Highly Luminescent Cesium Lead Halide Perovskite Nanocrystals with Tunable Composition and Thickness by Ultrasonication

Abstract

We describe the simple, scalable, single-step, and polar-solvent-free synthesis of high-quality colloidal CsPbX (X=Cl, Br, and I) perovskite nanocrystals (NCs) with tunable halide ion composition and thickness by direct ultrasonication of the corresponding precursor solutions in the presence of organic capping molecules. High angle annular dark field scanning transmission electron microscopy (HAADF-STEM) revealed the cubic crystal structure and surface termination of the NCs with atomic resolution. The NCs exhibit high photoluminescence quantum yields, narrow emission line widths, and considerable air stability. Furthermore, we investigated the quantum size effects in CsPbBr and CsPbI nanoplatelets by tuning their thickness down to only three to six monolayers. The high quality of the prepared NCs (CsPbBr ) was confirmed by amplified spontaneous emission with low thresholds. The versatility of this synthesis approach was demonstrated by synthesizing different perovskite NCs.

Advances in Quantum‐Confined Perovskite Nanocrystals for Optoelectronics

“…[17] Recent studies have shown that nanocrystalline perovskites exhibit enhanced PLQYs and offer tunable optical properties not only through their constituent ions but also through their size. [3,[8][9][10][11]15,18,19] Quantum size effects, as illustrated in Figure 1a, have been extensively investigated in conventional semiconductor nanocrystals such as metal chalcogenides and utilized for a wide range of applications during the last two decades. [20] As the size of the nanocrystals approaches the exciton Bohr radius of the material, quantum confinement effects start to influence the excitonic wave function and the energetic states of the exciton, leading to blueshifted photoluminescence (Figure 1a).…”

“…Similarly, perovskite nanocrystals of reduced dimensionality exhibit quantum confinement effects, as shown for the case of nanoplatelets in 2015. [8][9][10]21,22] Despite recent advances, an accurate understanding of thickness-and dimensionality-dependent optical properties of perovskite nanocrystals still proves elusive due to difficulties in the controlled syntheses and characterization of their dimensions. Additionally, while many recent publications present perovskite nanocrystals, most of these show negligible or no quantum confinement.…”

Metal Halide Perovskite Single Crystals: From Growth Process to Application

“…Tong et al reported high-quality colloidal CsPbX 3 (X = I, Br, and Cl) perovskite nanocrystals (NCs) [103]. The synthesis was based on direct tip sonication of precursor mixtures under ambient atmospheric conditions.…”

Dynamic Surface Reconstruction of 2D Ruddlesden-Popper Halide Perovskite under e-Beam Irradiation

“…1. While the electron beam irradiation effect on the 3D halide perovskite materials have been investigated [5][6][7][8][9], studies on 2D halide perovskites are lacking.Herein we present dynamic surface modification on a BA2MA2Pb3I10 (n=3) 2D perovskite with BA (butyl-ammonium, CH3(CH2)3NH3+) working as QW barrier molecules induced by electron beam in transmission electron microscope. We observed various surface dynamics in atomic level under electron irradiation such as lateral growth in c planes of polytypic PbI2 with 3R, 4H and 2H structures at the edge surface of the 2D perovskite accompanied with simultaneous annihilation of surface plane as can be seen in Fig.…”

“…1. While the electron beam irradiation effect on the 3D halide perovskite materials have been investigated [5][6][7][8][9], studies on 2D halide perovskites are lacking.…”