Polymer light‐emitting electrochemical cell based on a novel poly(aryleneethynylene) consisting of ethynylfluorene and tetraphenyldiaminobiphenyl units

Abstract The photo‐ and electro‐luminescence properties of a novel light‐emitting poly(aryleneethynylene) (PAE) consisting of ethynylfluorene and hole‐transporting tetraphenyldiaminobiphenyl units have been reported. The emission color of this polymer changes from blue to yellowish green when going from the solution to the film, which is assigned to the formation of aggregates. The light‐emitting electrochemical cell (LEC) based on this PAE type polymer has been demonstrated. Light emission is observed from the LEC in both forward and reverse bias modes. The LEC shows the turn‐on voltage of 2.9 V and the maximum electroluminescence efficiency of 0.47 cd/A under the forward bias. Introduction of the hole‐transporting moiety into the main chain can improve the electroluminescence properties of the PAE type polymer. The a.c. impedance measurements indicate that the operation of the LEC corresponds to the electrochemical doping mechanism. Copyright © 2004 John Wiley & Sons, Ltd.