Graphene oxide-assisted self-assembly of diphenylalanine nanostructures for enhanced piezoelectric nanogenerators

Abstract

This study reports the large-scale fabrication of unidirectionally aligned diphenylalanine/graphene oxide (FF/GO) nanocomposites via a meniscus-driven self-assembly method in a biocompatible solvent system. The fabricated FF/GO nanocomposites were experimentally confirmed to retain the intrinsic biocompatibility of their constituent materials. The non-covalent interactions between FF and GO, primarily hydrogen bonding with a possible contribution of pi-pi interactions, promote heterogeneous nucleation on the GO surface, leading to enhanced crystallinity and increased crystallite size. At an optimal GO concentration (0.25 mg mL(-)& sup1;), the nanocomposites maintain a highly unidirectional polarization state comparable to pristine FF, while moderately improving the intrinsic shear-mode piezoelectric constant (d(15)) due to superior molecular packing. The fabricated piezoelectric nanogenerator (PENG) based on the optimized FF/GO composite delivered a peak open-circuit voltage of 1.33 V, a short-circuit current of 0.32 mu A, and a power density of 97.57 mu W cm(-)& sup2;, which represents a similar to 22-fold enhancement compared to pristine FF devices. Furthermore, the device demonstrated high sensitivity to applied pressure (1.25-6.25 MPa) and excellent mechanical durability over 12,000 cycles. These findings suggest that the integration of GO can serve as a beneficial scaffold to maximize the electromechanical performance of bio-derived materials, providing a robust platform for self-powered, implantable bioelectronic systems.