Dresden 2020 – scientific programme

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DS: Fachverband Dünne Schichten

DS 46: Thin Film Properties: Structure, Morphology and Composition IV

DS 46.2: Talk

Friday, March 20, 2020, 11:30–11:45, CHE 89

Morphological and electrical characterization of mixed valence coordination polymers containing rhodium paddle wheels — •Daniel Steinbach, René Schmidt, and Florian Mertens — Institut für Physikalische Chemie, TU Bergakademie Freiberg

To overcome one of the disadvantages of most MOFs being isolators, conjugated coordination polymers are investigated regarding their electrical conductivity. Therefore paddle-wheel structures with a documented metal-metal bond, here rhodium derivates, were linked via conjugated organic molecules like pyrazine. Coordination polymers of this type were first synthesized as bulk materials, characterized using XRD, BET and XPS and then deposited as coatings on gold surfaces. Subsequently the topography of the deposited layers was measured. Different morphologies mainly determined by AFM were obtained by using spin coating and dip coating. Depending on the composition of the coordination polymer well distributed crystals or network like structures were found. The surface layers were further investigated by XPS and XRD. Direct current measurments were carried out on these systems by conductive AFM. The conductivity of our coordination polymers could be altered by oxidizing or reducing some metal atoms of the paddle-wheel structure, either via chemical or electrochemical oxidation, resulting in mixed valences. The dependency of the conductivity of the coordination polymer on the degree of oxidation was determined.