Spatially resolved studies on addressable defects in hybrid organic-inorganic perovskite microcrystals prepared in the gas-phase

该项目的主要任务是创建由混合铅chalkogenide钙钛矿组成的新型微晶，作为空间分辨测量缺陷的发生将如何影响光电和电气性能的模型系统。项目第二阶段的挑战是创建一个可以打开（理想情况下再次关闭）缺陷的系统。这应该通过将特殊的反应性化合物掺入钙钛矿微晶中来实现。如果受到光的照射，或者暴露在电流或电场中，这些特殊的成分会改变它们的状态，从而在微晶中产生一种特殊类型的点缺陷。这种点缺陷的数量和密度将改变微晶的物理性质。一个非常有趣的情况是，如果点缺陷具有矢量性质，如偶极矩，因为这将在混合钙钛矿微晶中产生物理性质的各向异性。潜在地，缺陷还可彼此相互作用，从而导致集体缺陷特征。光电特性和电学特性将在单粒子基础上使用空间分辨技术进行研究，例如µ-光致发光，瞬态吸收显微镜和温度依赖性测量以及使用开尔文探针力显微镜测量的介电光谱。这将允许定义缺陷的影响并有意地引入缺陷以设计钙钛矿晶体的光电性质。

The main task of the project is to create novel microcrystals composed of hybrid lead chalkogenide perovskites as model systems for spatially resolved measurements on how the occurrence of defects will influence optoelectronic and electrical properties. The challenge for the second phase of the project is to create systems in which a defect can be turned on (and ideally off again). This should be achieved by the incorporation of special, reactive compounds into the perovskite microcrystals. These special constituents will change their state if radiated by light or if exposed to a current or to a field, thus giving rise to a special type of point-defect in the microcrystals. The number and density of such point-defects will alter the physical properties of the microcrystals. A highly interesting case is, if the point-defect has a vectorial property such as a dipole moment, because this will generate an anisotropy of physical properties in the hybrid perovskite microcrystals. Potentially, the defects may also interact with each other resulting in collective defect features. The optoelectronic properties and electrical properties will be investigated on a single-particle basis using spatially resolved techniques such as µ-photoluminescence, transient absorption microscopy and temperature-dependent measurements and dielectric spectroscopy using Kelvin-probe force microscopy measurements. This will allow to define the effect of defects and intentionally introduce defects to design the optoelectronic properties of perovskites crystals.