Photoelectron spectroscopy investigations of pyrrolo[1,2-a][1,10]phenanthroline derivatives

Thin films of new pyrrolo[1,2-a][1,10]phenanthroline derivatives have been investigated by ultraviolet photoelectron spectroscopy, with a view of future applications in optoelectronic devices. The electronic band structure of investigated compounds (for electron energies ⩽25eV) is to a great extent determined by substituent (R = NO2, Cl) induced transformations of molecular orbitals.