Energy transfer of CdSe/ZnS nanocrystals encapsulated with rhodamine-dye functionalized poly(acrylic acid)

Energy transfer between a CdSe/ZnS nanocrystal (NC) donor and a rhodamine isothiocyanate (RITC) acceptor has been achieved via a functionalized poly(acrylic acid) (PAA) encapsulating layer over the surface of the NC. The modification of PAA with both N-octylamine (OA) and 5-amino-1-pentanol (AP) [PAA–OA–AP], allows for the simultaneous water-solubilization and functionalization of the NCs, underscoring the ease of synthesizing NC–acceptor conjugates with this strategy. Photophysical studies of the NC–RITC constructs showed that energy transfer is efficient, with kFRET approaching 108 s−1. The ease of the covalent conjugation of molecules to NCs with PAA–OA–AP coating, together with efficient energy transfer, makes the NCs encapsulated with PAA–OA–AP attractive candidates for sensing applications.