title: Hierarchically structured ZnO/petal hybrid composites with tuned optoelectronic and mechanical properties.
abstract: Impressive biophotonic functions of flora in Mother Nature are often attributed to the optical diffraction occurring on hierarchically structured surfaces. The petals, displaying vivid colors, have diverse surface structures. The shapes of those structures alter significantly depending on the part of the petal, and they adjust the intensity of the reflected color and the light absorbance. Here, we added semiconducting properties to those intriguing optical functions arising from the unique surface structures. By means of atomic layer deposition (ALD), we conformally deposited a ZnO layer on the yellow rose petal, which has hierarchical surface structures and exhibits peculiar light absorbance behaviors. The resulting ZnO/petal composites revealed unique optoelectronic characteristics by synergetic effects between the biophotonic structures and inherent semiconducting properties. From several control experiments, we identified that the biophotonic hierarchical structures give rise to strong modulation of the light absorbance. We found that ZnO/petal exhibits superior mechanical stability to the raw petal likely due to the Zn infiltration into the petal. The design inspired by floral creatures with photonic structures and manufactured in the form of composite with mechanical stability and distinctive optoelectronic properties is believed to offer a new paradigm for the preparation of bioinspired photonic devices.
authors.affiliation: Nano Mechatronics, Korea University of Science and Technology (UST) , 217 Gajeong-ro, Yuseong-gu, Daejeon 305-333, South Korea.
authors.forename: Cheolmin
authors.initials: C
authors.lastname: Park
authors.forename: Hye-Mi
authors.initials: HM
authors.lastname: So
authors.forename: Hyeon Jun
authors.initials: HJ
authors.lastname: Jeong
authors.forename: Mun Seok
authors.initials: MS
authors.lastname: Jeong
authors.forename: Eckhard
authors.initials: E
authors.lastname: Pippel
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Chang
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Lee
mesh_terms: D035264:Flowers / Q000737:chemistry / Q000648:ultrastructure*; D055595:Mechanical Phenomena; D008954:Models, Biological; D053761:Nanocomposites / Q000737:chemistry / Q000648:ultrastructure*; D036103:Nanotechnology; D055095:Optics and Photonics; D027826:Rosa; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D015034:Zinc Oxide
keywords: atomic layer deposition; biophotonic hierarchical structure; biotemplate; flower; zinc oxide