Understanding interactions between nanoparticles and small molecules is of significance for design of nanoparticle-based materials. Each citrate-coated silver nanoparticle (AgNP, 24 nm) in solution attracts 210,000 rhodamine 6G (R6G) molecules to assemble on its surface to form 170 nm "micelle-like" structures, where the fluorescence of the R6G molecules is efficiently quenched. The "micelles" can form agglomerates of 370 nm at higher concentrations. The R6G-AgNP self-assembly does not occur at higher R6G concentrations (>= 5 mu M) or can be prevented if AgNP is coated with polymers such as polyethylene glycol or polyvinyl pyrrolidone. (C) 2017 Elsevier B.V. All rights reserved.