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Chemical transformation mechanism for blue-to-green emitting CsPbBr 3 nanocrystals.
- Source :
-
Nanoscale [Nanoscale] 2024 Mar 28; Vol. 16 (13), pp. 6507-6515. Date of Electronic Publication: 2024 Mar 28. - Publication Year :
- 2024
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Abstract
- Recently, metal-halide perovskites have rapidly emerged as efficient light emitters with near-unity quantum yield and size-dependent optical and electronic properties, which have attracted considerable attention from researchers. However, the ultrafast nucleation rate of ionic perovskite counterparts severely limits the in-depth exploration of the growth mechanism of colloidal nanocrystals (NCs). Herein, we used an inorganic ligand nitrosonium tetrafluoroborate (NOBF <subscript>4</subscript> ) to trigger a slow post-synthesis transformation process, converting non-luminescent Cs <subscript>4</subscript> PbBr <subscript>6</subscript> NCs into bright green luminescent CsPbBr <subscript>3</subscript> NCs to elucidate the concrete transformation mechanism via four stages: (i) the dissociation of pristine NCs, (ii) the formation of Pb-Br intermediates, (iii) low-dimensional nanoplatelets (NPLs) and (iv) cubic CsPbBr <subscript>3</subscript> NCs, corresponding to the blue-to-green emission process. The desorption and reorganization of organic ligands induced by NO <superscript>+</superscript> and the involvement of BF <subscript>4</subscript> <superscript>-</superscript> in the ligand exchange process played pivotal roles in this dissolution-recrystallization of NCs. Moreover, controlled shape evolution from anisotropic NPLs to NCs was investigated through variations in the amount of NOBF <subscript>4</subscript> . This further validates that additives exert a decisive role in the symmetry and growth of nanostructured perovskite crystals during phase transition based on the ligand-exchange mechanism. This finding serves as a source of inspiration for the synthesis of highly luminescent CsPbBr <subscript>3</subscript> NCs, providing valuable insights into the chemical mechanism in post-synthesis transformation.
Details
- Language :
- English
- ISSN :
- 2040-3372
- Volume :
- 16
- Issue :
- 13
- Database :
- MEDLINE
- Journal :
- Nanoscale
- Publication Type :
- Academic Journal
- Accession number :
- 38466175
- Full Text :
- https://doi.org/10.1039/d3nr05215j