钙钛矿型层状固体模板制备硫化物半导体纳米材料

【作者】 许丽梅；

【导师】 陈晓；

【作者基本信息】 山东大学 ， 物理化学， 2006， 博士

【摘要】 半导体纳米粒子由于其介观尺寸的粒径(1-100nm)，而具有异于块体材料及单个分子、离子体系独特的物理和化学性能。将其组装成二维的纳米功能结构，是一种制造具有新型性能光电器件的潜在途径，在电子学、光学等领域展现出诱人的应用前景。本论文研究内容主要包括以下几部分： 第一部分是利用LB技术构筑卤化物钙钛矿层状固体模板，在分子水平上控制气固反应模板的微结构，并探讨模板对硫化物产物的调控作用。系统地考察了表面压的改变对LB膜中分子排列的影响：无机金属离子种类对LB膜模板无机层的影响；有机胺链中官能团的存在和小分子物质的引入对模板性质的影响以及模板对半导体硫化物材料形貌的控制。从而为精确解析硫化物纳米材料的形成机理提供有意义的理论参考。通过表面压．面积(π-A)等温线、紫外-可见吸收(UV-vis)光谱、傅立叶变换红外光谱(FTIR)、石英晶体微天平(QCM)、X-射线粉末衍射(XRD)和透射电子显微镜(TEM)等测试技术对反应前后模板的结构与性质变化、所得产物的形貌与性质进行考察，提出了可能的形成机理。 低表面压下，LB膜中分子未达到紧密双层排列，模板为无序结构，随着单层的压缩，表面压升高，单分子在空气／水界面所占的面积逐渐减少，分子排列趋于紧密，在较高的表面压下进行垂直提膜，可得到钙钛矿型层状固体模板。将不同表面压下构筑的铅模板与硫化氢气体反应，由于模板内部的微环境不同，最终得到无定形、棒形、立方体形以及圆盘形的硫化铅产物。在此过程中，烷基胺起到结构导向和表面钝化的作用。 但是上述表面压调控，对于锌(Ⅱ)LB膜模板则没有明显的效果，这主要是由于无机金属离子的不同，导致钙钛矿模板中无机层结构的差异造成的。在与硫化氢气体的反应过程中，气体主要是沿着无机层扩散的。钙钛矿模板中锌无机层为独立的四面体，而铅无机层则为八面体构型。不同的构型导致硫化氢气体扩散方式不同，锌硫化物主要是粘连的片状物。 将偶氮苯取代的有机胺与花生酸分子混合，考察了成膜分子在空气／水界面以及LB膜中可能的排列方式。模板的结构激子吸收与硫化铜产物的量子尺寸吸收峰相互作用，为新的光学器件的开发提供了一种参考途径。更多还原

【Abstract】 Due to their nano-size structures （1-100 nm）, semiconductor nanomaterials exhibit unique physical and chemical properties that differ from those of the bulk and the isolated ion or molecule system. The semiconductor nanoparticles can also be assembled into a two-dimensional structure, which could be a potential way to construct novel optoelectronic devices and shows fascinating applications in the electronic and optical field. There are three main experimental studies included in this dissertation.In the first part, layered metal halide perovskite solid templates are constructed by LB technique and their effect on metal sulfides’ morphologies are also investigated. We study systemically on the control of the surface pressure change, the species of the inorganic metal ions, the existence of functional groups in organic amine and the introduction of small molecule materials, which may influence the properties of the template. Surface-area isotherm curve, UV-visible absorption spectrum, quartz crystal microbalance, X-ray diffraction, and transmission electronic microscope methods are used to characterize the structure change of the template before and after reaction with H₂S gas and the products’ morphologies and properties. According to the obtained data, a possible control mechanism is proposed.Under lower surface pressure, molecules in LB films are not arranged closely, so the template is less ordered. With the increasing of the surface pressure, area per single molecule at air/water interface is reduced, and molecules arrange themselves closely with higher order. Perovskite solid template can be obtained at higher surface pressure via LB vertical lifting technique. Owing to different microenvironments in the template, reacting the PbCl-based perovskite template obtained at different surface pressure with H₂S gas, will result in amorphous, rod-like, cubic and disk-like nanomaterials. In this process, the amines act both as structure directing agents and surface passivation agents.Because of the difference of the inorganic layer structure, the above-mentioned更多还原