title: Spectral properties of multiply charged semiconductor quantum dots.
abstract: Spectrally resolved fluorescence imaging of single CdSe/ZnS quantum dots (QDs), charged by electrospray deposition under negative bias has revealed a surprising net blue shift (∼60 meV peak-to-peak) in the distribution of center frequencies in QD band-edge luminescence. Electrostatic force microscopy (EFM) on the electrospray QD samples showed a subpopulation of charged QDs with 4.7 ± 0.7 excess electrons, as well as a significant fraction of uncharged QDs as evidenced by the distinct cantilever response under bias. We show that the blue-shifted peak recombination energy can be understood as a first-order electronic perturbation that affects the band-edge electron- and hole-states differently. These studies provide new insight into the role of electronic perturbations of QD luminescence by excess charges.
authors: Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States.
authors: Sibel Ebru
authors: SE
authors: Yalcin
authors: Joelle A
authors: JA
authors: Labastide
authors: Danielle L
authors: DL
authors: Sowle
authors: Michael D
authors: MD
authors: Barnes