A composite particle that includes: a fluorescent semiconductor core/shell nanoparticle (preferably, nanocrystal); and a phthalic acid derivative attached to the core/shell nanoparticle outer surface, wherein the phthalic acid derivative (prior to attachment to the nanoparticle) has the following Formula (I): wherein each R is independently a linear or branched alkyl group having 6 or more carbon atoms and wherein n is 1 or 2.