Jia Chu

Modulating the Electrochromic Performances of Transmissive and Reflective Devices Using N,N-Dimethyl Formamide Modified Poly(3,4-Ethylenedioxythiophene)/Poly(Styrene Sulfonate) Blend as Active Layers

As one of the important factors which affect the properties and applications of conducting polymers, the electrical conductivity of a poly(3,4-ethylenedoxy-thiophene)/ poly(styrene sulfonate) (PEDOT: PSS) blend was adjusted by using various amount of an organic solvent (N,N-dimethyl formamide, DMF) as an additive. The conductivities of PEDOT: PSS thin films can be increased dramatically, from 1.0 S to 32.1 S cm−1, with a 2/1 volume ratio of PEDOT: PSS/DMF loading after totally removing the organic solvent by annealing the film at 80° for 48 h in a vacuum oven. The optical contrasts of transmissive and reflective devices assembled using DMF-modified PEDOT: PSS as active layers exhibited a close relationship with the conductivity of PEDOT: PSS. Interestingly, high conductivity of PEDOT: PSS enhanced the contrast of a transmissive device, while high conductivity of PEDOT: PSS decreased the contrasts of a reflective device. The underlying reason is related to the different electrochromic mechanisms of these two types of device configurations.

Electrochromic Behaviors of Water-Soluble Polyaniline with Covalently Bonded Acetyl Ferrocene

A novel ferrocene-containing hybrid electrochromic material was synthesized via copolymerization of aniline with p-phenylenediamine functionalized acetyl ferrocene in the presence of poly (styrene sulfonate) dopant in an aqueous medium, and neat polyaniline (PANI) was prepared for comparison. The polymerization characteristics and the structure of the copolymer were systematically studied by Fourier-transform infrared, meanwhile, their electrochromic properties and electrochemical behaviors were tested by UV–vis spectra, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). It was found that the strong covalent bond and large conjugated system between PANI and ferrocene enhance the electron transfer rate and electron delocalization in the ferrocene-polyaniline (Fc-PANI) hybrid. In particular, the electrochromic device with Fc-PANI as the active layer shows significant enhancement in optical contrast over the PANI-based device.