Electrochemical and optical studies of conjugated polymers for three primary colours

Abstract

The Cyclic Voltammetry investigation and optical properties of some of the commonly used conjugated polymers for the fabrication of organic LEDs, like poly [2-methoxy 5- (2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly [2,3-bis (2-ethylhexyloxy)1,4-phenylenevinylene] (BEH-PPV) and poly[(9,9'-di(2'-ethylhexyl) fluoren-2,7-yleneethynylene]<b> </b>(PFE) for three principal emission colours red, green and blue, respectively have been reported. Both oxidation and reduction potentials of polymers were determined under the same experimental conditions to estimate the ionization potential (<i>I</i>_p: energy of Highest Occupied Molecular Orbital) and electron affinity (<i>E</i>_a: energy of Lowest Unoccupied Molecular Orbital). The optical band gaps of the polymers were obtained from their optical absorption spectra. A comparative study of the electrochemical and optical bandgap of the polymers has been made. The photoluminescence (PL) of the polymers has also been studied.