A in (III)-Based Organic-Inorganic Hybrid Compound: (C 4H 7N 2) 4[InBr 6][InBr 4]·2H 2O with a Two-Step Phase Transition and Switchable Dielectric Property
14 Pages Posted: 2 Jul 2020
Organic-inorganic hybrid phase transition compounds with dielectric switchable property have attract great intention, which can be used in data storage, sensing, NLO materials. Here, a new organic-inorganic hybrid phase transition compound (C 4 H 7 N 2 ) 4 [InBr 6 ][InBr 4 ]·2H 2 O( 1 ) is synthesized by In 2 O 3 and 4-methylimidazole in excess HBr. Two pairs of thermal anomaly peaks at 242/236 K (T 1 ) and 253/249 K (T 2 ) are presented in the DSC curves, the small heat hysteresis (6 K and 4 K) and the shape of the peaks indicating the second-order type of phase transition. Distinct dielectric anomaly are observed around the phase transition temperature, the value of dielectric constant in room temperature is four times higher than that in low temperature. Crystal structure analysis discloses that the order-disorder transition of 4-methylimidazole cations and change of the disorder degree in [InBr 4 ] - anions collectively induce the phase transition. This finding promotes the research on designing new In-based organic-inorganic hybrid compounds with dielectric property.
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