title: Dielectric, electro-optical, and photoluminescence characteristics of ferroelectric liquid crystals on a graphene-coated indium tin oxide substrate.
abstract: Multilayer graphene was deposited on indium tin oxide (ITO) -coated glass plates and characterized by suitable techniques. A liquid crystal sample cell was designed using graphene deposited ITO glass plates without any additional treatment for alignment. Ferroelectric liquid crystal (FLC) material was filled in the sample cell. The effect of multilayer graphene on the characteristics of FLC material was investigated. The extremely high relative permittivity of pristine graphene and charge transfer between graphene and FLC material were consequences of the enormous increase in relative permittivity for the graphene-FLC (GFLC) system as compared to pure FLC. The presence of multilayer graphene suppresses the ionic impurities, comprised in the FLC material at lower frequencies. The ionic charge annihilation mechanism might be responsible for the reduction of ionic impurities. The presence of graphene reduces the net ferroelectricity and results in a change in the spontaneous polarization of pure FLC. Rotational viscosity of the GFLC system also decreases due to the strong π-π interaction between the FLC molecule and multilayer graphene. The photoluminescence of the GFLC system is blueshifted as compared to pure FLC, which is due to the coupling of energy released in the process of charge annihilation and photon emission.
authors.affiliation: Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow 226007, India.
authors.forename: Dharmendra Pratap
authors.initials: DP
authors.lastname: Singh
authors.affiliation: Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow 226007, India.
authors.forename: Swadesh Kumar
authors.initials: SK
authors.lastname: Gupta
authors.affiliation: Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow 226007, India.
authors.forename: Tripti
authors.initials: T
authors.lastname: Vimal
authors.affiliation: Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow 226007, India.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Manohar
mesh_terms: D004553:Electric Conductivity; D005898:Glass / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D049449:Luminescence; D008855:Microscopy, Electron, Scanning; D061848:Optical Imaging; D017785:Photons; D012399:Rotation; D013059:Spectrum Analysis, Raman; D013696:Temperature; D017971:Tin Compounds / Q000737:chemistry*; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D017971:Tin Compounds; C109984:indium tin oxide; D006108:Graphite