Photoinduced absorption in a poly(para-phenylene)-ladder type polymer

A methyl-substituted poly(para-phenylene)-type ladder polymer (m-LPPP) which is the conjugated polymer with the highest intramolecular order presently available is studied by absorption and photoinduced absorption (PIA) in the UV/VIS range. PIA measurements at different excitation waveىengths as well as the influence of temperature are reported. The observed features are attributed to the formation of singly charged polarons and neutral triplet excitons. For both quasi particles we find a vibronic structure which also appears in the absorption spectrum.