Dramatic photoluminescence quenching of phenylene vinylene oligomer thin films upon submonolayer Ca deposition

We report that Ca atoms severely quench the photoluminescence (PL) of an organic thin film 1,4-bis[4-(3,5-di-tert-butylstyryl) stryyl]benzene (4PV). A submonolayer coverage (0.035 monolayer or 0.1 Angstrom) of Ca on the 4PV surface reduced the PL of a 300 Angstrom layer of 4PV by as much as 50%. Three distinct quenching rates were observed throughout the 200 Angstrom Ca deposition. An exciton diffusion length of 200 Angstrom in 4PV is estimated assuming that the PL quenching is diffusion controlled. (C) 1996 American Institute of Physics.