Electrochromic effects on polymeric Co-pyridinoporphyrazine films prepared by electrochemical polymerization

Abstract A new storage type of electrochromic display utilizing a polymeric Co-3, 4-tetrapyridinoporphyrazine (poly-Co-QTPP) film is described. A violet-coloured film is obtained when the film electrode is subjected to a negative potential of −1.4 V versus a saturated caromel electrode (SCE) in a 1.0 M KCl aqueous solution. The colour of the film reverts to green at a positive potential of +1.8 rmV versus SCE. As a result of the polymeric structure, the poly-Co-QTPP film demonstrates excellent durability in repeated operation compared with a monomeric film. Furthermore, the reduced state of the film is stored for a long period of more than three months without electric power.