PbS胶体量子点合成及其掺杂的研究
发布时间：2018-08-06 18:21
【摘要】：纳米尺度的PbS胶体量子点的能带从近红外区域蓝移到可见光区,这一特点使其呈现出与体相材料不同的光学性质和电学性质,因而被广泛应用于非线性光学器件、红外探测器以及太阳能电池等领域。这些器件一般可以通过掺杂来调整其载流子浓度。然而,实现PbS胶体量子点的稳定掺杂目前仍然是一个挑战。PbS胶体量子点在未经掺杂处理时通常表现为p型,如果PbS胶体量子点可以有n型特性,就可以与p型的PbS胶体量子点组合来制备同质结,从而避免高温烧结制备TiO2电极以及很多因为烧结所带来的问题。同时,同质结也可以避免异质结所产生的界面效应。另外钝化或掺杂还可以使量子点在呈现n型特性的同时拥有更好的电学性能。本文首先介绍了相关背景知识。包括量子点的基本概念及其物性,量子点掺杂的由来,目前发展的现状以及所存在的问题;然后阐明了量子点合成以及掺杂钝化的微观机理;接着介绍了一种以硫化氢(H2S)气体为硫源制备硫化铅(PbS)量子点的方法,分析温度和生长时间对粒径的影响;随后详细描述了阳离子置换法制备PbS胶体量子点以及后续四丁基碘化铵(TBAI)处理等掺杂过程。样品测试和数据分析工作包括:通过紫外-可见吸收峰判断粒子粒径的变化;通过傅里叶变换红外光谱判断处理前后有机键的变化情况;运用X射线衍射仪测试生成的PbS胶体量子点的结构。根据上述测试所得数据分析量子点性能与合成条件的关系,不断优化实验方案,并最终制备出掺杂良好、性能优异的单分散PbS胶体量子点。
[Abstract]:Nanoscale PbS colloidal quantum dots have been widely used in nonlinear optical devices due to their blue shift from near infrared region to visible region, which makes them exhibit different optical and electrical properties from bulk materials. Infrared detectors and solar cells and other areas. These devices can generally be doped to adjust their carrier concentration. However, it is still a challenge to achieve stable doping of PbS colloidal quantum dots. PBS colloidal quantum dots usually exhibit p-type when they are not doped. If PbS colloidal quantum dots can have n-type properties, It can be combined with p-type PbS colloidal quantum dots to prepare homogenous junctions, thus avoiding the preparation of TiO2 electrodes at high temperature and many problems caused by sintering. At the same time, the homogeneous junction can avoid the interface effect caused by the heterojunction. In addition, passivation or doping can make the quantum dots have better electrical properties as well as n-type properties. This paper first introduces the relevant background knowledge. It includes the basic concepts and physical properties of quantum dots, the origin of quantum dot doping, the current development and existing problems, and then expounds the micro mechanism of quantum dot synthesis and doping passivation. Then a method of preparing lead sulfide (PbS) quantum dots with hydrogen sulfide gas as sulfur source is introduced. The effects of temperature and growth time on particle size are analyzed. Then the doping process of PbS colloidal quantum dots prepared by cationic replacement method and subsequent four Ding Ji ammonium iodide (TBAI) treatment were described in detail. The work of sample testing and data analysis includes: the change of particle size is judged by UV-Vis absorption peak, the change of organic bond before and after treatment is judged by Fourier transform infrared spectroscopy (FTIR), and the change of organic bond is determined by Fourier transform infrared spectroscopy (FTIR). The structure of PbS colloidal quantum dots was measured by X ray diffractometer. According to the data obtained above, the relationship between the properties of quantum dots and the synthesis conditions was analyzed, and the experimental scheme was optimized. Finally, monodisperse PbS colloidal quantum dots with good doping and excellent performance were prepared.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O471.1
[Abstract]:Nanoscale PbS colloidal quantum dots have been widely used in nonlinear optical devices due to their blue shift from near infrared region to visible region, which makes them exhibit different optical and electrical properties from bulk materials. Infrared detectors and solar cells and other areas. These devices can generally be doped to adjust their carrier concentration. However, it is still a challenge to achieve stable doping of PbS colloidal quantum dots. PBS colloidal quantum dots usually exhibit p-type when they are not doped. If PbS colloidal quantum dots can have n-type properties, It can be combined with p-type PbS colloidal quantum dots to prepare homogenous junctions, thus avoiding the preparation of TiO2 electrodes at high temperature and many problems caused by sintering. At the same time, the homogeneous junction can avoid the interface effect caused by the heterojunction. In addition, passivation or doping can make the quantum dots have better electrical properties as well as n-type properties. This paper first introduces the relevant background knowledge. It includes the basic concepts and physical properties of quantum dots, the origin of quantum dot doping, the current development and existing problems, and then expounds the micro mechanism of quantum dot synthesis and doping passivation. Then a method of preparing lead sulfide (PbS) quantum dots with hydrogen sulfide gas as sulfur source is introduced. The effects of temperature and growth time on particle size are analyzed. Then the doping process of PbS colloidal quantum dots prepared by cationic replacement method and subsequent four Ding Ji ammonium iodide (TBAI) treatment were described in detail. The work of sample testing and data analysis includes: the change of particle size is judged by UV-Vis absorption peak, the change of organic bond before and after treatment is judged by Fourier transform infrared spectroscopy (FTIR), and the change of organic bond is determined by Fourier transform infrared spectroscopy (FTIR). The structure of PbS colloidal quantum dots was measured by X ray diffractometer. According to the data obtained above, the relationship between the properties of quantum dots and the synthesis conditions was analyzed, and the experimental scheme was optimized. Finally, monodisperse PbS colloidal quantum dots with good doping and excellent performance were prepared.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O471.1
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