PHOTOINDUCED ABSORPTION INVESTIGATIONS ON DONOR-ACCEPTOR POLYENES

Photoinduced absorption spectroscopy was performed on thin films of donor-acceptor polyenes with various end groups. The experiment shows a photoinduced bleaching (PB) of the pi - pi* transition and, depending on the end groups, one or two photoinduced absorption (PA) bands in the gap. For all samples the maximum of the PA bands increases almost linearly with increasing intensity of the pump laser. The photomodulation spectra are well resolved at low temperature, whereas they are quenched with increasing temperature.