Optical Limiting from CdSe-Based Multiphase Polymer Nanocomposite Films

Abstract

Closely packed nanoparticles in polymer films are interesting materials where collective as interactive optical properties could be tuned based on nanoparticle proximity, surface morphology, types of encapsulation and matrix parameters. Two types of polymers (polymethylmethacrylate (PMMA) and polyvinyl alcohol (PVA))-based nanocomposite films featuring dual-colored emission peaks (~578 nm and ~650 nm) were fabricated from CdSe quantum dots to study their viability in optoelectronic applications. Using a 405 nm excitation laser, the evolution of photoluminescence (PL) intensities and peak wavelengths were examined as a function of increasing excitation intensity. While PL intensities showed systematic saturation and quenching, the emission wavelengths were found to be linearly red shifting with increasing excitation intensities in the PMMA films. The 650 nm emitting QDs seem to tune the PL saturation behavior in these films, as opposed to the PVA-based materials, where no such impact was seen. The material system could be a low-cost, low-maintenance alternative for future mesoscale sensing and light-emitting device applications.