Long-range ordered amino acid assemblies exhibit effective optical-to-electrical transduction and stable photoluminescence

Bio-endogenous peptide molecules are ideal components for fabrication of biocompatible and environmentally friendly semiconductors materials. However, to date, their applications have been limited due to the difficulty in obtaining stable, high-performance devices. Herein, simple amino acid derivatives fluorenylmethoxycarbonylleucine (Fmoc-L) and fluorenylmethoxycarbonyl-tryptophan (Fmoc-W) are utilized to form long-range ordered supramolecular nanostructures by tight aromatic stacking and extensive hydrogen bonding with mechanical, electrical and optical properties. For the first time, without addition of any photosensitizers, pure Fmoc-L microbelts and Fmoc-W microwires exhibit Young's modulus up to 28.79 and 26.96 GPa, and unprecedently high values of photocurrent responses up to 2.2 and 2.3 mu A/cm(2), respectively. Meanwhile, Fmoc-W microwires with stable blue fluorescent emission under continuous excitation are successfully used as LED phosphors. Mechanism analysis shows that these two amino acids derivatives firstly formed dimers to reduce the bandgap, then further assemble into bioinspired semi-conductor materials using the dimers as the building blocks. In this process, aromatic residues of amino acids are more conducive to the formation of semiconducting characteristics than fluorenyl groups. Statement of significance Long-range ordered amino acid derivative assemblies with mechanical, electrical and optical properties were fabricated by a green and facile biomimetic strategy. These amino acid assemblies have Young's modulus comparable to that of concrete and exhibit typical semiconducting characteristics. Even with-out the addition of any photosensitizer, pure amino acid assemblies can still produce a strong photocurrent response and an unusually stable photoluminescence. The results suggest that amino acid structures with hydrophilic C-terminal and aromatic residues are more conducive to the formation of semiconducting characteristics. This work unlocks the potential for amino acid molecules to self-assemble into high-performance bioinspired semiconductors, providing a reference for customized development of biocompatible and environmentally friendly semiconductor materials through rational molecular design.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Amino acid derivatives are used to form long-range ordered supramolecular nanostructures with mechanical, electrical, and optical properties, exhibiting semiconductor characteristics. This study uncovers the potential for amino acid molecules to self-assemble into high-performance bioinspired semiconductors, providing a reference for the customized development of biocompatible and environmentally friendly semiconductor materials through rational molecular design.