Synthesis, structural characterization, Hirshfeld surface analysis, and electrical properties of a zinc (II)-based organic-inorganic hybrid compound

Recently, the family of hybrid organic-inorganic materials has attracted growing interest due to their versatile structures and favorable optoelectronic properties. In this paper, we presents a zero-dimensional (0D) compound, [Et3NH]2ZnCl4, where Et3NH represents the triethylammonium [(C2H5)3NH]+. The single crystals were synthesized using the slow evaporation solution growth method at room temperature. This newly synthesized compound crystallizes in the orthorhombic system. The asymmetric unit consists of a combination of two [ZnCl4]2- anions and four [Et3NH]+ cations. The thermogravimetric analysis shows no evidence of decomposition of the title compound up to 490 K. A comprehensive investigation was conducted on the electrical conductivity and relative permittivity over a frequency range of 50 Hz to 8 MHz across various temperatures. The Nyquist plots (-Z" vs Z') reveal contributions from both grains and grain boundaries, indicating the presence of non-Debye type relaxation. To model the electrical response, we employed an equivalent circuit consisting of a series combination of two (R//CPE) cells. By applying Jonscher's power law to the AC conductivity plots, the variation in the exponent 's' effectively describes the conduction mechanism, and aligns with the Correlated Barrier Hopping (CBH) model. The analysis of the DC conductivity data reveals that ion mobility adheres to Arrhenius behavior, with a thermal activation energy barrier of 1.16 eV. The compound demonstrates low dielectric loss and a high permittivity (epsilon similar to 104). These findings suggest that the [Et3NH]2ZnCl4 compound has significant potential for electronic and energy storage applications.