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

Abstract

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. Graphical abstract

The modification of poly(acrylic acid) (PAA) with both N-octylamine (OA) and 5-amino-1-4 pentanol (AP) [PAA–OA–AP] allows for the simultaneous water-solubilization and 5 functionalization of the NCs for applications derived from energy transfer. Highlights ► Poly(acrylic acid) (PAA) has been modified with both N-octylamine (OA) and 5-amino-1-pentanol (AP) [PAA–OA–AP]. ► This modification furnishes a water-soluble and functionalized overcoating for conjugation to CdSe/ZnS nanocrystals (NCs). ► Photophysical studies establish energy transfer between the NC and a conjugated rhodamine isothiocyanate (RITC) dye. ► These properties together establish NC–PAA–OA–AP conjugates as attractive candidates for sensing applications.