Piezoelectric Amino Acid Salts with Halogen‐Based Coformers Produce Exceptional Force‐Generated Voltage Output

ABSTRACT

Hierarchical self‐assemblies of bio‐inspired materials combine structural tunability with biocompatibility and environmental sustainability for multifunctional applications. Within this area of applied research, minimalistic building units such as amino acids and their derivatives have evolved as next‐generation piezoelectric materials. Their tendency towards chiral nature, polar molecular structure, asymmetric crystal packing, and designability enable efficient linear voltage generation under mechanical stress, yet their technological translation is at formative stages. Amino acid‐based multicomponent crystals ( MCC s) are an emerging class of sustainable piezoelectrics, which benefit from an integrated experimental‐theoretical approach for commercial advancement. In this work, the piezoelectric properties of nine non‐centrosymmetric amino acid salt crystals were confirmed experimentally using both piezoresponse force microscopy (PFM) and quasi ‐static piezoelectric measurements ( d ₃₃ = 7.8 pC/N) and calculated using density functional theory (DFT), with a maximum predicted longitudinal piezoelectric coefficient of 7.5 pC/N. A large open‐circuit voltage of 12.9 V was obtained for polycrystalline L‐histidinium trifluoroacetate under direct ambient mechanical stimuli, exceeding the open‐circuit voltage of ~6 V of a commercial ceramic disc. The close agreement between measured and computed electromechanical properties allows for correlations to be drawn between the MCC molecular structures and their macroscopic properties, facilitating the rational design of sustainable organic piezoelectrics.