Electronic structure of poly(1,10-phenanthroline-3,8-diyl) and its K-dopedstate studied by photoelectron spectroscopy

Ultraviolet photoelectron spectra were measured using synchrotron radiation for thin films of poly(1,10-phenanthroline-3,8-diyl) (PPhen) and its potas sium-doped state. Upon potassium doping of PPhen, two new states, which cou ld be assigned to bipolaron bands, appear in the originally empty energy ga p. The electronic structure of the neutral and potassium-doped states was t heoretically analyzed using single-scattering approximation combined with s emiempirical molecular orbital calculations. (C) 1999 American Institute of Physics. [S0021-9606(99)70805-6].