Comprehensive defect suppression in perovskite nanocrystals for high-efficiency light-emitting diodes
Electroluminescence efficiencies of metal halide perovskite nanocrystals (PNCs) are limited by a lack of material strategies that can both suppress the formation of defects and enhance the charge carrier confinement. Here we report a one-dopant alloying strategy that generates smaller, monodisperse...
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Veröffentlicht in: | Nature photonics 2021-02, Vol.15 (2), p.148-155 |
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Hauptverfasser: | , , , , , , , , , , , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Electroluminescence efficiencies of metal halide perovskite nanocrystals (PNCs) are limited by a lack of material strategies that can both suppress the formation of defects and enhance the charge carrier confinement. Here we report a one-dopant alloying strategy that generates smaller, monodisperse colloidal particles (confining electrons and holes, and boosting radiative recombination) with fewer surface defects (reducing non-radiative recombination). Doping of guanidinium into formamidinium lead bromide PNCs yields limited bulk solubility while creating an entropy-stabilized phase in the PNCs and leading to smaller PNCs with more carrier confinement. The extra guanidinium segregates to the surface and stabilizes the undercoordinated sites. Furthermore, a surface-stabilizing 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene was applied as a bromide vacancy healing agent. The result is highly efficient PNC-based light-emitting diodes that have current efficiency of 108 cd A
−1
(external quantum efficiency of 23.4%), which rises to 205 cd A
−1
(external quantum efficiency of 45.5%) with a hemispherical lens.
Guanidinium doping is shown to enhance the operation of perovskite nanocrystal light-emitting diodes. |
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ISSN: | 1749-4885 1749-4893 |
DOI: | 10.1038/s41566-020-00732-4 |