】：QLED (Quantum Dots Light-Emitting Diode,量子点发光器件),是一种新兴的显示器件,结构与OLED(Organic Light-Emitting Diode,有机发光显示器)相似,即空穴传输层、发光层以及电子传输层组成的三明治结构。对比OLED, QLED的特点在于其发光材料采用性能更加稳定的无机量子点。量子点独特的量子尺寸效应、宏观量子隧道效应、量子尺寸效应和表面效应使其展现出出色的物理性质,尤其是其光学性能。相对于有机荧光染料,胶体法制备的量子点具有光谱可调,发光强度大、色纯度高、荧光寿命长,单光源可激发多色荧光等优势。此外,QLED的寿命长,封装工艺简单或无需封装,有望成为下一代的平板显示器,具有广阔发展前景。目前根据QLED中载流子传输层的不同,可将QLED分为四种。分别为聚合物载流子传输层QLED,有机小分子载流子传输层QLED,无机载流子传输层QLED,以及杂化载流子传输层QLEDo其中无机载流子传输层,空气稳定性最好,无需进行封装,是本文研究的重点。然而,目前无机载流子传输层QLED器件效率很低,主要原因在于空穴载流子和电子载流子传输速率不平衡造成量子点充电以及荧光淬灭。因此,本文主要采用水热法对空穴传输层形貌进行调控,从而提高空穴传输层中空穴载流子传输速率,以期提高QLED器件效率本文的研究内容主要如下： (1)采用水热法和磁控溅射法在FTO导电玻璃表面成功制备了NiO薄膜。其中通过改变水热生长时间,制备了微纳米叶片状、具有垂直网络结构的NiO薄膜。霍尔测试表明所制备的NiO均为p-型半导体。水热法制备的具有垂直结构的NiO薄膜其空穴传输速率明显高于磁控溅射的NiO薄膜。 (2)采用水热法和磁控溅射法在FTO导电玻璃表面成功制备了W03薄膜。其中通过改变水热溶剂和添加剂,制备了具有垂直生长结构的W03薄膜。霍尔测试表明所制备的W03薄膜均为p-型半导体。水热法制备的具有垂直结构的W03薄膜其空穴传输速率明显高于磁控溅射的W03薄膜。 (3)采用微流体技术成功制备了胶体量子点CdSe,并成功对其进行包覆,制备出了CdSe/ZnS量子点,包覆后荧光性能得到明显改善。通过改变合成工艺参数在很宽的范围内实现了发光光谱的调控。所合成的CdSe量子点荧光量子产率高达85%,核壳结构CdSe/ZnS量子点荧光量子产率高达90%。量子点粒径分布均匀,荧光半峰宽为17～30nm,并能维持优异的光纯度和光亮度。 (4)采用磁控溅射法制备了作为电子传输层的AZO薄膜,并完成了QLED整个器件的制备。对NiO-CdSe/ZnS-AZO和WO3-CdSe/ZnS-AZO两种QLED器件进行了I-E曲线测试。结果表明NiO-CdSe/ZnS-AZO具有良好的整流特性。
[Abstract]:QLED Quantum Dots Light-Emitting Diode, a new type of display device, is similar in structure to OLED(Organic Light-Emitting Diode, the hole transport layer. Compared with Ole, QLED is characterized by the use of more stable inorganic quantum dots, the unique quantum size effect of quantum dots, the macroscopic quantum tunneling effect, the unique quantum size effect, the macroscopic quantum tunneling effect, the unique quantum size effect and the macroscopic quantum tunneling effect. Quantum size effect and surface effect show excellent physical properties, especially their optical properties. Compared with organic fluorescent dyes, colloidal quantum dots have the advantages of adjustable spectrum, high luminescence intensity, high color purity and long fluorescence lifetime. The single light source can excite the advantages of polychromatic fluorescence. In addition, QLED has long life, simple packaging process or no packaging, which is expected to become the next generation of flat panel display, and has a broad development prospect. At present, according to the different carrier transport layer in QLED, QLED can be divided into four types: polymer carrier transport layer QLED, organic small molecule carrier transport layer QLED, inorganic carrier transport layer QLED, and hybrid carrier transport layer QLEDo, among which inorganic carrier transport layer has the best air stability. However, the efficiency of inorganic carrier transport layer QLED devices is very low. The main reason lies in the charge of quantum dots and fluorescence quenching due to the imbalance of carrier and electron carrier transport rate. Therefore, the morphology of the transport layer is mainly controlled by hydrothermal method. In order to improve the efficiency of QLED devices, the carrier rate of holes in the hole transport layer can be improved. The main contents of this paper are as follows:. (1) NiO thin films were successfully prepared on the surface of FTO conductive glass by hydrothermal method and magnetron sputtering method. Hall measurements show that the NiO films prepared by hydrothermal method are all p-type semiconductors. The hole propagation rate of NiO films with vertical structure prepared by hydrothermal method is obviously higher than that of NiO films deposited by magnetron sputtering. W03 thin films were successfully prepared on the surface of FTO conductive glass by hydrothermal method and magnetron sputtering. W03 thin films with vertical growth structure were prepared. Hall measurements showed that the prepared W03 thin films were all p-type semiconductors. The hole propagation rate of W03 films with vertical structure prepared by hydrothermal method was obviously higher than that of W03 films deposited by magnetron sputtering. The colloidal quantum dot CdSee was successfully prepared by microfluidic technique, and the CdSe/ZnS quantum dot was successfully coated. The photoluminescence spectrum of the CdSe quantum dots was regulated in a wide range by changing the synthesis parameters. The fluorescence quantum yield of the synthesized CdSe quantum dots was as high as 85 and the fluorescence quantity of the CdSe/ZnS quantum dots of the core-shell structure was up to 85. The yield of quantum dots is as high as 90. The particle size distribution of quantum dots is uniform. The half-width of the fluorescence peak is 17 ~ 30 nm, and it can maintain excellent light purity and luminance. (4) AZO thin films were prepared by magnetron sputtering, and the whole QLED devices were fabricated. The I-E curves of two kinds of QLED devices, NiO-CdSe/ZnS-AZO and WO3-CdSe/ZnS-AZO, were tested. The results show that NiO-CdSe/ZnS-AZO has good rectifying characteristics.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN873;TB383

【共引文献】