Electrostatics enable resonance energy transfer in all-InP quantum dot containing donor–acceptor assembly

Abstract

Light-harvesting studies in donor–acceptor nanohybrid systems based on all-environmentally friendly quantum dots (QDs) are necessary to realize their applications in energy and medical research. Here, we demonstrate an efficient Förster resonance energy transfer (FRET) process in an electrostatically bound all-QD based assembly comprised of indium phosphide/zinc sulfide (InP/ZnS) QDs as both the donor and the acceptor. A perfect control on the speed of nucleation and growth steps, along with appropriate surface functionalization with oppositely charged ligands, enabled an electrostatically bound all-QD donor–acceptor nanohybrid assembly comprising of green- and red-emitting InP/ZnS QDs. Detailed spectroscopic studies revealed the importance of electrostatic attraction in accomplishing an efficient FRET process (∼75%) from donor [+] G-InP/ZnS QDs to acceptor [−] R-InP/ZnS QDs. Further, solid-state studies helped in visualizing the distance-dependent nature of the FRET process at a fixed donor–acceptor ratio. The all-InP QD containing donor–acceptor nanohybrid assembly developed here could find applications in other light-harvesting studies as well, including photovoltaics and photocatalysis.