Photoinduced Absorption and Charge Transfer in Semiconducting Polymers
David Chapron, Jean-Michel Nunzi, Gabriela Aldea and Jack Cousseau
We present a study of photo-induced excited states and the effects on optical properties of charge transfer from donor-type semiconducting conjugated polymers to acceptor as C60-derivatives for two different systems insolution: poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) [MEH-PPV] and [6,6]-phenyl C 60 butyric acid methyl ester [PCBM] in 1,2-dichlorobenzene; and sulfonated polythiophene: sodium poly[2-(3-thienyl)ethoxy-4-butylsulfonate] [PTEBS] mixed with poly(maleic anhydride-alt-vinyl acetate) modified with C60-derivative in distilled water. In both, we observe charge transfer signature with photoluminescence quenching and the photo-induced absorption spectra reveal long lifetime carriers in the microsecond timescale. For MEH-PPV:PCBM, competition between charge transfer and bimolecular recombination is observed. Moreover, PTEBS:poly(MA-alt-VA)-C60 shows original behaviour of charge transfer efficiency due to hydrophobic/hydrophilic segregation.