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Hong–Ou–Mandel interference in colloidal CsPbBr3 perovskite nanocrystals


In the search for novel, robust quantum emitters, inorganic lead halide perovskite nanocrystals have emerged as potential colloidal sources of coherent single photons. While colloidal perovskite nanocrystals offer a great source of synthetically scalable, tunable photon sources, observation of two-photon quantum interference from the emission of any colloidal nanoparticle has not been previously reported. In this work we prepare large CsPbBr3 nanocrystals and observe direct evidence of interference between indistinguishable single photons sequentially emitted from a single nanocrystal. We measure Hong–Ou–Mandel interference from photons in CsPbBr3 nanocrystals, showing corrected visibilities of up to 0.56 ± 0.12 in the absence of any radiative enhancement or photonic architecture. These results demonstrate the unique potential of perovskite nanocrystals to serve as scalable, colloidal sources of indistinguishable single photons.

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Fig. 1: Room-temperature ensemble spectra and HAADF-STEM images of PNCs in this work.
Fig. 2: Photoluminescence, time trace and polarization data.
Fig. 3: Hong–Ou–Mandel interferometry and biexciton filtering.
Fig. 4: Coalescence of indistinguishable photons revealed by correlation functions.

Data availability

All the datasets that support the findings of this study are available on Figshare or from the corresponding author on reasonable request. Source Data are provided with this paper.


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A.E.K.K, C.J.K., W.S., T.S. and D.B.B. acknowledge support from the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award no. DE-SC00216. H.U. acknowledges support from the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (under award no. DE-FG02-07ER46454). T.S. also acknowledges support from Graduate Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC). A.H.P. acknowledges support from a post-doctoral fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC). C.J.K. thanks A. Penn at MIT.nano for assistance with HAADF-STEM measurements, which were performed in part through the use of MIT.nano’s facilities.

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Authors and Affiliations



A.E.K.K. and H.U. conceived of the study. A.E.K.K. designed the experiment, performed sample preparation, acquired all of the single-nanocrystal data and performed all of the data analysis. C.J.K. synthesized the CsPbBr3 perovskite nanocrystals and acquired all of the ensemble data. A.H.P. aided the background research and data interpretation. W.S. assisted in designing the optical set-up and in developing sample preparation procedures. T.S. and D.B.B. helped develop sample preparation procedures. A.E.K.K. wrote the manuscript and all of the authors provided feedback and comments. M.G.B. directed and supervised the research.

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Correspondence to Moungi G. Bawendi.

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Supplementary Discussion and Figs. 1–8.

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Kaplan, A.E.K., Krajewska, C.J., Proppe, A.H. et al. Hong–Ou–Mandel interference in colloidal CsPbBr3 perovskite nanocrystals. Nat. Photon. 17, 775–780 (2023).

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