Abstract

Polymeric light-emitting diodes play an important role in scientific and industrial research due to possible applications in display technology. The diodes used for our experiments were built up in a layered structure consisting of a glass substrate, an indium tin oxide (ITO) transparent electrode, a poly(p-phenylene vinylene) (PPV) layer, and an aluminum-top electrode. The diode thus has various interfaces that can be well investigated by second-harmonic (SH) generation. For these investigations, we use an Nd:YAG laser (10 ns pulse duration, 10 mJ/pulse) and a monochromator/photomultiplier combination for the SH detection. With SH-scan measurements, we are able to detect the contributions of the various interfaces to the SH intensity. Because of its centrosymmetric structure, the PPV layer does not contribute to the SH signal, whereas the ITO-PPV and the PPV-aluminum interfaces do.

© 1998 Optical Society of America