Towards solution-processible semiconducting polymer-based photonic devices

We demonstrate that the refractive indices of semiconducting polymer thin films can be tuned over significant ranges by dispersing nanosized dielectric particles into the polymer matrix. We have dispersed up to 30 vol% 50ه SiO2 or 55 vol% 10ه TiO2 particles into the conjugated polymer poly(p-phenylenevinylene) (PPV) and found no significant Mie scattering. A maximum decrease An=-0.75 at 550nm is measured for nanocomposites with 55 vol% TiO2. We have also fabricated semiconducting polymer photonic structures such as distributed Bragg reflectors and Fabry-Perot resonators by successive solution-deposition of alternate high- and low-index layers.