Bioinspired Supramolecular Packing Enables High Thermo-Sustainability.

Bottom-up self-assembled bio-inspired materials have attracted increasing interest in diverse fields. The use of peptide supramolecular semiconductors for optoelectronic applications is especially intriguing. However, the characteristic thermal unsustainability limits their practical application. Here, we report the thermal sustainability of cyclo-ditryptophan assemblies up to 680 K. Non-covalent interactions underlie the stability mechanism, generating a low exciton binding energy of only 0.29 eV and high thermal quenching activation energy of up to 0.11 eV. The contributing forces comprise predominantly of aromatic interactions, followed by hydrogen bonding between peptide molecules and, to a lesser extent, water-mediated associations. This thermal sustainability results in a temperature-dependent conductivity of the supramolecular semiconductors, showing 93% reduction of the resistance from 320 K to 440 K. Our results establish thermo-sustainable peptide self-assembly for heat-sensitive applications.