Ramifications of\nX‑Site Ion Modification in\na Zero-Dimensional Piezoelectric Tetrahalozincate

Using mixtures of A, B, or X site ions in piezoelectric\nhybrid\norganic inorganic materials has been shown to be an effective strategy\nto improve piezoelectric properties. Here, we investigated the effect\nof increasing Br content within histammonium tetrachlorozincate [HistNH3Zn(Cl<sub><i>x</i></sub>Br<sub>1–<i>x</i></sub>)4]\nby varying the relative amounts of Cl and Br from <i>x</i> = 0% to 100% on nonlinear optical and piezoelectric properties.\nWe found that the crystal structures were unchanged with Br percentages\nup to 100%, but the melting point of the materials changed substantially\nwith increasing Br content. On the other hand, the nonlinear optical\nproperties were only moderately affected with increasing Br content.\nThe piezoelectric response of each material was measured and compared\nwith DFT calculated values, both of which agreed that the overall\nthe materials had relatively similar <i>d</i><sub>33</sub> coefficients. The <i>x</i> = 75% Br compound had the largest\nmagnitude <i>d</i><sub>33</sub> value at maximum strain\nat both 29 °C (−97.56 pm/V) and 40 °C (−92.00\npm/V). The observed negative piezoelectric response is a rare trait\nthat was ascribed to the large number of intermolecular interactions\nbetween lattice elements, as described by others.