ZnX2 mediated post-synthetic transformation of zero dimensional Cs4PbBr6 nanocrystals for opto-electronic applications

Sharma, Sumit; Mamgain, Swati; Attarwala, Burhanuddin; Yella, Aswani

doi:10.1039/c9na00244h

Cited by 11 publications

(11 citation statements)

References 39 publications

(45 reference statements)

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“…For example, a hot-injection approach that employed OA and OAm as the capping ligands, and set a Cs-rich environment have been successfully used to synthesize Cs 4 PbBr 6 NCs. [22,26,[104][105][106][107] Compared to the preparation of CsPbX 3 NCs, [2] Cs 4 PbX 6 always required an excess of Cs precursor and a lower reaction temperature. Synthesis of Cs 4 PbBr 6 involved the dissolution of PbX 2 in octadecene (ODE), OA and OAm in a vial at ≈150 °C.…”

Section: Hot-injectionmentioning

confidence: 99%

Low‐Dimensional‐Networked Cesium Lead Halide Perovskites: Properties, Fabrication, and Applications

et al. 2020

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resistance against thermal-treatment compared to organic-inorganic hybrid lead halide perovskites (MAPbX 3 and FAPbX 3), due to the high thermal decomposition temperature of inorganic cations, thus drawing much attention. Owing to their impressive features, all-inorganic lead halide perovskites have been greatly useful in photovoltaic and optoelectronic applications, including solar cells, light-emitting diodes (LEDs), lasers, photodetectors and photocatalysis. [5-17] The conspicuous achievements in CsPbX 3 provoke the rapid development of its derivatives, Cs 4 PbX 6 and CsPb 2 X 5. These Cs x Pb y X z materials are composed of the same element compositions and [PbX 6 ] 4− unit cells. However, they possess completely different connectivity characters of [PbX 6 ] 4− octahedrons. CsPbX 3 is classified as a type of 3D perovskite, because [PbX 6 ] 4− octahedra are corner-shared along all three axes, while CsPb 2 X 5 has a sandwich-like arrangement with Cs + cations in between PbX 2 crystallographic planes, which can be regarded as a 2D phase. In Cs 4 PbX 6 , disconnected [PbBr 6 ] 4− octahedra are completely decoupled by Cs + cations. Among these three structures, CsPb 2 X 5 and Cs 4 PbX 6 , with dimensional-network less than 3 are referred to as lowdimensional-networked cesium lead halide perovskites. Besides the connectivity, these structures can be understood from a confinement perspective. CsPbX 3 is not confined in any dimension such that it can be considered as a 3D networked semiconductor. CsPb 2 X 5 and Cs 4 PbX 6 are confined in one dimension and all three dimensions, hence the name 2D and 0D structures, respectively. [18,19] In CsPb 2 X 5 and Cs 4 PbX 6 , the excitons cannot dissociate easily within all dimensions; instead, they are confined in the PbX 2 planes and individual [PbX 6 ] 4− units, respectively, resulting in larger bandgaps compared to the traditional ABX 3 phase. Figure 1 illustrates these three structures with different dimensions. Until now, comprehensive accounts of these Cs x Pb y X z materials have been made. However, most recent research focuses on CsPbX 3 , which has excellent optical properties and promising potential in various applications. Its derivatives, CsPb 2 X 5 and Cs 4 PbX 6 have achieved tremendous progress but are still far behind that of CsPbX 3. Many problems still seriously limit the rapid development of these low-dimensional-networked perovskites, a typical one being the debate on the origin of their luminescence. In this Review article, we focus on Cs 4 PbX 6 and CsPb 2 X 5 , and attempt to unveil their features, potential in All-inorganic cesium lead halide perovskites have emerged as promising optoelectronic materials with excellent photophysical properties and great potential in a variety of applications. In parallel with the most investigated CsPbX 3 , its derivates, Cs 4 PbX 6 and CsPb 2 X 5 , with low-dimensional-networked structures have also attracted great attention. In this review, recent advancements on the low-dimensional-networked cesium lead halide perovs...

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Section: Hot-injectionmentioning

confidence: 99%

Low‐Dimensional‐Networked Cesium Lead Halide Perovskites: Properties, Fabrication, and Applications

et al. 2020

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“…As a counter cation, quaternary ammonium cation (C 8 H 17 ) 4 N + produced by addition of tetraoctylammonium bromide (TOAB) formed an ion pair with oleic acid (OA), which in turn reduced the ligand density of OA at the surface of CsPbBr 3 nanocubes and triggered their oriented attachment at the water–oil surface. However, direct evidence such as TEM data visualizing this oriented attachment process was not provided in this study, [ 10b ] and the interpretation of the rod‐shaped perovskite NCs as a cubic structure requires further investigation.…”

Section: Crystal Structures Of Metal Halide Perovskite Nanorodsmentioning

confidence: 97%

“…However, Jing et al. [ 10b ] reported the growth of cubic phase CsPbBr 3 NRs by attaching CsPbBr 3 nanocubes along the [100] direction of the cubic structure through a chemical transformation of polyhedral Cs 4 PbBr 6 NCs at the water–oil interface. As a counter cation, quaternary ammonium cation (C 8 H 17 ) 4 N + produced by addition of tetraoctylammonium bromide (TOAB) formed an ion pair with oleic acid (OA), which in turn reduced the ligand density of OA at the surface of CsPbBr 3 nanocubes and triggered their oriented attachment at the water–oil surface.…”

Section: Crystal Structures Of Metal Halide Perovskite Nanorodsmentioning

confidence: 99%

“…[ 40 ] Sharma et al. [ 10a ] demonstrated that the treatment of 0D Cs 4 PbBr 6 NCs using ZnI 2 salt resulted in the formation of CsPbBr 3 NRs. This transformation took place through the surface modification of Cs 4 PbBr 6 NCs with Zn 2+ ions, followed by the extraction of excess Cs + ions.…”

Section: Growth Mechanisms Of Perovskite Nanorodsmentioning

confidence: 99%

“…Although there are a few documented attempts for the controlled chemical growth of perovskite NRs, [ 6b,7a,10 ] research into this area is still in its infancy. A high‐degree of control during the synthesis of perovskite NRs in terms of size, aspect ratio, and performance, is not yet been fully realized.…”

Section: Introductionmentioning

confidence: 99%

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Metal Halide Perovskite Nanorods: Shape Matters

et al. 2020

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have a soft and ionic lattice. [3] Such ionic nature makes it possible to conduct anion exchange reactions from one kind of perovskite NCs, for example CsPbBr 3 , to another and thus achieve particles with different compositions such as CsPbCl 3 , CsPbI 3 , and their mixed-anion alloys, which is changing to accomplish for conventional semiconductor NCs. This enables bandgap tuning over the whole visible and even near-infrared spectral ranges while maintaining the size and morphology of the resulting NCs. [4] However, their ionic nature also makes the growth rates of perovskites extremely fast, with a completion of the NC growth ranging from less than a second to a couple of seconds. [5] The fast growth rate makes it difficult to control the final shape of perovskite NCs, [6] which will be elaborated upon in detail in this article further below. Useful properties of 1D semiconductor nanorods (NRs) including linearly polarized light emission, reduced lasing threshold, and improved charge transport [6] make them stand out from semiconductor NCs of other morphologies in a variety of applications such as liquid crystal displays (LCDs), lasers, solar cells and photocatalysis. [7] For example, aligned CdSe/CdS NRs incorporated in thin polymer films have been proposed as optical enhancement films to improve the brightness and broaden the color gamut of LCDs. [7b-d] In addition, CdSe/CdS, alloyed CdSe x S 1−x and CsPbBr 3 NRs have demonstrated a relatively low amplified spontaneous emission (ASE) threshold and a high net optical gain at a medium or low pump intensity, making them capable of producing lasing with low pumping thresholds. [7a,8] Furthermore, the 1D character of semiconductor NRs benefits efficient charge separation and provides specific spatial locations for selective deposition of other materials to realize 1D heterostructures, with prominent potentials in optoelectronics and photocatalysis. [9] Although there are a few documented attempts for the controlled chemical growth of perovskite NRs, [6b,7a,10] research into this area is still in its infancy. A high-degree of control during the synthesis of perovskite NRs in terms of size, aspect ratio, and performance, is not yet been fully realized. It is desirable to develop facile, robust, and scalable synthetic strategies for the preparation of high-quality perovskite NRs, to enrich the existing knowledge of their growth mechanisms, and to improve their optical and electronic properties that underpin their future applications. Quasi-1D metal halide perovskite nanorods (NRs) are emerging as a type of materials with remarkable optical and electronic properties. Research into this field is rapidly expanding and growing in the past several years, with significant advances in both mechanistic studies of their growth and widespread possible applications. Here, the recent advances in 1D metal halide perovskite nanocrystals (NCs) are reviewed, with a particular emphasis on NRs. At first, the crystal structures of perovskites are elaborated, which is followed by a revi...

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Zn (II)‐Doped Cesium Copper Halide Nanocrystals with High Quantum Yield and Colloidal Stability for High‐Resolution X‑Ray Imaging

Ran

et al. 2023

Advanced Optical Materials

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and adjustable bandgap, thereby exhibiting extraordinary X-ray detection performance. [1] To date, high-quality lead-based perovskite single crystals have demonstrated ultrahigh detection performance. However, they are limited by their current shortcomings, including the toxicity of lead, chemical instability, inherent brittleness of bulk crystals, and their hightemperature fabrication and complex processes. [2] Therefore, the development of low-cost, environmentally friendly, flexible X-ray detectors, and novel scintillators still remain a challenge.Owing to the high emission stability, low self-absorption, soft lattice, unique self-trapped exciton emission (STE), [3] and relatively low toxicity and earth-abundant composition, lead-free copper-based halide Cs 3 Cu 2 I 5 nanocrystals (NCs) have attracted extensive attention in the field of optoelectronics, [4] such as electroluminescent lightemitting diode (LED) devices, [5] ultraviolet (UV) photodetectors, [6] X-ray imaging, [7] and anticounterfeiting technology. [8] Although progress has been made in the synthesis and application of Cs 3 Cu 2 I 5 NCs, [9] the insufficient synthesis reaction and difficulty in controlling the crystal size, morphology, and uniformity of Cs 3 Cu 2 I 5 NCs still remain the main obstacles hindering device performance and fundamental research. [10] Metal ion doping is an effective way to tune the structure and optoelectronic properties of materials, which Scintillators are essential for high-energy radiation detection in a variety of potential applications. However, due to complex fabrication processes and nanocrystal homogeneity, conventional scintillators are challenging to meet the need for cost-effective, environmentally friendly, and flexible X-ray detection. Here, monodisperse nanocrystals (NCs) with small grain size and colloidal stability are obtained by adjusting the doping concentration of Zn 2+ ions and controlling the morphology uniformity of Cs 3 Cu 2 I 5 NCs. The photoluminescence quantum yield (PLQY) for the optimal doping concentration is as high as 92.8%, which is a 28.5% improvement compared to nondoped NCs. Density functional theory calculations reveal that the Zn 2+ dopant inclines to occupy Cu sites and the I-rich condition suppresses the formation of I vacancy, enriching the excited electron density at the band-edge to enhance the self-trapped exciton emission. Moreover, high luminescence performance and flexible X-ray scintillator films are prepared using Zn 2+doped Cs 3 Cu 2 I 5 NCs, with a spatial resolution of up to 15.7 lp mm -1 . This work provides an effective strategy for the development of environmentally friendly, low-cost, and efficient blue-emitting 0D all-inorganic metal halides, as well as shows their great potential for high-performance flexible lead-free and low-toxicity X-ray detector applications.

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ZnX₂ mediated post-synthetic transformation of zero dimensional Cs₄PbBr₆ nanocrystals for opto-electronic applications

Abstract: Herein we demonstrate a facile approach for the synthesis of all inorganic cesium lead halide perovskite nanocrystal composites CsPbX3 (X = Cl, Br, I) with high quantum yield by post-synthetic modulation of zero dimensional Cs4PbBr6 nanocrystals with ZnX2 salts.

Cited by 11 publications

References 39 publications

Low‐Dimensional‐Networked Cesium Lead Halide Perovskites: Properties, Fabrication, and Applications

Low‐Dimensional‐Networked Cesium Lead Halide Perovskites: Properties, Fabrication, and Applications

Metal Halide Perovskite Nanorods: Shape Matters

Zn (II)‐Doped Cesium Copper Halide Nanocrystals with High Quantum Yield and Colloidal Stability for High‐Resolution X‑Ray Imaging

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