Metal organic frameworks (MOFs) are supramolecular architectures comprised of metal nodes connected by multi-dentate organic/inorganic linkers. Incorporation of molecular chromophores into these solid-state structures has been exploited to develop luminescent sensors, light emitting diodes, photovoltaics, and photo-catalysts. One interesting component to MOFs is the observation of super-quenching, i.e. complete loss in luminescence through the addition of an extremely low concentration of quencher. We approach this observation with one question – Why? In understanding the underlying mechanism of energy transfer in MOFs, we can develop structure-function relationships and enable the design of MOFs with optimized function. Herein, we will explore the effect of 3D structure on the efficiency of energy transfer in porphyrin-based MOFs. Through systematic variation of molecular chromophore spacing, we were able to explore the degree of electronic coupling and its effect on energy transfer efficiency. In addition, we explore energy transfer efficiency as a function of MOF crystallite size, providing the optimal distance over which energy can transfer in these MOF assemblies. Energy transfer efficiency is probed through photoluminescence, time-resolved photoluminescence, and transient absorption spectroscopy. We report these results with additional context provided by theoretical calculations of orbital interactions, work of our collaborator Elena Jakubikova (NC State).    <br/>

Structural insight into electronic communication and energy transfer in metal organic framework arrays

253rd National Meeting (2017)

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