Contact-Electrification-Regulated Amino Acid for Improving Materials' Triboelectric Properties.

The dual sustainability of energy and materials, especially through the use of green molecular building blocks, is of critical importance for next-generation self-powered systems. Here, we propose a contact-electrification (CE)-regulated molecular-engineering strategy to actively manipulate interfacial charge configurations in amino acid-based triboelectric films. Amino acid molecules intrinsically contain both electron-donating amino groups and electron-accepting carboxyl groups; however, a dominant exposure of amino groups is more favorable for positive triboelectric properties. By exploiting CE-driven interfacial electrostatic fields, preferential outward enrichment of amino groups and simultaneous interfacial anchoring of carboxyl groups and side chains to the underlying metal electrode are achieved, thereby maximizing interfacial charge transfer efficiency with a 1.51-fold enhancement. These findings demonstrate that molecular-level interfacial regulation, rather than material substitution alone, represents a fundamentally new paradigm for advancing triboelectric energy conversion. Notably, this CE-regulated molecular orientation mechanism originates from the amino and carboxyl groups shared by amino acids. This finding provides a molecular perspective for understanding and regulating interfacial charge transfer in a conserved donor-acceptor framework.