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Nano Research

Article Title

Post-synthesis phase and shape evolution of CsPbBr3 colloidal nanocrystals: The role of ligands

Authors

Elisabetta Fanizza, Dipartimento di Chimica, Università degli Studi di Bari “A. Moro”, Via Orabona 4 , 70126 Bari, Italy CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy
Francesca Cascella, Dipartimento di Chimica, Università degli Studi di Bari “A. Moro”, Via Orabona 4 , 70126 Bari, Italy
Davide Altamura, CNR-Istituto di Cristallografia, Via Amendola, 122/O, 70126 Bari, Italy
Cinzia Giannini, CNR-Istituto di Cristallografia, Via Amendola, 122/O, 70126 Bari, Italy
Annamaria Panniello, CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy
Leonardo Triggiani, Dipartimento di Chimica, Università degli Studi di Bari “A. Moro”, Via Orabona 4 , 70126 Bari, Italy CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy
Francesca Panzarea, Dipartimento di Chimica, Università degli Studi di Bari “A. Moro”, Via Orabona 4 , 70126 Bari, Italy
Nicoletta Depalo, CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy
Roberto Grisorio, Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (DICATECh), Politecnico di Bari, Via Orabona 4, 70125, Italy CNR-NANOTEC- Istituto di Nanotecnologia, Via Monteroni 73100 Lecce, Italy
Gian Paolo Suranna, Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (DICATECh), Politecnico di Bari, Via Orabona 4, 70125, Italy CNR-NANOTEC- Istituto di Nanotecnologia, Via Monteroni 73100 Lecce, Italy
Angela Agostiano, Dipartimento di Chimica, Università degli Studi di Bari “A. Moro”, Via Orabona 4 , 70126 Bari, Italy CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy
M. Lucia Curri, Dipartimento di Chimica, Università degli Studi di Bari “A. Moro”, Via Orabona 4 , 70126 Bari, Italy CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy
Marinella Striccoli, CNR-Istituto per i Processi Chimico Fisici, S. S. Bari, Via Orabona, 4, 70126 Bari, Italy

Keywords

lead halide perovskite nanocrystals, surface chemistry, ligands equilibria, long term stability

Abstract

The surface chemistry of colloidal cesium lead bromide (CsPbBr3) nanocrystals is decisive in determining the stability and the final morphology of this class of materials, characterized by ionic structure and a high defect tolerance factor. Here, the high sensitivity of purified colloidal nanocubes of CsPbBr3 to diverse environmental condition (solvent dilution, ageing, ligands post synthetic treatment) in ambient atmosphere is investigated by means of a comprehensive morphological (electron microscopy), structural (/2 X-ray diffraction (XRD) and grazing incidence wide angle scattering (GIWAXS)), and spectroscopic chemical (1H nuclear magnetic resonance (NMR), nuclear Overhauser effect spectroscopy (NOESY), absorption and emission spectroscopy) characterization. The aging and solvent dilution contribute to modify the nanocrystal morphology, due to a modification of the ligand dynamic. Moreover, we establish the ability of aliphatic carboxylic acids and alkyl amines ligands to induce, even in a post preparative process at room temperature, structural, morphological and spectroscopic variations. Upon post synthesis alkyl amine addition, in particular of oleyl amine and octyl amine, the highly green emitting CsPbBr3 nanocubes effectively turn into one-dimensional (1D) thin tetragonal nanowires or lead halide deficient rhombohedral zero-dimensional (0D) Cs4PbBr6 structures with a complete loss of fluorescence. The addition of an alkyl carboxylic acid, as oleic and nonanoic acid, produces the transformation of nanocubes into still emitting orthorombic two-dimensional (2D) nanoplates. The acid/base equilibrium between the native and added ligands, the adsorbed/free ligands dynamic in solution and the ligand solubility in non-polar solvent contribute to render CsPbBr3 particularly sensitive to environmental and processing conditions and, therefore prone to undergo to structural, morphological and, hence spectroscopic, transformations.

Graphical Abstract

Publisher

Tsinghua University Press

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