Processable amide substituted 2,5-bis(2-thienyl)pyrrole based conducting polymer and its fluorescent and electrochemical properties

Abstract

While majority of conductive polymers are insoluble and infusible, theirs solution processable derivatives are more desirable for preparing large size flat panel display and solid state applications because they are compatible with low cost, large area roll-to-roll manufacturing process. For this purpose, a solution-processable fluorescent conjugated polymer (PDOB), consisting of electron rich N-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-4-(dodecyloxy) benzamide (DOB) and its copolymer with 3,4-ethylenedioxythiophene P(DOB-co-EDOT) were synthesized by electrochemical polymerization technique. Electrochemical and optical properties of P(DOB) and P(DOB-co-EDOT) were investigated cyclic voltammetry, UV-vis absorption and fluorescence emission measurements, respectively. The optical bandgap values of P(DOB) and P(DOB-co-EDOT) determined by spectroelectrochemical data were 1.92 eV and 1.62 eV, respectively. P(DOB) and P(DOB-co-EDOT) were exhibited favorable redox activity and electrochromic performance. Further kinetic studies demonstrated that the P(DOB) and P(DOB-co-EDOT) have high optical contrast ratios (60-25%), favorable coloration efficiencies (139.1 cm2.C-1 and 80.6 cm2.C-1), fast response time (1.5 s; 1.0 s), high stability. When compared to soluble poly (2,5-dithienyl pyrrole) derivatives in literature, P(DOB) have lowest oxidation potential and bandgap and have highest optical contrast. As a result, these materials provide more plentiful electrochromic colors which useful for display application and hold promise for other solution-processable applications.