Defect Quenching of Conjugated Polymer Luminescence

Transient photoluminescence measurements in poly($p$-phenylene vinylene) illustrate that exciton diffusion to quenching centers explains the nonexponential decay dynamics. The structure of these defects is studied by vibrational spectroscopy and the reason they act as quenchers is explained. In their absence, we observe nearly exponential photoluminescence decay with lifetime > 1 ns. The new picture of photoexcitations which emerges and its implications for polymer electroluminescent devices are discussed.