All-inorganic
cesium lead halide perovskite colloidal nanocrystals
are attractive for next-generation light-emitting diodes because of
their high color purity, but the nonradiative Auger recombination
in perovskite nanocrystal film limits the efficiency and brightness
of the fabricated devices. Here, we introduce a surface-engineering
process to exchange the original long-chain oleic acid/oleylamine
ligands by the cerium–tributylphosphine oxide hybrid ligands
to suppress nonradiative Auger recombination in CsPbBr3 NC film for bright and low-efficiency roll-off light-emitting diodes.
Using ultrafast transient absorption and time-resolved photoluminescence
spectroscopy, we demonstrate that the hybrid ligand passivation can
efficiently remove surface trap states to enhance radiative recombination
and homogenize the exciton concentration to suppress nonradiative
Auger recombination in the CsPbBr3 nanocrystal thin film.
Consequently, we fabricate a light-emitting diode with efficient charge
injection into the CsPbBr3 nanocrystal emitting layer,
achieving a pronounced improvement of electroluminescence with an
external quantum efficiency from 5.5% to 9.1%. More importantly, the
efficiency roll-off characteristics of high-brightness light-emitting
diodes is effectively mitigated. Our reported hybrid ligand passivation
suppressed Auger recombination strategy shows a great potential for
fabricating high-brightness cesium lead halide perovskite light-emitting
diodes.
Herein, three two-dimensional magnetic materials of cobalt(ii) coordination polymers with triangular lattices were synthesized using a mixed benzimidazole–dicarboxylate strategy.
Three cobalt(ii) complexes with diverse structure dimensions based on a mixed benzimidazole–dicarboxylate strategy have been synthesized hydrothermally and characterized structurally and magnetically.
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