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 (c_AO). The absorption and fluorescence spectra of AO/PMA films exhibited a marked dependence on c_AO at low c_AO (c_AO < 2.1 × 10^− 1 mol kg^− 1), and were independent of c_AO at high c_AO (c_AO > 2.1 × 10^− 1 mol kg^− 1). The peak shift of fluorescence spectra with changing c_AO was as large as ∼ 100 nm.