Investigations of optical properties of MEH-PPV/ZnO nanocomposites by photoluminescence spectroscopy

Abstract

The optical properties of hybrid composite films based on poly [2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) and zinc oxide (ZnO) nanoparticles of various sizes (5–20 nm) and with different concentrations have been investigated. The steady-state and time-resolved photoluminescence (PL) spectroscopy have been performed on nanocomposite films at room temperature. The PL results showed a significant enhancement in intensity in nanocomposites when using low nanoparticle concentrations (<5% ZnO). The particle size also impacts on the emission intensity by a larger emission efficiency in thin films containing small particles. In addition, a decrease in the photoluminescence lifetime of MEH-PPV composites has been also observed. Analysis of the time resolved PL decay of nanocomposite films suggests an energy transfer process from the nanoparticles to the polymer chains, in agreement with the steady state measurements.