Fluorescence Anisotropy Measurements, Simulations, and Noise Effects in Investigating Exciton Migration and...

This study explores the use of fluorescence anisotropy measurements to investigate exciton migration and confinement in MEH-PPV conjugated polymers immobilized in a PMMA host matrix. Computational simulations were used to analyze photoluminescence (PL) and emission polarization (P) data from samples following photo-induced partial degradation. The emergence of new PL emissions is attributed to exciton confinement at specific sites, with corresponding deviations from the expected P trends observed. We propose that exciton migration-blocking sites form during photo-induced degradation, restricting exciton migration, resulting in higher emission photon energy and P. Simulations further reveal that noise estimation error significantly impacts P data from higher PL energies, where emissions have low signal-to-noise ratios, which leads to measured P values lower than the true P values.