Thursday, May 17, 2018

Abstract-Dielectric Properties of Zeolitic Imidazolate Frameworks in the Broad-Band Infrared Regime

Matthew R Ryder, (Jason) Zhixin Zeng, Kirill Titov, Jin-Chong Tan,

The field of metal-organic framework (MOF) materials is rapidly advancing towards practical applications, consequently it is urgent to achieve a better understanding and precise control of their physical properties. Yet research on the dielectric properties of MOFs is at its infancy, where studies are confined to the static dielectric behavior or lower frequency response (kHz-MHz) only. Herein we present the pioneering use of synchrotron-based infrared reflectivity experiments, combined with density functional theory (DFT) calculations to accurately determine the dynamic dielectric properties of zeolitic imidazolate frameworks (ZIFs: a topical family of MOFs). We show, for the first time, the frequency-dependent dielectric response of representative ZIF compounds, bridging the near-, mid-, and far-infrared (terahertz THz) broadband frequencies. We establish the structure-property relations as a function of framework porosity and structural change. Our comprehensive results will be paving the way for novel ZIF-based terahertz applications, such as infrared optical sensors and high-speed wireless communications.

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