title: Reversible near-infrared light directed reflection in a self-organized helical superstructure loaded with upconversion nanoparticles.
abstract: Adding external, dynamic control to self-organized superstructures with desired functionalities is an important leap necessary in leveraging the fascinating molecular systems for applications. Here, the new light-driven chiral molecular switch and upconversion nanoparticles, doped in a liquid crystal media, were able to self-organize into an optically tunable helical superstructure. The resulting nanoparticle impregnated helical superstructure was found to exhibit unprecedented reversible near-infrared (NIR) light-guided tunable behavior only by modulating the excitation power density of a continuous-wave NIR laser (980 nm). Upon irradiation by the NIR laser at the high power density, the reflection wavelength of the photonic superstructure red-shifted, whereas its reverse process occurred upon irradiation by the same laser but with the lower power density. Furthermore, reversible dynamic NIR-light-driven red, green, and blue reflections in a single thin film, achieved only by varying the power density of the NIR light, were for the first time demonstrated.
authors.affiliation: Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University , Kent, Ohio 44242, United States.
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Dong
authors.forename: Yannian
authors.initials: Y
authors.lastname: Li
authors.forename: Chenming
authors.initials: C
authors.lastname: Xue
authors.forename: Ling-Dong
authors.initials: LD
authors.lastname: Sun
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Yan
authors.forename: Quan
authors.initials: Q
authors.lastname: Li