Long-Lived Defects In Polycarbazolyld1 Acetylenes. Photoinduced Vis And Infrared Spectra

Abstract

ABSTRACTPhotoinduced absorption spectra of different polycarbazolyldiacetylenes in the visible and infrared regions are reported. Long-lived bipolaronic defects, photogenerated by excitation above the band-gap (2.54 eV), are found responsible for the observed signals. Associated with these defects, photogenerated infrared active vibrations (IRAV) are observed as absorption bands or apparent bleachings arising from Fano-type interference. This different behaviour originates from the different degree of overlap of the IRAV Modes with the associated low-energy bipolaronic absorption.