Abstract: The fabrication of molecular structures with a desired morphology, e.g., nanotubes, nanoribbons, nanosprings, and sponges, is essential for the advancement of nanotechnology. Unfortunately, realization of this objective is expensive and complicated. Here, we report that irradiating a film comprising azobenzene derivatives with UV light produces oriented arrays of helical nanofilaments via the photoisomerization-induced Weigert effect. As a result, structural colors are observed due to the extrinsic chiral reflection in the visible wavelength range, and the reflected color can be tuned by adjusting the molecular length of the azobenzene derivative. This simple fabrication method can be used for fabricating large, reversible, and patternable color reflectors, providing a new platform for interference-based structural coloration as it exists in nature, such as morpho butterflies, green-winged teal, and various beetles.
Bibliographical noteFunding Information:
This study was supported by a grant from the National Research Foundation (NRF) and funded by the Korean Government (MSIT) (2017R1E1A1A01072798, 2017M3C1A3013923, 2017R1A5A1014862, and 2018R1A5A1025208). The experiments at PLS-II were supported in part by MSIT and Pohang University of Science and Technology. This work was also partially supported by IBS-R011-D1 and UMO-2016/22/A/ST5/00319.
All Science Journal Classification (ASJC) codes
- Modelling and Simulation
- Materials Science(all)
- Condensed Matter Physics