Electric field effect on luminescence, and photoconduction in electron donor–electron acceptor organic solid films

The electric field-induced exciplex photoluminescence quenching (up to 80%) is accompanied by remarkable photocurrents (up to 1 mA/cm2) in undoped and a PtL2Cl (L ≡ organic ligand) complex-doped blends of a starburst amine of m-MTDATA used as an electron donor and bathophenathroline (BPT) used as an electron acceptor. These results are rationalized by efficient dissociation of singlet 1∣m-MTDATA:BPT〉∗ and triplet 3∣m-MTDATA:PtL2Cl〉∗ exciplexes, and molecular excitons 1(m-MTDATA)∗ of the donor being exciplex precursors. While the dissociation determines the photoconduction of the blends, the interaction of molecular singlet excitons, 1(m-MTDATA)∗, with the photogenerated charge is the process that largely controls the quenching effects.