Peptide Sequence Programmed Piezoelectric Response by Supramolecular Self-Assembly

Piezoelectricity has attracted significant attention for its ability to convert mechanical energy into electricity, especially when biological molecules are incorporated into materials. However, natural biomaterials are limited by low piezoelectric coefficients, necessitating synthetic alternatives. Short peptides offer advantages such as ease of synthesis, biocompatibility, and tunability, making them promising candidates. In this study, hydrophobic tripeptides are used to fabricate stable piezoelectric crystals. When phenylalanine occupies the central position, the tripeptides self-assembled into uniform, thermally stable crystals. Piezoresponse force microscopy (PFM) reveals a high effective piezoelectric coefficient of 24.0 pC N^-1, attributed to strong asymmetric molecular packing, confirmed by microcrystal electron diffraction (MicroED) and density functional theory (DFT) analysis. Nanogenerators based on these crystals achieve an open-circuit voltage of 2.57 V under 50 N, the highest among short peptides in aqueous environments. These findings advance peptide crystal engineering and highlight their potential for high-performance piezoelectric devices.