Polyamine-quantum dot nanocomposites: Linear versus starburst stabilizer architectures

Recently, a number of research groups have found that dendrimers are effective templates for the synthesis of inorganic nanomaterials (Sooklal, K.; Hanus, L. H.; Ploehn, H. J.; Murphy, C. J. Adv. Mater. 1998, 10, 1083. Balogh, L.; Tomalia, D. A. J. Am. Chem. Sec. 1998, 120, 7355. Zhao, M.; Sun, L.; Crooks, R. M. J. Am. Chem. Sec. 1998, 120, 4877.). Here, we report that linear polymer analogues of the dendrimer molecules can be used to make CdS nanocomposites with similar optical properties in solution, albeit with reduced quantum yield of emission. High local concentration of chelating nitrogens on the polymer or dendrimer is hypothesized to be the key feature for ultrasmall, defect-free CdS nanoparticle formation. Immobilization of the nanocomposites in a sol-gel glass is an effective means to capture them in a solid form.