Dilution-Induced Formation of Hybrid Perovskite Nanoplatelets.
Yu TongFlorian EhratWillem VanderlindenCarlos Cardenas-DawJacek K StolarczykLakshminarayana PolavarapuAlexander S UrbanPublished in: ACS nano (2016)
Perovskite nanocrystals (NCs) are an important extension to the fascinating field of hybrid halide perovskites. Showing significantly enhanced photoluminescence (PL) efficiency and emission wavelengths tunable through halide content and size, they hold great promise for light-emitting applications. Despite the rapid advancement in this field, the physical nature and size-dependent excitonic properties have not been well investigated due to the challenges associated with their preparation. Herein we report the spontaneous formation of highly luminescent, quasi-2D organic-inorganic hybrid perovskite nanoplatelets (NPls) upon dilution of a dispersion of bulk-like NCs. The fragmentation of the large NCs is attributed to osmotic swelling induced by the added solvent. An excess of organic ligands in the solvent quickly passivates the newly formed surfaces, stabilizing the NPls in the process. The thickness of the NPls can be controlled both by the dilution level and by the ligand concentration. Such colloidal NPls and their thin films were found to be extremely stable under continuous UV light irradiation. Full tunability of the NPl emission wavelength is achieved by varying the halide ion used (bromide, iodide). Additionally, time-resolved PL measurements reveal an increasing radiative decay rate with decreasing thickness of the NPls, likely due to an increasing exciton binding energy. Similarly, measurements on iodide-containing NPls show a transformation from biexponential to monoexponential PL decay with decreasing thickness, likely due to an increasing fraction of excitonic recombination. This interesting phenomenon of change in fluorescence upon dilution is a result of the intricate nature of the perovskite material itself and is uncommon in inorganic materials. Our findings enable the synthesis of halide perovskite NCs with high quantum efficiency and good stability as well as a tuning of both their optical and morphological properties.
Keyphrases
- solar cells
- energy transfer
- light emitting
- liquid chromatography tandem mass spectrometry
- optical coherence tomography
- room temperature
- gas chromatography
- liquid chromatography
- quantum dots
- water soluble
- mental health
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- single cell
- simultaneous determination
- mass spectrometry
- diffusion weighted imaging
- dna repair
- single molecule
- ms ms
- biofilm formation
- loop mediated isothermal amplification
- pseudomonas aeruginosa
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- solid state
- sensitive detection
- deep learning
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- magnetic resonance imaging
- solid phase extraction
- oxidative stress
- genome wide
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- atomic force microscopy
- candida albicans