Piezoelectric Hydrogen Bonding: Computational Screening for a Design Rationale

Organic piezoelectric materials are promising targets in applications such as energy harvesting or mechanical sensors and actuators. In a recent paper (Werling, K. A.; et al. <i>J. Phys. Chem. Lett.</i> <b>2013</b>, <i>4</i>, 1365–1370), we have shown that hydrogen bonding gives rise to a significant piezoelectric response. In this article, we aim to find organic hydrogen bonded systems with increased piezo-response by investigating different hydrogen bonding motifs and by tailoring the hydrogen bond strength via functionalization. The largest piezo-coefficient of 23 pm/V is found for the nitrobenzene–aniline dimer. We develop a simple, yet surprisingly accurate rationale to predict piezo-coefficients based on the zero-field compliance matrix and dipole derivatives. This rationale increases the speed of first-principles piezo-coefficient calculations by an order of magnitude. At the same time, it suggests how to understand and further increase the piezo-response. Our rationale also explains the remarkably large piezo-response of 150 pm/V and more for another class of systems, the “molecular springs” (Marvin, C.; et al. <i>J. Phys. Chem. C</i> <b>2013</b>, <i>117</i>, 16783–16790.)