New Room-Temperature Molecular Ferroelectric (C6H16N2O)CdBr4·H2O with Preferable Luminescent Properties

Abstract

Organic–inorganic hybrid materials are easy to modify, which makes it possible to construct multifunctional ferroelectrics directionally and apply the built-in electric field and switching properties of ferroelectrics to multidisciplinary fields. Particularly, the coupling of photoluminescence and ferroelectricity in a single hybrid material facilitates its novel applications in lighting sensors, memory devices, and other multifunctional applications. Based on the photoluminescent molecule 4-(2-aminoethyl) morpholine (AEM), here, a room-temperature ferroelectric (C6H16N2O)CdBr4·H2O (AEM-CdBr4) is designed and obtained, which crystallizes in a polar orthorhombic space group of Pca21. A reversible ferroelectric–paraelectric phase transition was confirmed at 353 K through experimental results, such as differential scanning calorimetry (DSC) curves, variable-temperature Raman spectroscopy, and photoluminescence (PL) spectroscopy. The crystal exhibits ferroelectricity at room temperature with a saturation polarization of approximately 8 μC/cm2. The photoluminescence of compound AEM-CdBr4 is mainly derived from the monomeric fluorescence emission of the AEM molecule and is not directly related to the energy band structure of the crystal. This room-temperature molecular-type ferroelectric AEM-CdBr4 with photoluminescence will provide new ideas for the design of new multifunctional ferroelectrics.