Morphology and photophysical properties of polymer thin films dispersed with dye nanoparticle

We prepared nanoparticles of an organic dye, acridine orange (AO), dispersed in poly(methacrylic acid) (PMA) films by spin-coating the solution of the two components. The surface of the AO/PMA films became bumpier with increasing AO concentration (cAO). The absorption and fluorescence spectra of AO/PMA films exhibited a marked dependence on cAO at low cAO (cAO < 2.1 x 10-1 mol kg-1), and were independent of cAO at high cAO (cAO > 2.1 x 10-1 mol kg-1). The peak shift of fluorescence spectra with changing cAO was as large as ∼ 100 nm