Supramolecular gels and their modification for electrochemical application

Supramolecular gels with tailored optoelectronic behavior are of increasing interest for applications in soft electronics, sensing, and energy-related devices. In this study, we examined the donor–acceptor interactions of three aromatic amine donors, 2-aminoanthracene, 1-aminopyrene, and 2-aminonaphthalene, with diphenylalanine as the acceptor in both solution and gel phases. In solution, molar ratio studies revealed that the 2-aminoanthracene–diphenylalanine system displayed the strongest charge-transfer interaction, evident from a pronounced color change within 24 hours. The pyrene and naphthalene systems showed weaker responses under identical conditions. By increasing the gelator concentration, stable supramolecular gels were obtained, where similar charge-transfer trends were observed. Anthracene–diphenylalanine gels exhibited the fastest and most prominent optical and spectroscopic changes, followed by pyrene and then naphthalene. The mechanical strength of the gels was evaluated, and structural characterization by PXRD, FTIR, TEM, and fluorescence microscopy confirmed the presence of crystalline fibrous networks across all systems. Conductivity and photocurrent measurements further demonstrated that anthracene–diphenylalanine gels possessed superior electronic performance compared to the other donor–acceptor assemblies. To further enhance the functional properties, nanomaterials such as graphene oxide (GO), graphene quantum dots (GQDs), and carbon nanotubes (CNTs) were incorporated into the gels. Notably, CNT-doped gels exhibited the most significant improvements, showing enhanced conductivity and electron storage capacity. This enhancement is attributed to improved charge delocalization and the creation of efficient transport pathways within the fibrous matrix.

In summary, this work establishes diphenylalanine based donor–acceptor gels, particularly those incorporating 2-aminoanthracene, as versatile materials with promising optoelectronic features. The incorporation of CNT provides a simple yet effective strategy to boost conductivity and energy storage performance, opening new opportunities for developing soft, hybrid materials for advanced electronic and energy applications.