ELECTROCHEMICAL COPOLYMERIZATION OF CROSS-LINKABLE POLYTHIOPHENE AND CARBAZOLE

Abstract

ABSTRACT The copolymerization of carbazole(C) and poly3-ethyl-3-({[6-(3-thienyl)hexyl]oxy}-methyl)oxetane(PTO) was successfully achieved electrochemically in CH 2 Cl 2 containing 25% boron trifluoride diethyl etherate BFEE(by volume) as supporting electrolyte by direct anodic oxidation of the monomer mixtures on platinum or an optically transparent ITO electrode. As-formed copolymer own the advantages of PTO, such as good electrochemical behaviors, excellent ambient stability. The structure of the copolymer were investigated by UV-vis, fluorescence spectra and thermal analysis, respectively. The fluorescence spectra indicate that PPTOC films are yellow-light emitters. Thermal analysis studies confirmed PPTOC has a good thermal stability. Keywords Polythiophene; Electrochemical polymerization; carbazole; Copolymerization; Boron trifluoride diethyl etherate 1. INTRODUCTION Inherently conducting polymers with π-conjugated electronic structures have been widely investigated since the late decades [1-3] due to their potential industrial applications based on their high conductivity and organic light-emitting. Conducting polymers are currently the subject of a board research area, especially for the applications in electronic and electrochemical devices such as organic field-effect transistors(OFETs),[4] organic light-emitting diodes(OLEDs),[5] polymer solar cells(PSCs),[6] and sensors.[7] Among these polymers, Poly(thiophenes) and poly(fluorene) have been received considerable attention. Such as poly(thiophenes) have been used in the development of electronic,[8] energy storage batteries,[9] photochromic devices,[10] and nonlinear optical devices.[11] The synthesis of conducting polymer films has been also an increasingly important subject of intensive research.[12-14]Polythiophenes(PTs) and their derivatives, as a class of conducting polymers, have attracted considerable attention due to their good conductivity and chemical stability in both the neutral and doped states.[15] To improve the optoelectronic properties and to realize the special applications, chemical modifications have been well performed,[16] one of which is the introduction of substituent with functional groups. So we synthesized a novel oxetane-functionalized cross-linkable conjugated polymer(PTO).[17]It is well known that copolymerization is one of efficient approaches to modify the properties of conducting polymers, which can produce copolymers with properties being intermediate between individual polymers. By means of the electrochemical copolymerization, some new conducting polymers have been prepared with several obvious advantages, such as variation of electrical conductivity, enhancement of electrochemical activity, and improvement of thermalstability. In this paper we report on the use of oxetane-functionalized cross-linkable conjugated polythiophene(PTO) and carbazole (C) were copolymerized successfully by direct electrochemical oxidation in CH