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

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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.