Photophysical properties of supported dyes. Quantum yield calculations in scattering media

Aluminum tricarboximonoamidephthalocyanine and Rose Bengal were immobilized by adsorption and covalent linkage to different solid supports: silica, si lanized silica, silanized silica modified with polylysine chains and NovaSy n (R) TG amino resin (low cross-linked polystyrene with polyethyleneglycol chains). Specially designed tools were used to evaluate absolute quantum yi elds in scattering media. A previously developed model was used to calculat e fluorescence quantum yields in the solid state and a method is presented for the evaluation of singlet molecular oxygen quantum yields in suspension s. The method yields reliable results for dilute suspensions of particles w ith diameters much greater than the irradiation wavelength. Diffuse reflect ance and, in the case of suspensions, total transmittance spectra are the b asic inputs required. In this way the efficiencies of suspended solid photo sensitizers were obtained for all samples and correlated with the dye conce ntration and the way of linking to the surface.