Electron energy-loss investigation of the electronic structure of a ppp-related ladder polymer

Summary form only given. The electronic structure of a ladder polymer of PPP has been investigated by high-energy electron energy-loss spectroscopy (EELS) in transmission. The band gap in the undoped compound is seen to be shifted by about 0.4 eV towards lower energies in comparison with PPP. From the momentum dependent EELS data, the character of the /spl pi/ /spl rarr/ /spl pi/* transitions can be derived. Cls core-level absorption spectroscopy gives a direct measurement of the C2p derived unoccupied density of states. We also present studies of the optical absorption and luminescence emission of these new materials. Investigations on oriented and on doped samples will also be reported.