Rational Fabrication of Arrays of Plasmonic Metal–Quantum Dot Sandwiched Nanodisks with Enhanced Förster Resonance Energy Transfer

Abstract

The size-dependent optical gap due to the quantum confinement effect is a hallmark of semiconductor quantum dots (QDs). A major research effort underway is to control energy transfer in QDs for diverse applications ranging from solar energy harvesting to fluorescent displays and biological imaging. In this work, we report an innovative approach for fabricating monodispersed arrays of Au/polymer/QDs sandwiched nanodisks on a wafer scale with high rationality and reproducibility. Via template-assisted assembling of QDs, the plasmonic Au nanodisk can be precisely coupled to a defined number of QD clusters. Using steady-state and time-resolved photoluminescence spectroscopy, we studied the enhancement of Förster resonance energy transfer (FRET) rate between donor and acceptor QDs coupled with plasmonic resonance of the Au nanodisks. By systematically increasing the spectral overlap of the acceptor QD emission with plasmonic resonance, we demonstrated that the donor lifetime decreases monotonically and FRET rate increases significantly. The results suggest a viable route to fabricate precisely controlled plasmonic–QD coupled nanoentities and to enhance energy transfer at the nanoscale.