Cathodic Electrochromism of Lutetium Diphthalocyanine Films

Abstract

Cathodic electrochromism of lutetium diphthalocyanine films on insulating substrates was investigated by a moving‐boundary technique. Reduction occurred by injection of electrons from a gold contact and cations from a liquid electrolyte. Light blue products formed with aqueous or organic solutions of alkali metal salts, while a dark violet product formed with aqueous hydrochloric acid. The dark material had a charge‐carrier mobility of 8×10−7 cm2/normalVsec and an estimated bulk resistivity of 1800 Ω‐cm. Reduced forms of the dye appear to be solid cation conductors.

Lanthanide diphthalocyanines. Electrochemistry and display applications

“…Stabilities of red forms propagated in lutetium diphthalocyanine films with different anions were compared by observing changes in the absorption spectrum on open circuit for about 20 hr while the lower end of the film remained in the electrolyte (Pizzarello and Nicholson, 1981).…”

“…In this more usual cell configuration, the reaction occurred in milliseconds to seconds, (Moskalev and Kirin, 1970a;1970b;Moskalev and Alimova, 1975) that the green-to-blue transformation of a lutetium diphthalocyanine film is due to fieldinduced acid ionization of the dye ts contradtcted by later ftndtngs that one or more electrons are gained in the process Galiardi, 1977, 1978;Nicholson and Pizzarello, 1981). Ntcholson and…”

“…With the dye on tin oxide, completely immersed in aqueous KC1, both light and dark blue, as well as violet, cathodic products can be formed Galiardi, 1977, 1978). Protonation of the dye in the neutral electrolyte may occur indirectly by coupled chemical reaction with cathodic hydrogen adsorbed on tin oxide, rather than by direct electron and proton injection into the organic solid (Nicholson and Pizzarello, 1981).…”

“…They are also more soluble than the green form in organic solvents such as acetonitrile and dimethyl sulfoxide (Nicholson and Pizzarello, 1981). For these reasons, the reduced forms are more difficult to handle experimentally than the oxidation products.…”

Preparação e caracterização de compósitos SiO2/Nafion® e TiO2/Nafion®

“…[26] A Figura 1d ilustra esquematicamente um display eletrocrômico que é, essencialmente, uma "bomba" (pump) de hidrogênio reversível proporcionando a hidrogenização e a desidrogenização de uma camada eletrocrômica que responde com a coloração e a descoloração, respectivamente. Para o material do cátodo, compostos metalorgânicos, tais como, ftalocianinas de terras raras [27][28][29] ou compostos inorgânicos de intercalação de hidrogênio tais como WO 3 e MoO 3 são largamente utilizados. Estes últimos são frequentemente usados especialmente em janelas, juntamente com outro material eletrocrômico, como contraeletrodo, que apresenta coloração anódica tais como o Azul da Prússia [30] , o óxido de irídio [31] ou polianilina [32] .…”