Retraction Note: Non-blinking semiconductor nanocrystals

Abstract

In this Letter, we reported the unusual non-blinking characteristics of the fluorescence from individual CdZnSe/ZnSe alloyed quantum dots. However, it has recently come to our attention that similar fluorescence behaviour was seen by Celso de Mello Donega, Daniel Vanmaekelbergh and co-workers from a single fluorophore on bare silica glass. In particular, individual fluorescence spots from single molecules were found to be non-blinking, and fluorescence spectra looked similar to what we reported in our Letter. We corroborated their findings by conducting experiments of our own on bare quartz coverslips, and on quartz coverslips coated with polymethyl methacrylate (PMMA). Although these same control experiments were performed by us before publication, this time we clearly observed non-blinking fluorescence from isolated spots on the coverslip. Furthermore, the fluorescence spectra from these spots were in all practical respects identical to what we reported in our Letter. Subsequent investigations by us have revealed that the surprising origins of the unusual fluorescence come from individual, molecular defects in silica glasses, brightened by the polymer coating. The details of these new findings will be the subject of future publications 1 . After examining the data of de Mello Donega and colleagues, and determining that we were both observing the same phenomena, we concluded that we cannot attribute the fluorescence we observed to CdZnSe/ZnSe quantum dots. In view of these new results, we therefore wish to retract the paper and sincerely apologize for our error. All authors agree with the decision to retract the paper with the exception of X.R., who was unable to be contacted.

Accidental Contamination of Substrates and Polymer Films by Organic Quantum Emitters

“…Pending an explanation for the mismatch between this simplistic model fit and the actual spectrum, we point out its striking similarity to the spectra ascribed earlier to various sources. 7,8,20−23,25,26 Moreover, it exhibits a remarkable correspondence with the spectra of individual dyes in PMMA, 27,28 providing a second hint to hydrocarbon molecules as a source for misinterpretation and establishing a link to the visionary association made between the spectra of nonblinking colloidal quantum dots 26 and organic dyes. 29…”

DNA‐Mediated Self‐Assembly of Plasmonic Antennas with a Single Quantum Dot in the Hot Spot

“…This procedure established a spatial correlation between spots exhibiting fluorescence and the scattering signals of the antennas. The matching of fluorescence and DF measurements allows the selective analysis of only those emission spots corresponding to the targeted structures while discarding any potential fluorescent contaminants . From the series of frames obtained in the epifluorescence measurements, we extracted an intensity time trace for each fluorescent spot (Note S5, Supporting Information).…”

“…To further ensure that the fluorescence observed in our antennas originates from individual QDs and not from potential contaminants (e.g., DNA, buffer contaminants), we assembled a control structure consisting of two 40 nm AuNPs spaced by 5 nm without any central particle. The assembly of the control dimers is mediated by a two‐layer DNA origami sheet, which determines the width of the gap (cf.…”

Method to identify and minimize artifacts induced by fluorescent impurities in single-molecule localization microscopy

“… – 3 In recent years new imaging techniques, such as single-molecule localization microscopy (SMLM), 4 – 9 emerge to offer super-resolution single-molecule imaging far beyond the diffraction limit of the light. However, the impact of fluorescent impurities on correctly interpreting single-molecule imaging results has not been thoroughly investigated 10 – 13 …”