Electrosynthesis and Electrochromism of a New Crosslinked Polydithienylpyrrole with Diphenylpyrenylamine Subunits

Yu-Ruei Kung,Sin-Yun Cao,Sheng-Huei Hsiao

doi:10.3390/polym12122777

Yu-Ruei Kung, Sin-Yun Cao + Show 1 more

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https://doi.org/10.3390/polym12122777

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Abstract

A new electroactive monomer with two 2,5-di(2-thienyl)pyrrole (SNS) units and one diphenylpyrenylamine (DPPA) subunit, namely N,N-bis(4-(2,5-di(2-thienyl)-1H-pyrrol-1-yl)-phenyl)-1-aminopyrene (DPPA-2SNS), was synthesized from 1,4-di-(2-thienyl)butane-1,4-dione with N,N-di(4-aminophenyl)-1-aminopyrene through the Paal–Knorr condensation reaction. Visible and near-infrared (NIR) electrochromic polymer films could be facilely generated on the ITO-glass surface by the electrochemical polymerization of DPPA-2SNS in an electrolyte solution. The electro-synthesized polymer films exhibit multi-staged redox processes and multi-colored anodic electrochromic behavior. A multi-colored electrochromism, with yellowish orange, greyish blue, and purplish black colors, was observed in the polymer film by applying a positive potential. The polymer films exhibit reasonable coloration efficiency, fast response time, and good cycling stability, especially when switched between neutral and the first oxidation states. For comparison, N-(1-pyrenyl)-2,5-di(2-thienyl)pyrrole (Py-SNS) was also prepared and characterized with electrochemical and electro-optical properties.

Highlights

Electrochromism (EC) refers to a reversible change in the optical absorption or color of electroactive species as a result of electrochemical oxidation or reduction induced by a simple electric potential [1]
Owing to the attractive properties associated with the pyrene and triarylamine moieties, we have developed many diphenylpyrenylamine (DPPA)-based polymers with dual fluorescent and electrochromic functions [24,25,26]
Due to the highly fluorescent property of pyrene moiety and redox-activity of triarylamine unit, incorporation of diphenylpyrenylamine (DPPA) subunit into the SNS monomer may lead to new compounds and PSNS with dual fluorescent and electrochromic functions

Summary

Introduction

Electrochromism (EC) refers to a reversible change in the optical absorption or color of electroactive species as a result of electrochemical oxidation or reduction induced by a simple electric potential [1]. There are many types of EC materials that have been developed, including inorganic metal oxides, organic small molecules, organic π-conjugated polymers, and organic–inorganic coordination polymers [8]. Organic π-conjugated polymers demonstrate a number of advantages over inorganic and organic small molecule materials [9,10,11,12]. They possess great potential for the fabrication of flexible devices, diverse and multicolored electrochromisms, facile molecular design, and high coloration efficiency. Triphenylamine (TPA) and its derivatives are the important building blocks for the preparation of electroactive molecules because of their excellent electron donating nature, the easy oxidizability of their nitrogen center, and their ability to transport charge carriers with high stability [13,14,15]

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