Stabilization of photoejected electrons produced through two-photon ionization of dopant chromophores in electron-accepting polyester film

Anionic as well as cationic species formed through two-photon ionization of dopant chromophores in a copolymer (polyester) film having two weak electron-accepting groups, terephthaloyl and isophthaloyl groups, were simultaneously observed at 20 K by absorption measurement. It is found that most of the photoejected electrons migrate and are localized at higher electron-accepting terephthaloyl groups in the main chain of the polyester. The decay of both ionic species thus formed in the polyester film at low temperatures mainly results from charge recombination.