We correlate spatially resolved fluorescence (-lifetime) measurements with X-ray nanodiffraction to reveal surface defects in supercrystals of self-assembled cesium lead halide perovskite nanocrystals and study their effect on the fluorescence properties. Upon comparison with density functional modeling, we show that a loss in structural coherence, an increasing atomic misalignment between adjacent nanocrystals, and growing compressive strain near the surface of the supercrystal are responsible for the observed fluorescence blueshift and decreased fluorescence lifetimes. Such surface defect-related optical properties extend the frequently assumed analogy between atoms and nanocrystals as so-called quasi-atoms. Our results emphasize the importance of minimizing strain during the self-assembly of perovskite nanocrystals into supercrystals for lighting application such as superfluorescent emitters.
Bibliographical noteFunding Information:
The authors acknowledge DESY (Hamburg, Germany) for the provision of experimental facilities. Parts of this research were carried out at PETRA III synchrotron facility and we would like to thank the beamline staff for assistance in using the Coherence Application P10 beamline. This work was supported by the DFG under grants SCHE1905/8-1(M.S.), SCHE1905/9-1(M.S.), AN680/6-1(D.A.) and SCHR700/38-1(F.S.) as well as the Carl Zeiss Stiftung (Forschungsstrukturkonzept “Interdisziplinäres nanoBCP-Lab”). D.L., D.As., N.M., Y.Y.K. and I.A.V. acknowledge the support of the Helmholtz Associations Initiative Networking Fund (grant No. HRSF-0002) and the Russian Science Foundation (grant No. 18-41-06001). I.A.V. acknowledges the financial support of the Russian Federation represented by the Ministry of Science and Higher Education of the Russian Federation (Agreement No. 075-15-2021-1352). D.L., N.M., D.As., Y.Y.K., M.Sp., and I.A.V. acknowledge support of the project by Edgar Weckert.
© 2022, The Author(s).
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)