磷化铟量子点荧光峰的窄化设计和多色显示器件的应用研究

Quantum confined semiconductor nanocrystals, also known as quantum dots (QDs) are fascinating structures offering tremendous promise for light emitting devices and display technology, by virtue of their tunable emission, robust photo-stability and low fabrication cost. The application of conventional CdSe QDs in light emitting devices has been judged, because of environmental concerns on heavy metals. Indium phosphide QDs are featured as heavy-metal-free. Their emission was size-tunable in the visible region. A critical issue of InP quantum dots is the relatively wide emission, which is caused by the size and chemical heterogeneity. This drawback limits their application in light emitting devices, in particular in multi-color display. This proposal provide a pathway to address this issue by applying the combination of template method and successive atomic layer by layer deposition technique. We will apply uniform crystalline materials as template and deposit InP atomic layer on template by injection of cationic and anionic precursors alternatively. It is expected that the heterogeneity between ensembles during the steps of nucleation and growth will be eliminated. Hopefully, we will be able to fabricate InP quantum dots with narrow emission. The development of quantum dots lies at the intersection of chemistry, physics, materials science and engineering. The research direction proposed herein provide a novel and feasible pathway to advancing widely application of quantum dots light emitting device.

具有量子限域效应的半导体纳米晶被称作量子点。半导体纳米晶由于其发光可调、光学稳定、价格低廉等优点受到研究者的广泛关注，有望作为新型照明光源和显示技术中的核心材料。第一代硒化镉量子点由于重金属毒性问题制约了其在光电器件上的大规模应用。磷化铟量子点不含重金属，其荧光覆盖整个可见光区域，可以取代传统的硒化镉量子点。磷化铟量子点所面临的难题是如何通过提高结构的均一性，获得狭窄的荧光发射并能够满足全色显示的要求。本项目通过化学设计解决磷化铟发光峰宽化的问题。本项目的实验设计原理是基于化学模板法和胶体体系原子层外延生长法。利用具有尺寸结构均一的晶体材料作为模板，通过阴阳离子交替生长的方法实现可以精确控制磷化铟在模板上的生长。该方法避免了传统量子点合成方法在成核生长过程中的导致的颗粒间的不均一性，实现狭窄的荧光峰。研究计划的设计思路具有创新性，对于实现量子点的发光器件的大规模应用具有重要研究意义。

胶体半导体纳米晶表现出特殊的量子尺寸效应和量子限域效应，可以通过对化学组分、尺寸和结构的控制以实现对其发光峰位的调控。半导体纳米晶相比于真空物理方法制备的量子阱结构，具有价格低廉、容易实现柔性光电器件等优点，受到研究者的广泛关注。传统硒化镉量子点由于含重金属镉离子，其应用前景收到了限制。磷化铟量子点不含重金属，且其发光可以覆盖整个可见光区域，有望作为新型照明光源和显示技术中的核心材料，成为近几年来研究的重点。磷化锌量子点亟待解决的问题是如何提高结构的均一性。本研究探索了模板法，采用阴阳离子交替生长的方法实现了磷化铟在硒化锌模板上的可控生长。同时探索了渐变性合金壳层结构的制备工艺，以缓解磷化铟纳米晶和壳层之间的晶面张力，获得了高稳定的荧光量子点。研究中通过二苯基膦溶解硒粉，获取高活性的硒前驱体，并制备了高质量单分散性的硒化锌纳米晶。该方法可以提高对锌原子的转换效率，而且可以在相对较低温度下制备高质量的硒化锌纳米晶；在模板制备的基础上，通过调控前驱体的种类、反应温度实现了在模板上的可控生长。相关研究成果为磷化铟量子点的发光器件以及荧光检测等方向具有重要的研究意义。