Beyond Quantum Confinement: Excitonic Nonlocality in Halide Perovskite Nanoparticles with Mie Resonances


Halide perovskite nanoparticles have demonstrated pronounced quantum confinement properties for nanometer-scale sizes and strong Mie resonances for 10 2 nm sizes. Here we studied the intermediate sizes where the nonlocal response of the exciton affects the spectral properties of Mie modes. The mechanism of this effect is associated with the fact that excitons in nanoparticles have an additional kinetic energy that is proportional to k 2 , where k is the wavenumber. Therefore, they possess higher energy than in the case of static excitons. The obtained experimental and theoretical results for MAPbBr 3 nanoparticles of various sizes (2-200 nm) show that for particle radii comparable with the Bohr radius of the exciton (a few nanometers in perovskites), the blue-shift of the photoluminescence, scattering, and absorption cross-section peaks related to quantum confinement should be dominating due to the weakness of Mie resonances for such small sizes. On the other hand, for larger sizes (more than 50-100 nm), the influence of Mie modes increases, and the blue shift remains despite the fact that the effect of quantum confinement becomes much weaker. ©2019 The Royal Society of Chemistry.


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Exciton theory, Stopping power (Nuclear physics), Dynamics, Nanoparticles, Perovskite, Resonance, Absorption cross sections, Halides, Nanoelectromechanical systems, Nuclear size (Physics)

This work was supported by the Ministry of Education and Science of the Russian Federation (Projects 14.Y26.31.0010 for simulations), Russian Science Foundation (17-73-20336 for particles characterization), and by the Research Grant Council of Hong Kong S.A.R. (GRF project CityU 11337616).


©2019 The Royal Society of Chemistry