Direct probe of spectral inhomogeneity reveals synthetic tunability of single-nanocrystal spectral linewidths


The spectral linewidth of an ensemble of fluorescent emitters is dictated by the combination of single-emitter linewidths and sample inhomogeneity. For semiconductor nanocrystals, efforts to tune ensemble linewidths for optical applications have focused primarily on eliminating sample inhomogeneities, because conventional single-molecule methods cannot reliably build accurate ensemble-level statistics for single-particle linewidths. Photon-correlation Fourier spectroscopy in solution (S-PCFS) offers a unique approach to investigating single-nanocrystal spectra with large sample statistics and high signal-to-noise ratios, without user selection bias and at fast timescales. With S-PCFS, we directly and quantitatively deconstruct the ensemble linewidth into contributions from the average single-particle linewidth and from sample inhomogeneity. We demonstrate that single-particle linewidths vary significantly from batch to batch and can be synthetically controlled. These findings delineate the synthetic challenges facing underdeveloped nanomaterials such as InP and InAs core–shell particles and introduce new avenues for the synthetic optimization of fluorescent nanoparticles.

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Figure 1: Experimental set-up.
Figure 2: Demonstration of S-PCFS data analysis.
Figure 3: Comparison of different core materials' composition.
Figure 4: Comparison of samples with CdSe cores.


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This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (award no. DE-FG02-07ER46454) and by the National Institutes of Health through the MIT Laser Biomedical Resource Center (award no. P41EB015871-26A1). J.C. acknowledges support from the National Science Foundation Graduate Research Fellowship Program. D.D.W. acknowledges support from the Fannie and John Hertz Foundation. The authors thank QD Vision for providing the InP core–shell sample and J. Cordero for help with synthesis.

Author information




J.C., L.F.M., X.B. and M.G.B. conceived and designed the experiments. J.C. performed the S-PCFS experiments. O.C. and D.K.H. synthesized the CdSe–CdS and InAs–ZnS nanoparticles. D.D.W. and O.C. performed TEM. J.C. and A.P.B. analysed the data with guidance from L.F.M., X.B. and M.G.B. The manuscript was written by J.C. and A.P.B. with contributions from all authors.

Corresponding author

Correspondence to Moungi G. Bawendi.

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Cui, J., Beyler, A., Marshall, L. et al. Direct probe of spectral inhomogeneity reveals synthetic tunability of single-nanocrystal spectral linewidths. Nature Chem 5, 602–606 (2013).

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