title: Metal nanoparticle dispersion, alignment, and assembly in nematic liquid crystals for applications in switchable plasmonic color filters and E-polarizers.
abstract: Viewing angle characteristics of displays and performance of electro-optic devices are often compromised by the quality of dichroic thin-film polarizers, while dichroic optical filters usually lack tunability and cannot work beyond the visible part of optical spectrum. We demonstrate that molecular-colloidal organic-inorganic composites formed by liquid crystals and relatively dilute dispersions of orientationally ordered anisotropic gold nanoparticles, such as rods and platelets, can be used in engineering of switchable plasmonic polarizers and color filters. The use of metal nanoparticles instead of dichroic dyes allows for obtaining desired polarizing or scattering and absorption properties not only within the visible but also in the infrared parts of an optical spectrum. We explore spontaneous surface-anchoring-mediated alignment of surface-functionalized anisotropic gold nanoparticles and its control by low-voltage electric fields, elastic colloidal interactions and self-assembly, as well as the uses of these effects in defining tunable properties of the ensuing organic-inorganic nanostructured composites. Electrically tunable interaction of the composites may allow for engineering of practical electro-optic devices, such as a new breed of color filters and plasmonic polarizers.
authors.affiliation: †Department of Physics, University of Colorado, Boulder, Colorado 80309, United States.|‡Centre for Optical and Electromagnetic Research, Zhejiang University, Hangzhou 310058, People's Republic of China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: †Department of Physics, University of Colorado, Boulder, Colorado 80309, United States.
authors.forename: Qingkun
authors.initials: Q
authors.lastname: Liu
authors.affiliation: †Department of Physics, University of Colorado, Boulder, Colorado 80309, United States.
authors.forename: Haridas
authors.initials: H
authors.lastname: Mundoor
authors.affiliation: †Department of Physics, University of Colorado, Boulder, Colorado 80309, United States.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: †Department of Physics, University of Colorado, Boulder, Colorado 80309, United States.|§Department of Electrical, Computer, and Energy Engineering, Liquid Crystal Materials Research Center, and Materials Science Engineering Program, University of Colorado, Boulder, Colorado 80309, United States.|⊥Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, United States.
authors.forename: Ivan I
authors.initials: II
authors.lastname: Smalyukh
keywords: colloids; electro-optic switching; liquid crystals; metal nanoparticle; plasmonic polarizers and color filters; self-assembly; surface plasmon resonance