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. J. Phys. Chem. Lett. 2013, 4, 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. J. Phys. Chem. C 2013, 117, 16783–16790.).