James P. Coleman

Printed, flexible electrochromic displays using interdigitated electrodes

Abstract We describe herein some of our initial studies in pursuit of a simple, economical method of mass producing electrochromic displays. The approach we have taken is to print the display on polymer film utilizing commercially available conductive inks in an interdigitated electrode structure with a conductive metal oxide powder, dispersed in a polymer binder, as the electrode surface. A range of electrochromic materials suitable for use with an aqueous gel electrolyte have been explored and examples presented.

Nanostructured metal oxides for printed electrochromic displays

Abstract Electrochromic devices are able to change their optical properties reversibly under the action of applied voltages. The conventional method of fabricating electrochromic devices utilizes a ‘sandwich’ configuration of electrodes. We developed a ‘side-by-side’ design for fabricating electrochromic display devices without the use of conductive, transparent electrodes. A simple printing technology can be used to produce commercial scale, flexible electrochromic displays. We have also discovered that tin oxide nanocrystallites heavily doped with antimony exhibit a high level of electrochromism. The high contrast ratio of nanostructured antimony–tin oxide (ATO) electrochromic displays is attributed to an accessible antimony energy state in the band gap of the mixed oxide. The fast switching rate can be attributed to the high surface area of, and high number density of grain boundaries in, the nanophase ATO materials. The interfacial regions between ATO nanocrystallites facilitate the transport of ions in and out of the electrochromic layer. The dynamics of the electrochromic displays is critically dependent on the nanostructure of the electrochromic layer. The design strategy for commercial production of printed, flexible electrochromic displays will be discussed.

Antimony-doped tin oxide powders:: Electrochromic materials for printed displays

Abstract We describe here the results of a preliminary investigation into the use of supported antimony-doped tin oxide (ATO) powders as electrochromic materials. When coated onto light-scattering, particulate substrates, ATO has been shown to exhibit a surprisingly high level of coloration. We will discuss some of the factors determining the magnitude of this effect and show examples of printed, interdigitated displays which are moving towards commercialization

Electrochromism of nanoparticulate-doped metal oxides: optical and material properties

Nanoparticulate antimony-doped tin oxide (ATO) has been used as the electrochromic material for the production of printed, interdigitated electrochromic displays. We report here some results on elemental and ionic modifications to the ATO in an attempt to improve electrochromic switching. We have also briefly studied the effects of antimony and tin distribution in the mixed oxide by a sequential preparation method. Lastly, we show here that the optical changes observed by electrically switching these displays are caused solely by changes in absorption coefficient of the ATO and not by any change in diffuse scattering coefficient related to refractive index modulation.

A practical system for manganese(III)-mediated electrochemical synthesis of sorbic acid precursors

An efficient, practical, electrochemical system was developed for the synthesis of a mixture of 4-acetoxy-5-hexenoic acid and trans-6-acetoxy-4-hexenoic acid via manganese (III)-mediated oxidation of acetic acid-acetic anhydride in the presence of butadiene. Copper (II) co-catalyst enhanced the efficiency of this oxidation and copper (I) was shown to catalyze in situ conversion of the acetoxyhexenoic acids into γ-vinyl-γ- butyrolactone.

Electrogenemtion of Mn(III) in an undivided cell

The electrochemical oxidation of manganous ion to manganic ion in acetic acid may be efficiently carried out in a parallel plate undivided cell. Reduction of manganic ion to manganous ion at the cathode is a relatively inefficient reaction, allowing the formation of solutions of manganic ion as high as 0.05 mol dm−3, at greater than 80% current efficiency. The effects of the major variables have been evaluated.

Homogeneous catalytic asymmetric hydrogenolysis of sodium epoxysuccinate: the first example of asymmetric hydrogenolysis of an epoxide

As the first example of asymmetric hydrogenolysis of an epoxide, the homogeneous catalytic asymmetric hydrogenolysis of sodium epoxysuccinate was accomplished by using rhodium catalysts containing chiral phosphine ligands.