Synthesis and characterization of soluble polythiophene derivatives containing electron-transporting moiety

Soluble pi -conjugated polythiophene derivatives containing the electron-tr ansporting moiety were synthesized through FeCl3-oxidative polymerization; poly( 3-(2-benzotriazoloethyl)thiophene)(PBET) and poly(3-(2-(5-chlorobenzo triazolo)ethyl)thiophene) (PCBET). The structure of the polymers was verifi ed by FT-IR, H-1 NMR, and element analysis. Introduction of the electron-tr ansporting moiety, benzotriazole, on the side chain in poly(3-alkylthiophen e) was an attempt to balance the injection rates of the electron and the ho le from the opposite electrode into the light-emitting diodes (LEDs). This modification, therefore, would enhance electroluminescence (EL) efficiency. As the result, the external EL quantum efficiencies of PBET and PCBET were 7 and 3 times higher than that of poly(3-octylthiophene) (POT).