Tunable optical properties of conducting polymers infiltrated in synthetic opal as photonic crystal

Abstract

Various organic materials such as conducting polymers, insulating polymers, dyes , liquid crystals and carbons have been infiltrated in synthetic opals made by sedimentation of SiO 2 spheres. Optical properties of the opals exhibit drastic changes upon these infiltration. By removing silica with HF, replicas of opals was prepared with the infiltrated materials. Optical properties of synthetic opals infiltrated with conducting polymers are demonstrated to be tuned by various factors such as temperature and electrochemical doping in synthetic opals infiltrated with poly(3-alkylthiophene). These tunabilities were interpreted in terms of the change of refractive index by temperature and doping. Tuning of the optical properties by various factors were also demonstrated in the opal replicas. Polymer opals made of polymer spheres of several hundreds nanometer in diameter have also been prepared and the mechanical tuning has been demonstrated. Upon optical excitation of the synthetic opals infiltrated with conducting polymers and fluorescent dyes, spectral narrowing and lasing have been observed. The behaviors were confirmed to be dependent on the emission wavelength and the periodicity of the opals and the solvents used for infiltration. Two-dimensional periodic structures have been also fabricated upon irradiation of interfering optical beams on photo-polymers with azobenzene moieties in the side chains containing conducting polymers, in which directional PL emission have been demonstrated.