胶体量子点的高浓度合成及其应用研究

发布时间：2018-11-11 09:20

【摘要】：传统荧光粉制备的白光LED器件由于缺少红光区域,显色指数较低,使其应用受到很大限制。由于掺Mn量子点具有大的斯托克斯移动,几乎没有自吸收,且光谱可调等特性,其在白光LED等光电子器件领域上有着广泛的应用前景。本论文针对量子点高浓度合成及其在白光LED器件上应用等方面开展研究。本论文通过改进文献上的生长掺杂法,在1.5 L溶液中合成出了～10 g核壳结构掺Mn量子点,有利于量子点的工业化生产。通过改变Mn的掺杂过程和量子点的壳层结构,使得量子点的波长在564nm到616nm范围内可调。实验结果表明：配体浓度、单质S摩尔量及活性剂油胺的添加时间对量子点的高密度成核起重要作用。本论文以CdSe、CuInS_2和CdS:Mn半导体量子点为例,基于量子点的白光LED器件的电光转换过程,引入量子点的“类”光谱光效率函数,给出了这类器件的色坐标、光效和量子点配料质量等数值计算公式,理论计算了基于量子点的白光LED器件的性能参数值,并用实验进行了验证,且理论计算结果和实验结果是一致的。为了改善油性量子点的毒性和提高其荧光稳定性,扩大其使用范围,本论文通过改进的反相微乳液法在CdS:Mn/ZnS量子点表面包覆SiO_2壳层。从TEM图来看,量子点被很好地包覆在SiO_2壳层中。将量子点及其表面包覆SiO_2壳层的CdS:Mn/ZnS@SiO_2置于强紫外灯(波长为365nm,辐射强度为10 W/mm2)下照射,进行对比这两种样品的荧光强度和荧光寿命变化。实验结果表明,在量子点表面包覆SiO_2壳层后,可以有效地提高量子点的光化学稳定性。为了提高白光LED器件的稳定性、延长其使用寿命,本论文使用无机二氧化硅溶胶来代替传统硅胶封装材料。本论文将荧光峰位在610 nm的CdS:Mn/ZnS@SiO_2量子点掺入到YAG:Ce3+基白光LED器件中,实验显示了光谱中的红光区域得到了明显补偿,显色指数提高到88,显著的改善了YAG:Ce3+基白光LED器件的显色指数。
[Abstract]:Due to the lack of red region and low color index, the white LED devices fabricated by traditional phosphors are limited in application. Due to the large Stokes shift, almost no self-absorption, and spectral tunable properties of doped Mn quantum dots, they have wide application prospects in the field of white light LED and other optoelectronic devices. In this thesis, the high concentration synthesis of quantum dots and its application in white LED devices are studied. In this paper, Mn quantum dots with core-shell structure of ~ 10 g have been synthesized in 1.5L solution by improving the growth doping method in literature, which is beneficial to the industrial production of quantum dots. By changing the doping process of Mn and the shell structure of quantum dots, the wavelength of quantum dots can be adjusted from 564nm to 616nm. The experimental results show that the concentration of ligand, the molar amount of S and the addition time of oleamine play an important role in the nucleation of QDs. In this paper, taking CdSe,CuInS_2 and CdS:Mn semiconductor quantum dots as examples, based on the electro-optic conversion process of white light LED devices based on quantum dots, the "quasi-" spectral light efficiency function of quantum dots is introduced, and the chromatic coordinates of these devices are given. The theoretical calculation of the performance parameters of white light LED devices based on quantum dots is carried out and verified by experiments, and the theoretical results are in agreement with the experimental results. In order to improve the toxicity and fluorescence stability of oil quantum dots (QDs) and to expand their application range, the modified inverse microemulsion method was used to coat the SiO_2 shell on the surface of CdS:Mn/ZnS QDs. From the TEM diagram, the quantum dots are well encapsulated in the SiO_2 shell. The quantum dots and CdS:Mn/ZnS@SiO_2 coated with SiO_2 shell were irradiated with a strong ultraviolet lamp (wavelength 365 nm, radiation intensity 10 W/mm2). The fluorescence intensity and fluorescence lifetime of the two samples were compared. The experimental results show that the photochemical stability of quantum dots can be effectively improved by coating the SiO_2 shell on the surface of quantum dots. In order to improve the stability and prolong the service life of white LED devices, inorganic silica sol is used to replace the traditional silica packaging materials. In this paper, the fluorescence peak of CdS:Mn/ZnS@SiO_2 quantum dots at 610 nm is doped into the white LED device based on YAG:Ce3. The experimental results show that the red region of the spectrum is obviously compensated, and the chromogenic index is increased to 88. The color rendering index of white light LED devices based on YAG:Ce3 is improved significantly.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8

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