Micrometer-Resolution Fluorescence and Lifetime Mappings of CsPbBr 3 Nanocrystal Films Coupled with a TiO 2 Grating
Résumé
Enhancing light emission from perovskite nanocrystal (NC) films is essential in light-emitting devices, as
their conventional stacks often restrict the escape of emitted light. This work addresses this challenge by
employing a TiO2 grating to enhance light extraction and shape the emission of CsPbBr3 nanocrystal films.
Angle-resolved photoluminescence (PL) demonstrated a tenfold increase in emission intensity by coupling the
Bloch resonances of the grating with the spontaneous emission of the perovskite NCs. Fluorescence lifetime
imaging microscopy (FLIM) provided micrometer-resolution mapping of both PL intensity and lifetime across
a large area, revealing a decrease in PL lifetime from 8.2 ns for NC films on glass to 6.1 ns on the TiO2 grating.
Back focal plane (BFP) spectroscopy confirmed how the Bloch resonances transformed the unpolarized,
spatially incoherent emission of NCs into polarized and directed light. These findings provide further insights
into the interactions between dielectric nanostructures and perovskite NC films, offering possible pathways for
designing better performing perovskite optoelectronic devices.
Domaines
Physique [physics]| Origine | Fichiers produits par l'(les) auteur(s) |
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