Abstract

The conjugated polymer poly-phenylenevinylene (PPV) and its derivatives have been the subject of numerous nonlinear optical¹ and light-emitting diode² studies. These polymers can photobleach in the presence of oxygen and the photo-oxidation can modify their optical properties.³ For instance, it was recently shown that the nonexponential photoluminescence decay of this polymer is caused by exciton quenching at defects.⁴ One type of defect has been identified as carbonyl groups formed on the polymer chain as a result of photo-oxidation.³ The present work explores the effect of C₆₀ doping on the photo-oxidative stability and the nonlinear optical (NLO) response of a derivative of PPV called poly-[2-methoxy,5-(2’-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV). Photoinduced electron transfer from the excited state of MEH-PPV to C₆₀ has been reported to occur on a subpicosecond time scale.³ By direct excitation into the tail of the π-π* transition of MEH-PPV, one may be able to access this charge transfer state, stabilize MEH-PPV against photo-oxidation, and enhance the NLO properties of the composite material.

© 1995 Optical Society of America