The transition from 3D to 2D lead halide perovskites is traditionally led by the lattice incorporation of bulky organic cations. However, the transformation into a coveted 2D superlattice-like structure by cationic substitution at the Pb site of 3D perovskite is unfamiliar. It is demonstrated that the gradual increment of [Sn ] alters the FASn Pb I nanocrystals into the Ruddlesden-Popper-like nanoplatelets (NPLs), with surface-absorbed oleic acid (OA) and oleylamine (OAm) spacer ligand at 80 °C (FA : formamidinium cation). These NPLs are stacked either by a perfect alignment to form the superlattice or by offsetting the NPL edges because of their lateral displacements. The phase transition occurs from the Sn/Pb ratio ≥0.011, with 0.64 wt% of Sn species. At and above Sn/Pb = 0.022, the NPL superlattice stacks start to grow along [00l] with a repeating length of 4.37(3) nm, comprising the organic bilayer and the inorganic block having two octahedral layers (n = 2). Besides, a photoluminescence quantum yield of 98.4% is obtained with Sn/Pb = 0.011 (n ≥ 4), after surface passivation by trioctylphosphine (TOP).
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http://dx.doi.org/10.1002/smll.202304920 | DOI Listing |
Chem Sci
May 2024
Department of Chemical Sciences, Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur 741246 India
Two-dimensional organic-inorganic halide perovskites have emerged as promising candidates for a multitude of optoelectronic technologies, owing to their versatile structure and electronic properties. The optical and electronic properties are harmoniously integrated with both the inorganic metal halide octahedral slab, and the organic spacer layer. The inorganic octahedral layers can also assemble into periodically stacked nanoplatelets, which are interconnected by the organic ammonium cation, resulting in the formation of a superlattice or superstructure.
View Article and Find Full Text PDFJ Am Chem Soc
May 2024
CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.
Chiral superstructures with unique chiroptical properties that are not inherent in the individual units are essential in applications such as 3D displays, spintronic devices, biomedical sensors, and beyond. Generally, chiral superstructures are obtained by tedious procedures exploring various physical and chemical forces to break spatial symmetry during the self-assembly of discrete nanoparticles. In contrast, we herein present a simple and efficient approach to chiral superstructures by intercalating small chiral molecules into preformed achiral superstructures.
View Article and Find Full Text PDFSmall
February 2024
Department of Chemical Sciences, and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, India.
The transition from 3D to 2D lead halide perovskites is traditionally led by the lattice incorporation of bulky organic cations. However, the transformation into a coveted 2D superlattice-like structure by cationic substitution at the Pb site of 3D perovskite is unfamiliar. It is demonstrated that the gradual increment of [Sn ] alters the FASn Pb I nanocrystals into the Ruddlesden-Popper-like nanoplatelets (NPLs), with surface-absorbed oleic acid (OA) and oleylamine (OAm) spacer ligand at 80 °C (FA : formamidinium cation).
View Article and Find Full Text PDFNano Lett
March 2023
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Quantum confined lead halide perovskite nanoplatelets are anisotropic materials displaying strongly bound excitons with spectrally pure photoluminescence. We report the controlled assembly of CsPbBr nanoplatelets through varying the evaporation rate of the dispersion solvent. We confirm the assembly of superlattices in the face-down and edge-up configurations by electron microscopy, as well as X-ray scattering and diffraction.
View Article and Find Full Text PDFCommun Chem
January 2022
Univ. Lyon, ENS de Lyon, CNRS, Laboratoire de Chimie, 69342, Lyon, France.
Semi-conducting nanoplatelets are two-dimensional nanoparticles whose thickness is in the nanometer range and controlled at the atomic level. They have come up as a new category of nanomaterial with promising optical properties due to the efficient confinement of the exciton in the thickness direction. In this perspective, we first describe the various conformations of these 2D nanoparticles which display a variety of bent and curved geometries and present experimental evidences linking their curvature to the ligand-induced surface stress.
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