Four new disubstituted propylenedioxythiophene polymers have been synthesized by Grignard metathesis on the 1−5 g scale. All polymers were found to be soluble in chloroform, methylene chloride, toluene, and tetrahydrofuran and were fully structurally characterized having GPC determined number-average molecular weights ranging from 33000 to 47000 g mol-1. Dilute polymer solutions in toluene exhibited strong red fluorescence with moderate quantum efficiencies from 0.38 to 0.50. Homogeneous thin films were formed by electropolymerization and spray casting polymer solutions onto ITO coated glass slides at thicknesses of ca. 150 nm. The films were electroactive, switching from a dark blue-purple to a transmissive sky blue upon p-doping, often with subsecond switching times, and high electrochromic contrast luminance changes (% ΔY) of 40−70%. These studies revealed that the branched derivatives, [poly(3,3-bis(2-ethylhexyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine)] and [poly(6,8-dibromo-3,3-bis(2-ethylhexyloxymethyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine)], gave an electrochemical response and associated color change over a much smaller voltage range in comparison to the linear chain substituted derivatives, [poly(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine)] and [poly(3,3-bis(octadecyloxymethyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine)]. Composite coloration efficiency values were found up to 1365 cm2/C; this was considerably larger than values obtained from previously studied alkylenedioxythiophene based polymers (∼375 cm2/C).

Electrochromic devices (ECDs) utilizing conjugated polymers as electroactive layers have received increased attention owing to their ease-of-color-tuning properties, fast switching times, and high contrast ratios. Our group has recently reported polymer-based ECDs, [1±4] including a transmissive/absorptive-type complimentary colored polymer ECD with an overall colorimetrically determined luminance change of 55 % in the visible region, which can be switched more than 20 000 times between its colored and transmissive states.[4] Throughout the world, a number of groups have utilized electrochromic (EC) polymers as at least one component of an ECD.[5±11]Traditionally, indium tin oxide (ITO) on either glass or plastic has been used as the electrode material in ECDs and electrochromic polymers were deposited electrochemically or cast from solution. While previous workers have claimed all-polymer ECDs, [6±8,12,13] their devices comprised ITO as the electrode material as no suitable highly conducting and transmissive organic polymer was available. Here, we report the construction and characterization of the first truly all-polymer ECD by replacing ITO with a conducting polymer, namely, poly(3,4-ethylenedioxythiopene)±poly(styrene sulfonate) (PEDOT±PSS). Since its discovery in the late 80 s, [14,15] PEDOT has proven to be an outstanding polymer for its electrochromic properties, high conductivity, and high stability in the doped form.[16] It has already found useful applications as antistatic film coatings, [17,18] electrochromic windows, [19] and as a hole-injection material in polymer OLEDs and PLEDs. [20] Further, water-soluble PEDOT derivatives have been used as polyelectrolytes in layer-by-layer assembled systems for electrochromic applications. [21,22] Here, we report on the use of PEDOT±PSS complex as the electrode material for polymer-based ECDs in order to form a device that is fully constructed from organic and polymeric components. We use a PEDOT±PSS aqueous dispersion (Agfa-Gevaert), as the resulting films are highly transmissive in the visible region, have high conductivity, and are unreactive (do not dedope) under the electrochemical conditions employed. Importantly, when used as the electrode material, PEDOT±PSS films do not return to the non-conducting form in the ECD's operating voltage range. In order to evaluate the suitability of PEDOT±PSS films as electrode materials, the films were first subjected to a reductive potential (±1. ) were obtained relative to those that we observe for switching the EC polymers (~3 mA cm ±2 ), indicating that the PEDOT±PSS electrodes are not redox active in this potential window. Once dried, they are well adhered to the plastic substrate and are insoluble in water and the electrolyte solutions used for electrochemical deposition and switching of EC polymers. Using PEDOT±PSS as the electrode material brings about the advantages of making flexible, stable, and truly all-organic ECDs.5The conductivity of the PEDOT±PSS films was determined both from spin-coated films of PEDO...

Donor-acceptor diblock copolymers, composed of regioregular poly(3-hexylthiophene) (rrP3HT) as the electron donor block and poly(perylene diimide acrylate) (PPDA) as the electron acceptor block, were prepared and used to fabricate a solar cell. Vinyl-terminated rrP3HT was synthesized by Grignard metathesis polymerization and converted to an alkoxyamine macroinitiator. This polythiophene macroinitiator was used in controlled free radical polymerization of a perylene diimide-containing acrylate. The targeted donor-acceptor diblock copolymers were prepared with low-to-moderate polydispersity indices (1.2-1.4) and molecular weights sufficiently high for producing films by spin-coating. These copolymers showed efficient photoluminescence quenching in the solid state, indicative of charge separation, and were used to produce a solar cell with power conversion efficiency of 0.49%.

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