双波长量子点可控制备及性质研究

Dual emissive quantum dots (QDs) have potential applications in many filed such as opto-elecronics, sensors and displya, because of their unique properties. Based on bandgap engineering theory, the project aims to scientifically design doped QDs containing two quantum system in one particle, and focus on investigating on the application by use dual QDs in the field of white light emitting diodes (LEDs). This single phase doped QD system consisting of doped cores/ barrier/doped well/ shell, which exhibits two doped emission peaks by controlling the barrier thicknessv(composition) under single-excitation wavelength, one of which being attributed to doped cores, and the other resulting from doped well, can be synthesized by flexible chemical methods. Through regulation of both the height and thickness of the interface barrier layer and electronic coupling degree between the doped cores and doped well, dual emission of doped QDs can be achieved. Furthermore, the dual emissive peaks were tunable in a range from visible to near-infrared by simple control of the size of the doped core size and the thickness of the doped well, respectively. The combination of a commercial blue LED chip with optimal dual emissive QDs as color converters would gave a high color rending index, Commission International de l’Eclairage color coordinates and suitable correlated color temperature. We hope that the single phase QD phosphor with dual emission has potential applications in white LEDs and correlated solid-state lighting, which would promote the QD’s application in real life

双波长量子点，即一个粒子发射两种波长的荧光，由于独特的性质在光电器件、传感器和显示等方面具有重要的应用前景。本项目旨在运用能带工程理论，通过构建核壳的方式构建双量子系统，科学地设计两个具有双波长荧光发射性质的量子点，并将其应用于制备白光量子点。通过柔性的化学方法，合成掺杂晶核/带垒层/掺杂量子阱复合结构量子点，通过调控界面带垒层的势垒高度和带垒层的厚度 (材料的组成），研究双量子系统内在性质变化规律，重点研究带垒层材料及其能级结构对复合结构量子点发光性质的影响。揭示带垒调控双波长纳米晶点发光变化规律，实现高效双波长量子点的可控制备。在此基础上，调控量子系统的组成与尺寸，实现高效双波长柔性可调的双光量子点可控制备，系统研究不同双光量子点与蓝光LED复合的白光LED的光学性质，最终实现高荧光效率、高显色指数白光量子点LED的可控制备。

具有双波长发射的半导体材料在光电功能材料领域展示出巨大的发展潜力，成为了科研工作者关注的热点材料。相比于广泛研究的以CdSe/CdS/ZnS构建多层核壳量子点等发光材料相比，全无机金属卤化物材料和低维有机无机金属卤化物材料逐渐在照明显示中展示出应用潜力。本项目包含两个方向的研究，分别是全无机铜基、银基金属卤化物的合成和低维有机无机金属卤化物材料的制备及光谱性质的研究。本项目构筑了多个系列具有丰富光学性质的金属卤化物材料，总结了这一系列材料的结构特点和光谱性质，并在白光LED器件、防伪等方面展示出潜在的应用。通过研究我们得到了如下结论：1) 采用机械球磨法制备了一系列铜基、银基金属卤化物材料。通过改变原料的组成，制备了不同构型的Cs-Ag-X (X=Cl, Br, I)材料，在紫外光激发时，发射光谱实现了蓝光到深红光的颜色可调。此外，通过将Cu+掺杂到Cs2AgI3中，研究了Cs2AgI3:Cu的X射线闪烁性能。2）利用四丙基氯化铵、氯化铅为前体，采用缓慢降温方法制备了1D针状的有机无机杂化金属卤化物晶体(TPA)PbCl3-Green，(TPA)PbCl3-Green化合物对热刺激展示出了可逆的荧光切换。通过改变环境温度，可以实现蓝/绿光的转换。指出其在防伪方面的潜在应用价值。3）成功构筑了以Sb3+、Sn2+掺杂的低维有机无机金属卤化物材料(CH3NH3)4[InCl6]Cl:Sb3+和[C5H14NO]CdCl3:Sn2+，指出了所制备材料高效的量子效率在照明领域的潜在应用。