1
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Kim YH, Yoon SY, Yang H. Blue-Emissive ZnSeTe Quantum Dots and Their Electroluminescent Devices. J Phys Chem Lett 2024; 15:2142-2151. [PMID: 38364081 DOI: 10.1021/acs.jpclett.4c00070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
Over the last two decades, quantum-dot light-emitting diodes (QLEDs), also known as quantum dot (QD) electroluminescent devices, have gained prominence in next-generation display technologies, positioning them as potential alternatives to organic light-emitting diodes. Nonetheless, challenges persist in enhancing key device performances such as efficiency and lifetime, while those of blue QLEDs lag behind compared with green and red counterparts. In this Perspective, we discuss key factors affecting the photoluminescence characteristics of environmentally benign blue-emissive ternary ZnSeTe QDs, including composition, core/shell heterostructure, and surface ligand. Notably, we highlight the recent progress in breakthrough strategies to enhance blue QLED performance, examining the effects of the ZnSeTe QD attribute and device architecture on device performance. This Perspective offers insights into integrated aspects of QD material and device structure in overcoming challenges toward a high-performance blue ZnSeTe QLED.
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Affiliation(s)
- Yang-Hee Kim
- Department of Materials Science and Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Suk-Young Yoon
- Department of Materials Science and Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Heesun Yang
- Department of Materials Science and Engineering, Hongik University, Seoul 04066, Republic of Korea
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2
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Baek H, Kang S, Heo J, Choi S, Kim R, Kim K, Ahn N, Yoon YG, Lee T, Chang JB, Lee KS, Park YG, Park J. Insights into structural defect formation in individual InP/ZnSe/ZnS quantum dots under UV oxidation. Nat Commun 2024; 15:1671. [PMID: 38396037 PMCID: PMC10891109 DOI: 10.1038/s41467-024-45944-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
InP/ZnSe/ZnS quantum dots (QDs) stand as promising candidates for advancing QD-organic light-emitting diodes (QLED), but low emission efficiency due to their susceptibility to oxidation impedes applications. Structural defects play important roles in the emission efficiency degradation of QDs, but the formation mechanism of defects in oxidized QDs has been less investigated. Here, we investigated the impact of diverse structural defects formation on individual QDs and propagation during UV-facilitated oxidation using high-resolution (scanning) transmission electron microscopy. UV-facilitated oxidation of the QDs alters shell morphology by the formation of surface oxides, leaving ZnSe surfaces poorly passivated. Further oxidation leads to the formation of structural defects, such as dislocations, and induces strain at the oxide-QD interfaces, facilitating In diffusion from the QD core. These changes in the QD structures result in emission quenching. This study provides insight into the formation of structural defects through photo-oxidation, and their effects on emission properties of QDs.
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Grants
- IBS-R006-D1 Institute for Basic Science (IBS)
- This work was supported by the Institute for Basic Science (IBS-R006-D1) (H.B., S.K., and J.P.) and Samsung Display Co., Ltd (H.B., S.K., J.H., S.C., R.K., K.K., N.A., Y.-G.Y., T.L., J.B.C., K.S.L., Y.-G.P., and J.P.). H.B. and J.P. acknowledge support from Samsung Research Funding & Incubation Center of Samsung Electronics under Project Number SRFC-MA2002-3. H.B. and S.K.
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Affiliation(s)
- Hayeon Baek
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea
| | - Sungsu Kang
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea
| | - Junyoung Heo
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Soonmi Choi
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Ran Kim
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Kihyun Kim
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Nari Ahn
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Yeo-Geon Yoon
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Taekjoon Lee
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Jae Bok Chang
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Kyung Sig Lee
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea
| | - Young-Gil Park
- Samsung Display Co., Ltd., Yongin-si, Gyeonggi-do, Republic of Korea.
| | - Jungwon Park
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea.
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea.
- Institute of Engineering Research, College of Engineering, Seoul National University, Seoul, Republic of Korea.
- Advanced Institute of Convergence Technology, Seoul National University, Suwon, Republic of Korea.
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3
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Long Z, Yang G, Shao R, Chen Z, Liu Y, Liu R, Zhong H. The Strain Effects and Interfacial Defects of Large ZnSe/ZnS Core/Shell Nanocrystals. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306602. [PMID: 37705120 DOI: 10.1002/smll.202306602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Indexed: 09/15/2023]
Abstract
The shell growth of large ZnSe/ZnS nanocrystals( is of great importance in the pursuit of pure-blue emitters for display applications, however, suffers from the challenges of spectral blue-shifts and reduced photoluminescence quantum yields. In this work, the ZnS shell growth on different-sized ZnSe cores is investigated. By controlling the reactivity of Zn and S precursors, the ZnS shell growth can be tuned from defect-related strain-released to defect-free strained mode, corresponding to the blue- and red-shifts of resultant nanocrystals respectively. The shape of strain-released ZnSe/ZnS nanocrystals can be kept nearly spherical during the shell growth, while the shape of strained nanocrystals evolutes from spherical into island-like after the critical thickness. Furthermore, the strain between ZnSe core and ZnS shell can convert the band alignment from type-I into type-II core/shell structure, resulting in red-shifts and improved quantum yield. By correlating the strain effects with interfacial defects, a strain-released shell growth model is proposed to obtain large ZnSe/ZnS nanocrystals with isotropic shell morphology.
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Affiliation(s)
- Zhiwei Long
- National Engineering Research Center for Rare Earth, GRIREM Advanced Materials Co. Ltd., General Research Institute for Nonferrous Metals, Beijing, 100088, China
- MIIT Key Laboratory for Low-dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Gaoling Yang
- MIIT Key Laboratory for Low-dimensional Quantum Structure and Devices, School of Optics and Photonics, Beijing Institute of Technology, Beijing, 100081, China
| | - Ruiwen Shao
- Beijing Advanced Innovation Center for Intelligent Robots and Systems and School of Medical Technology, Beijing Institute of Technology, Beijing, 100081, China
| | - Zhuo Chen
- BOE Technology Group Co., Ltd, Beijing, 100176, China
| | - Yang Liu
- BOE Technology Group Co., Ltd, Beijing, 100176, China
| | - Ronghui Liu
- National Engineering Research Center for Rare Earth, GRIREM Advanced Materials Co. Ltd., General Research Institute for Nonferrous Metals, Beijing, 100088, China
| | - Haizheng Zhong
- MIIT Key Laboratory for Low-dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081, China
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4
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Cavanaugh P, Wang X, Bautista MJ, Jen-La Plante I, Kelley DF. Spectral widths and Stokes shifts in InP-based quantum dots. J Chem Phys 2023; 159:134704. [PMID: 37787140 DOI: 10.1063/5.0165956] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 09/12/2023] [Indexed: 10/04/2023] Open
Abstract
InP-based quantum dots (QDs) have Stokes shifts and photoluminescence (PL) line widths that are larger than in II-VI semiconductor QDs with comparable exciton energies. The mechanisms responsible for these spectral characteristics are investigated in this paper. Upon comparing different semiconductors, we find the Stokes shift decreases in the following order: InP > CdTe > CdSe. We also find that the Stokes shift decreases with core size and decreases upon deposition of a ZnSe shell. We suggest that the Stokes shift is largely due to different absorption and luminescent states in the angular momentum fine structure. The energy difference between the fine structure levels, and hence the Stokes shifts, are controlled by the electron-hole exchange interaction. Luminescence polarization results are reported and are consistent with this assignment. Spectral widths are controlled by the extent of homogeneous and inhomogeneous broadening. We report PL and PL excitation (PLE) spectra that facilitate assessing the roles of homogeneous and different inhomogeneous broadening mechanisms in the spectra of zinc-treated InP and InP/ZnSe/ZnS particles. There are two distinct types of inhomogeneous broadening: size inhomogeneity and core-shell interface inhomogeneity. The latter results in a distribution of core-shell band offsets and is caused by interfacial dipoles associated with In-Se or P-Zn bonding. Quantitative modeling of the spectra shows that the offset inhomogeneity is comparable to but somewhat smaller than the size inhomogeneity. The combination of these two types of inhomogeneity also explains several aspects of reversible hole trapping dynamics involving localized In3+/VZn2- impurity states in the ZnSe shells.
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Affiliation(s)
- Paul Cavanaugh
- Department of Chemistry and Biochemistry, University of California Merced, 5200 North Lake Road, Merced, California 95343, USA
| | - Xudong Wang
- Nanosys, Inc., 233 S. Hillview Dr., Milpitas, California 95035, USA
| | - Maria J Bautista
- Nanosys, Inc., 233 S. Hillview Dr., Milpitas, California 95035, USA
| | | | - David F Kelley
- Department of Chemistry and Biochemistry, University of California Merced, 5200 North Lake Road, Merced, California 95343, USA
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5
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Nguyen HA, Sharp D, Fröch JE, Cai YY, Wu S, Monahan M, Munley C, Manna A, Majumdar A, Kagan CR, Cossairt BM. Deterministic Quantum Light Arrays from Giant Silica-Shelled Quantum Dots. ACS APPLIED MATERIALS & INTERFACES 2023; 15:4294-4302. [PMID: 36507852 DOI: 10.1021/acsami.2c18475] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Colloidal quantum dots (QDs) are promising candidates for single-photon sources with applications in photonic quantum information technologies. Developing practical photonic quantum devices with colloidal materials, however, requires scalable deterministic placement of stable single QD emitters. In this work, we describe a method to exploit QD size to facilitate deterministic positioning of single QDs into large arrays while maintaining their photostability and single-photon emission properties. CdSe/CdS core/shell QDs were encapsulated in silica to both increase their physical size without perturbing their quantum-confined emission and enhance their photostability. These giant QDs were then precisely positioned into ordered arrays using template-assisted self-assembly with a 75% yield for single QDs. We show that the QDs before and after assembly exhibit antibunching behavior at room temperature and their optical properties are retained after an extended period of time. Together, this bottom-up synthetic approach via silica shelling and the robust template-assisted self-assembly offer a unique strategy to produce scalable quantum photonics platforms using colloidal QDs as single-photon emitters.
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Affiliation(s)
- Hao A Nguyen
- Department of Chemistry, University of Washington, Seattle, Washington 98189, United States
| | - David Sharp
- Department of Physics, University of Washington, Seattle, Washington 98185, United States
| | - Johannes E Fröch
- Department of Physics, University of Washington, Seattle, Washington 98185, United States
- Department of Electrical and Computer Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Yi-Yu Cai
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Shenwei Wu
- Department of Chemistry, University of Washington, Seattle, Washington 98189, United States
| | - Madison Monahan
- Department of Chemistry, University of Washington, Seattle, Washington 98189, United States
| | - Christopher Munley
- Department of Physics, University of Washington, Seattle, Washington 98185, United States
| | - Arnab Manna
- Department of Physics, University of Washington, Seattle, Washington 98185, United States
| | - Arka Majumdar
- Department of Physics, University of Washington, Seattle, Washington 98185, United States
- Department of Electrical and Computer Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Cherie R Kagan
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98189, United States
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6
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Li M, Tang W, Gong J. Unusual shape-preserved pathway of a core-shell phase transition triggered by orientational disorder. IUCRJ 2023; 10:38-51. [PMID: 36598501 PMCID: PMC9812221 DOI: 10.1107/s2052252522011034] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/17/2022] [Indexed: 05/29/2023]
Abstract
The ubiquitous presence of crystal defects provides great potential and opportunities to construct the desired structure (hence with the desired properties) and tailor the synthetic process of crystalline materials. However, little is known about their regulation role in phase transition and crystallization pathways. It was generally thought that a phase transition in solution proceeds predominantly via the solvent-mediated phase-transformation pathway due to energetically high-cost solid-state phase transitions (if any). Herein, we report an unprecedented finding that an orientational disorder defect present in the crystal structure triggers an unusual pathway of a core-shell phase transition with apparent shape-preserved evolution. In the pathway, the solid-state dehydration phase transition occurs inside the crystal prior to its competitive transformation approach mediated by solvent, forming an unconventional core-shell structure. Through a series of combined experimental and computational techniques, we revealed that the presence of crystal defects, introduced by urate tautomerism over the course of crystallization, elevates the metastability of uric acid dihydrate (UAD) crystals and triggers UAD dehydration to the uric acid anhydrate (UAA) phase in the crystal core which precedes with surface dissolution of the shell UAD crystal and recrystallization of the core phase. This unique phase transition could also be related to defect density, which appears to be influenced by the thickness of UAD crystals and crystallization driving force. The discovery of an unusual pathway of the core-shell phase transition suggests that the solid-state phase transition is not necessarily slower than the solvent-mediated phase transformation in solution and provides an alternative approach to constructing the core-shell structure. Moreover, the fundamental role of orientational disorder defects on the phase transition identified in this study demonstrates the feasibility to tailor phase transition and crystallization pathways by strategically importing crystal defects, which has broad applications in crystal engineering.
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Affiliation(s)
- Mengya Li
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
- Collaborative Innovation Center of Chemistry Science and Engineering, Tianjin 300072, People’s Republic of China
| | - Weiwei Tang
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
- Collaborative Innovation Center of Chemistry Science and Engineering, Tianjin 300072, People’s Republic of China
- Key Laboratory Modern Drug Delivery and High Efficiency, Tianjin University, Tianjin 300072, People’s Republic of China
| | - Junbo Gong
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
- Collaborative Innovation Center of Chemistry Science and Engineering, Tianjin 300072, People’s Republic of China
- Key Laboratory Modern Drug Delivery and High Efficiency, Tianjin University, Tianjin 300072, People’s Republic of China
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7
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Chakraborty S, Grandhi GK, Viswanatha R. Study of the Interface and Radial Dopant Position in Semiconductor Heterostructures Using X-ray Absorption Spectroscopy. J Phys Chem Lett 2022; 13:11036-11043. [PMID: 36413658 DOI: 10.1021/acs.jpclett.2c02704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two questions that remain a challenge in the field of colloidal doped core/shell nanomaterials of different morphologies are the nature of the interface and the radial location of the dopant ion due to the diffusion within the lattice. Using a model system of Cu-doped CdSe/CdS quantum dots, we develop an in-depth understanding of the extended X-ray absorption fine structure (EXAFS) spectra of the dopant and host atoms to address both issues. Our findings suggest that the interface is not sharp, in agreement with the nonstructural studies in the literature. Local structure analysis around the Cu dopant ion confirms that Cu drifts out from the core toward the outer region in the absence of the shell but stays mostly in the core after the formation of a sufficiently thick interfacial barrier (∼2 monolayers). This study highlights the significance of EXAFS spectroscopy in understanding the nature of the interface in nanomaterials.
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8
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Nemoto K, Watanabe J, Sun HT, Shirahata N. Coherent InP/ZnS core@shell quantum dots with narrow-band green emissions. NANOSCALE 2022; 14:9900-9909. [PMID: 35781556 DOI: 10.1039/d2nr02071h] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We report, for the first time, that the coherent growth of zinc sulfide (ZnS) on a colloidal indium phosphide (InP) quantum dot (QD) yields a InP/ZnS core/shell structure with a single lattice constant of 0.563 nm. Compared to the bulk crystal of zinc-blend (cubic) InP, the lattice of the core QD is compressed by 4.1%. In contrast, the lattice of the shell expands by 4.1% relative to the bulky ZnS crystal throughout the core/shell QD if the shell is thinner than or equal to 0.81 nm and the diameter of the core QD is smaller than 2.64 nm. Under these conditions, the bandgap of the core QD increases, resulting in a blueshift of absorption and photoluminescence (PL) spectra. The PL peak is centered at 523 nm. Furthermore, the PL quantum yield is enhanced up to 70% and the PL bandwidth narrows to 36 nm based on the strengthened quantum confinement effect. The temperature dependence of the PL properties is investigated to discuss the effect of the core/shell lattice coherency on the improved PL performances.
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Affiliation(s)
- Kazuhiro Nemoto
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
| | - Junpei Watanabe
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.
- Department of Physics, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
| | - Hong-Tao Sun
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.
| | - Naoto Shirahata
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
- Department of Physics, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
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9
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Van Avermaet H, Schiettecatte P, Hinz S, Giordano L, Ferrari F, Nayral C, Delpech F, Maultzsch J, Lange H, Hens Z. Full-Spectrum InP-Based Quantum Dots with Near-Unity Photoluminescence Quantum Efficiency. ACS NANO 2022; 16:9701-9712. [PMID: 35709384 DOI: 10.1021/acsnano.2c03138] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Photoluminescent color conversion by quantum dots (QDs) makes possible the formation of spectrum-on-demand light sources by combining blue LEDs with the light generated by a specific blend of QDs. Such applications, however, require a near-unity photoluminescence quantum efficiency since self-absorption magnifies disproportionally the impact of photon losses on the overall conversion efficiency. Here, we present a synthesis protocol for forming InP-based QDs with +90% quantum efficiency across the full visible spectrum from blue/cyan to red. The central features of our approach are as follows: (1) the formation of InP core QDs through one-batch-one-size reactions based on aminophosphine as the phosphorus precursor, (2) the introduction of a core/shell/shell InP/Zn(Se,S)/ZnS structure, and (3) the use of specific interfacial treatments, most notably the saturation of the ZnSe surface with zinc acetate prior to ZnS shell growth. Moreover, we adapted the composition of the Zn(Se,S) inner shell to attain the intended emission color while minimizing line broadening induced by the InP/ZnS lattice mismatch. The protocol is established by analysis of the QD composition and structure using multiple techniques, including solid-state nuclear magnetic resonance spectroscopy and Raman spectroscopy, and verified for reproducibility by having different researchers execute the same protocol. The realization of full-spectrum, +90% quantum efficiency will strongly facilitate research into light-matter interaction in general and luminescent color conversion in particular through InP-based QDs.
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Affiliation(s)
- Hannes Van Avermaet
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Gent 9000, Belgium
| | - Pieter Schiettecatte
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Gent 9000, Belgium
| | - Sandra Hinz
- Institute of Physical Chemistry, Universität Hamburg, Hamburg 20146, Germany
- Institute of Condensed Matter Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Luca Giordano
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Gent 9000, Belgium
| | - Fabio Ferrari
- Laboratoire de Physique et Chimie des Nano-Objets, Université de Toulouse, CNRS, INSA, UPS, Toulouse CEDEX-4 31077, France
| | - Céline Nayral
- Laboratoire de Physique et Chimie des Nano-Objets, Université de Toulouse, CNRS, INSA, UPS, Toulouse CEDEX-4 31077, France
| | - Fabien Delpech
- Laboratoire de Physique et Chimie des Nano-Objets, Université de Toulouse, CNRS, INSA, UPS, Toulouse CEDEX-4 31077, France
| | - Janina Maultzsch
- Institute of Condensed Matter Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Holger Lange
- Institute of Physical Chemistry, Universität Hamburg, Hamburg 20146, Germany
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Gent 9000, Belgium
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10
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Liu G, Liang W, Xue X, Rosei F, Wang Y. Atomic Identification of Interfaces in Individual Core@shell Quantum Dots. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2102784. [PMID: 34647434 PMCID: PMC8596122 DOI: 10.1002/advs.202102784] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/22/2021] [Indexed: 05/29/2023]
Abstract
CdSe@CdS Core@shell quantum dots (QDs) have been widely studied in recent years, due to their architecture which allows to tailor properties by controlling structure and composition. However, since CdSe and CdS have the same crystal structure, same cations, and similar lattice parameters, it is very challenging to image the interface. Herein, high-resolution transmission electron microscopy, high-angle annular dark-field imaging, and energy-dispersive X-ray spectroscopy elemental mapping are combined to characterize the core@shell structure and identify the interface in the CdSe@CdS QDs with different CdS shell thicknesses. By examining changes in lattice spacing in an individual CdSe@CdS quantum dot, the atomic core@shell interface is identified. For thin-shelled QDs, an ideal coherent interface forms between core and shell due to the small lattice mismatch, and the lattice spacing remains unchanged at the core and shell regions. For thick-shelled QDs, the lattice spacing is different at the core and shell regions, while the heterostructured interface is still coherent and cannot be clearly imaged. As the shell thickness further increases, a sharp core@shell interface appears. The results define an approach to characterize the heterostructure of two materials with the same crystalline structure and cations.
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Affiliation(s)
- Guiju Liu
- College of Physics & State Key LaboratoryQingdao UniversityNo. 308 Ningxia RoadQingdao266071P. R. China
| | - Wenshuang Liang
- College of Physics & State Key LaboratoryQingdao UniversityNo. 308 Ningxia RoadQingdao266071P. R. China
| | - Xuyan Xue
- College of Physics & State Key LaboratoryQingdao UniversityNo. 308 Ningxia RoadQingdao266071P. R. China
| | - Federico Rosei
- Centre Énergie Matériaux et TélécommunicationsInstitut National de la Recherche Scientifique1650 Boulevard Lionel‐BouletVarennesQuébecJ3X 1S2Canada
| | - Yiqian Wang
- College of Physics & State Key LaboratoryQingdao UniversityNo. 308 Ningxia RoadQingdao266071P. R. China
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11
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Prudnikau A, Shiman DI, Ksendzov E, Harwell J, Bolotina EA, Nikishau PA, Kostjuk SV, Samuel IDW, Lesnyak V. Design of cross-linked polyisobutylene matrix for efficient encapsulation of quantum dots. NANOSCALE ADVANCES 2021; 3:1443-1454. [PMID: 36132870 PMCID: PMC9418506 DOI: 10.1039/d0na01012j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/19/2021] [Indexed: 05/08/2023]
Abstract
Photoluminescent quantum dots (QDs) are a prominent example of nanomaterials used in practical applications, especially in light-emitting and light-converting devices. Most of the current applications of QDs require formation of thin films or their incorporation in solid matrices. The choice of an appropriate host material capable of preventing QDs from degradation and developing a process of uniform incorporation of QDs in the matrix have become essential scientific and technological challenges. In this work, we developed a method of uniform incorporation of Cu-Zn-In-S (CZIS) QDs into a highly protective cross-linked polyisobutylene (PIB) matrix with high chemical resistance and low gas permeability. Our approach involves the synthesis of a methacrylate-terminated three-arm star-shaped PIB oligomeric precursor capable of quick formation of a robust 3D polymer network upon exposure to UV-light, as well as the design of a special ligand introducing short PIB chains onto the surface of the QDs, thus providing compatibility with the matrix. The obtained cross-linked QDs-in-polymer composites underwent a complex photostability test in air and under vacuum as well as a chemical stability test. These tests found that CZIS QDs in a cross-linked PIB matrix demonstrated excellent photo- and chemical stability when compared to identical QDs in widely used polyacrylate-based matrices. These results make the composites developed excellent materials for the fabrication of robust, stable and durable transparent light conversion layers.
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Affiliation(s)
- Anatol Prudnikau
- Physical Chemistry, TU Dresden Zellescher Weg 19 01069 Dresden Germany
| | - Dmitriy I Shiman
- Research Institute for Physical Chemical Problems of the Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
| | - Evgenii Ksendzov
- Physical Chemistry, TU Dresden Zellescher Weg 19 01069 Dresden Germany
- Research Institute for Physical Chemical Problems of the Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
| | - Jonathon Harwell
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews North Haugh St Andrews Fife KY16 9SS UK
| | - Ekaterina A Bolotina
- Physical Chemistry, TU Dresden Zellescher Weg 19 01069 Dresden Germany
- Research Institute for Physical Chemical Problems of the Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
- Department of Chemistry, Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
| | - Pavel A Nikishau
- Research Institute for Physical Chemical Problems of the Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
| | - Sergei V Kostjuk
- Research Institute for Physical Chemical Problems of the Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University 119991 Moscow Russia
- Department of Chemistry, Belarusian State University Leningradskaya Str. 14 220006 Minsk Belarus
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews North Haugh St Andrews Fife KY16 9SS UK
| | - Vladimir Lesnyak
- Physical Chemistry, TU Dresden Zellescher Weg 19 01069 Dresden Germany
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12
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Zhao J, Chen B, Wang F. Shedding Light on the Role of Misfit Strain in Controlling Core-Shell Nanocrystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004142. [PMID: 33051904 DOI: 10.1002/adma.202004142] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/21/2020] [Indexed: 05/17/2023]
Abstract
Heteroepitaxial modification of nanomaterials has become a powerful means to create novel functionalities for various applications. One of the most elementary factors in heteroepitaxial nanostructures is the misfit strain arising from mismatched lattices of the constituent parts. Misfit strain not only dictates epitaxy kinetics for diversifying nanocrystal morphologies but also provides rational control over materials properties. In recent years, advances in chemical synthesis along with the rapid development of electron microscopy and X-ray diffraction techniques have enabled a substantial understanding of strain-related processes, which offers theoretical foundation and experimental guidance for researchers to refine heteroepitaxial nanostructures and their properties. Herein, recent investigations on heterogeneous core-shell nanocrystals containing misfit strains are summarized, with a focus on the mechanistic understanding of strain and strain-induced effects such as tuning the epitaxial habit, modulating the optical emission, and enhancing the catalytic activity and magnetic coercivity.
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Affiliation(s)
- Jianxiong Zhao
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Bing Chen
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Feng Wang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
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13
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Liu J, Zhang J. Nanointerface Chemistry: Lattice-Mismatch-Directed Synthesis and Application of Hybrid Nanocrystals. Chem Rev 2020; 120:2123-2170. [DOI: 10.1021/acs.chemrev.9b00443] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jia Liu
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, P.R. China
| | - Jiatao Zhang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, P.R. China
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14
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Jin X, Xie K, Zhang T, Lian H, Zhang Z, Xu B, Li D, Li Q. Cation exchange assisted synthesis of ZnCdSe/ZnSe quantum dots with narrow emission line widths and near-unity photoluminescence quantum yields. Chem Commun (Camb) 2020; 56:6130-6133. [DOI: 10.1039/d0cc01302a] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
ZnCdSe/ZnSe quantum dots reveal a notable FWHM of 17.1 nm with a near-unity PL QY at 631 nm.
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Affiliation(s)
- Xiao Jin
- Key Laboratory of Clean Energy Materials Chemistry of Guangdong Higher Education Institutes
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
| | - Kanlin Xie
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
| | - Tingting Zhang
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
| | - Huada Lian
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
| | - Zhenghe Zhang
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
| | - Bing Xu
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
| | - Dongyu Li
- Key Laboratory of Clean Energy Materials Chemistry of Guangdong Higher Education Institutes
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
| | - Qinghua Li
- Key Laboratory of Clean Energy Materials Chemistry of Guangdong Higher Education Institutes
- Lingnan Normal University
- Zhanjiang 524048
- P. R. China
- Key Laboratory of Environmentally Friendly Functional Materials and Devices
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15
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Jang EP, Han CY, Lim SW, Jo JH, Jo DY, Lee SH, Yoon SY, Yang H. Synthesis of Alloyed ZnSeTe Quantum Dots as Bright, Color-Pure Blue Emitters. ACS APPLIED MATERIALS & INTERFACES 2019; 11:46062-46069. [PMID: 31746194 DOI: 10.1021/acsami.9b14763] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Considering a strict global environmental regulation, fluorescent quantum dots (QDs) as key visible emitters in the next-generation display field should be compositionally non-Cd. When compared to green and red emitters obtainable from size-controlled InP QDs, development of non-Cd blue QDs remains stagnant. Herein, we explore the synthesis of non-Cd, ZnSe-based QDs with binary and ternary compositions toward blue photoluminescence (PL). First, the size increment of binary ZnSe QDs is attempted by a multiply repeated growth until blue PL is attained. Although this approach offers a relevant blue color, excessively large-sized ZnSe QDs inevitably entail a low PL quantum yield. As an alternative strategy to the above size enlargement, the alloying of high-band gap ZnSe with lower-band gap ZnTe in QD synthesis is carried out. These alloyed ternary ZnSeTe QDs after ZnS shelling exhibit a systematically tunable PL of 422-500 nm as a function of Te/Se ratio. Analogous to the state-of-the-art heterostructure of InP QDs with a double-shelling scheme, an inner shell of ZnSe is newly inserted with different thicknesses prior to an outer shell of ZnS, where the effects of the thickness of ZnSe inner shell on PL properties are examined. Double-shelled ZnSeTe/ZnSe/ZnS QDs with an optimal thickness of the ZnSe inner shell are then employed for all-solution-processed fabrication of a blue QD light-emitting diode (QLED). The present blue QLED as the first ZnSeTe QD-based device yields a peak luminance of 1195 cd/m2, a current efficiency of 2.4 cd/A, and an external quantum efficiency of 4.2%, corresponding to the record values reported from non-Cd blue devices.
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Affiliation(s)
- Eun-Pyo Jang
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Chang-Yeol Han
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Seung-Won Lim
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Jung-Ho Jo
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Dae-Yeon Jo
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Sun-Hyoung Lee
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Suk-Young Yoon
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
| | - Heesun Yang
- Department of Materials Science and Engineering , Hongik University , Seoul 04066 , Korea
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16
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McBride JR, Rosenthal SJ. Real colloidal quantum dot structures revealed by high resolution analytical electron microscopy. J Chem Phys 2019; 151:160903. [DOI: 10.1063/1.5128366] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- James R. McBride
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, Tennessee 37235, USA
| | - Sandra J. Rosenthal
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, Tennessee 37235, USA
- Department of Interdisciplinary Materials Science, Department of Chemical and Biomolecular Engineering, Department of Physics and Astronomy, Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37235, USA
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17
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Lattice Strain Analysis of a Mn-Doped CdSe QD System Using Crystallography Techniques. Processes (Basel) 2019. [DOI: 10.3390/pr7100639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this work, we report on the different sizes of manganese-doped cadmium selenide quantum dots (Mn-doped CdSe QDs) synthesized for 0 to 90 min using a reverse micelle organic solvent method and surfactant having a zinc blende structure, with physical size varying from 3 to 14 nm and crystallite size from 2.46 to 5.46 nm and with a narrow size distribution. At similar reaction times, Mn-doped CdSe QDs displayed the growth of larger QDs compared with the pure CdSe QDs. Due to the implementation of lattice strain owing to the inclusion of Mn atoms in the CdSe QD lattice, the lattice parameter was compressed as the QD size increased. Strain was induced by the particle size reduction, as observed from X-ray diffractometer (XRD) analysis. The analyses of the strain effect on the QD reduction are discussed relative to each of the XRD characteristics.
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18
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Lim M, Lee W, Bang G, Lee WJ, Park Y, Kwon Y, Jung Y, Kim S, Bang J. Synthesis of far-red- and near-infrared-emitting Cu-doped InP/ZnS (core/shell) quantum dots with controlled doping steps and their surface functionalization for bioconjugation. NANOSCALE 2019; 11:10463-10471. [PMID: 31112192 DOI: 10.1039/c9nr02192b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In this study, we designed and synthesized far-red- and near-infrared-emitting Cu-doped InP-based quantum dots (QDs), and we also demonstrated their highly specific and sensitive biological imaging ability. Cu-doped InP/ZnS (core/shell) QDs were prepared using the hot colloidal synthesis method in the organic phase. The ZnS shell passivates the surface and improves the photoluminescence (PL) intensity. However, the InP : Cu/ZnS (core : dopants/shell) QDs, which were obtained after the Cu dopant was incorporated into bare InP QDs, followed by ZnS shell coating, had relatively low PL intensities (maximum PL quantum yield (QY) was only ∼16%) presumably due to the formation of defect sites in the InP-core QDs caused by dopant migration from the InP core to the ZnS shell. We prepared high-quality InP/ZnS : Cu/ZnS (core/shell : dopant/outer-shell) QDs, where thin ZnS shell layers were grown on bare InP QDs prior to Cu ion doping to prevent dopant migration and obtained PL QYs as high as 40%. The native hydrophobic ligands of the as-synthesized Cu-doped QDs were replaced with hydrophilic ligands including dihydrolipoic acid and a zwitterionic ligand, which rendered the QDs water-soluble. These QDs exhibited remarkable colloidal stabilities over a wide pH range, with hydrodynamic diameters less than 10 nm. Modified QD surfaces can also be used in conjugation with other functional moieties to apply highly specific and sensitive imaging probes with very low background levels. As a proof-of-concept study, we successfully demonstrated the selective imaging of streptavidin beads with biotin-conjugated QDs. These decorated Cu-doped InP/ZnS (core/shell) QDs are promising biological-probe candidates for imaging and assaying with reduced concerns regarding toxicity.
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Affiliation(s)
- Mihye Lim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Namgu, Pohang 37673, Republic of Korea.
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19
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Singhal P, Pulhani V. Effect of Ligand Concentration, Dilution, and Excitation Wavelength on the Emission Properties of CdSe/CdS Core Shell Quantum Dots and Their Implication on Detection of Uranium. ChemistrySelect 2019. [DOI: 10.1002/slct.201900792] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Pallavi Singhal
- Environmental Monitoring and Assessment DivisionBhabha Atomic Research Centre Mumbai 400085 India
| | - Vandana Pulhani
- Environmental Monitoring and Assessment DivisionBhabha Atomic Research Centre Mumbai 400085 India
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20
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Reid KR, McBride JR, La Croix AD, Freymeyer NJ, Click SM, Macdonald JE, Rosenthal SJ. Role of Surface Morphology on Exciton Recombination in Single Quantum Dot-in-Rods Revealed by Optical and Atomic Structure Correlation. ACS NANO 2018; 12:11434-11445. [PMID: 30403844 DOI: 10.1021/acsnano.8b06472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The physical structure of colloidal quantum dot (QD) nanostructures strongly influences their optical and electronic behavior. A fundamental understanding of this interplay between structure and function is crucial to fully tailor the performance of QDs and their assemblies. Here, by directly correlating the atomic and chemical structure of single CdSe-CdS quantum dot-in-rods with time-resolved fluorescence measurements on the same structures, we identify morphological irregularities at their surfaces that moderate photoluminescence efficiencies. We find that two nonradiative exciton recombination mechanisms are triggered by these imperfections: charging and trap-assisted nonradiative processes. Furthermore, we show that the proximity of the surface defects to the CdSe core of the core-shell structures influences whether the charging or trap-assisted nonradiative channel dominates exciton recombination. Our results extend to other QD nanostructures and emphasize surface roughness as a crucial parameter when designing colloidal QDs with specific excitonic fates.
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21
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Xu J, Tu D, Zheng W, Shang X, Huang P, Cheng Y, Wang Y, Chen X. Interfacial Defects Dictated In Situ Fabrication of Yolk-Shell Upconversion Nanoparticles by Electron-Beam Irradiation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1800766. [PMID: 30356918 PMCID: PMC6193145 DOI: 10.1002/advs.201800766] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/29/2018] [Indexed: 05/05/2023]
Abstract
Homogeneous core-shell structured nanoparticles (NPs) are prevailingly designed to accommodate lanthanide emitters, and such an epitaxial shell deposited on core NP is generally believed to help eliminate surface traps or defects on the as-prepared core. However, upon electron-beam irradiation to core-shell-shell NaLuF4:Gd/Yb/Er@NaLuF4:Nd/Yb@NaLuF4 upconversion NPs (UCNPs), it is revealed that interfacial defects actually exist at the core-shell and shell-shell interfaces, even with a higher density than the bulk-phase defects in inner core. Because of such higher density of interfacial defects, the kinetic energies transferred from energetic electrons to atoms may trigger the faster Na/F atom ejections and outward atom migrations in the coating layers than in the inner core of NPs, which ultimately results in the in situ formation of novel yolk-shell UCNPs. These findings provide new insights into interfacial defects in homogeneous core-shell structured NaLnF4 NPs, and pave the way toward utilizing the interactions of high-energy particles with materials for in situ fabrication of novel nanostructures.
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Affiliation(s)
- Jin Xu
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Datao Tu
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Wei Zheng
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Xiaoying Shang
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Ping Huang
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Yao Cheng
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Yuansheng Wang
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
| | - Xueyuan Chen
- CAS Key Laboratory of Design and Assembly of Functional NanostructuresState Key Laboratory of Structural Chemistry,and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian350002China
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22
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Abstract
Transient absorption (TA) and time-resolved photoluminescence (PL) spectroscopies have been used to provide direct spectroscopic evidence for the recently reported phenomenon of thermal "surface charging" in II-VI quantum dots (QDs). In these studies, zincblende CdSe cores are synthesized by standard methods, and a thin CdS shell deposited by the decomposition of Cd(DDTC)2, resulting in core/shell QDs with chalcogenide-rich surfaces. Following ligand exchange with oleylamine, these QDs have empty low-lying surface states that can be thermally populated from the valence band. At room temperature, the surface charging equilibrium results in some fraction of the particles having a hole in the valence band, i.e., the surface acceptor states make the particle p-type. Photoexcitation of the surface charged state results in what is essentially a positive trion, which can undergo a fast Auger recombination. Both PL and TA (bleach recovery) kinetics of the CdSe/CdS QDs show a 70 ps decay component, which is assigned to Auger recombination. The empty nonbonding surface orbitals are passivated by ligation with a trialkylphosphine, and the fast decay component is absent when tributylphosphine is present. The comparison of the TA and PL kinetics shows that the relative amplitude of the 70 ps component is a factor of about 1.5 greater in the TA than in the PL. They also show that the fast component in the PL spectrum is shifted about 6 nm to the blue of the exciton luminescence. The above observations can be understood in terms of the trion versus exciton spectroscopy and strongly support the assignment of the 70 ps transient to the decay of a trion formed from the surface charged state.
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Affiliation(s)
- David Morgan
- Chemistry and Chemical Biology , University of California Merced , 5200 North Lake Road , Merced , California 95343 , United States
| | - David F Kelley
- Chemistry and Chemical Biology , University of California Merced , 5200 North Lake Road , Merced , California 95343 , United States
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23
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Demortière A, Leonard DN, Petkov V, Chapman K, Chattopadhyay S, She C, Cullen DA, Shibata T, Pelton M, Shevchenko EV. Strain-Driven Stacking Faults in CdSe/CdS Core/Shell Nanorods. J Phys Chem Lett 2018; 9:1900-1906. [PMID: 29589949 DOI: 10.1021/acs.jpclett.8b00914] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Colloidal semiconductor nanocrystals are commonly grown with a shell of a second semiconductor material to obtain desired physical properties, such as increased photoluminescence quantum yield. However, the growth of a lattice-mismatched shell results in strain within the nanocrystal, and this strain has the potential to produce crystalline defects. Here, we study CdSe/CdS core/shell nanorods as a model system to investigate the influence of core size and shape on the formation of stacking faults in the nanocrystal. Using a combination of high-angle annular dark-field scanning transmission electron microscopy and pair-distribution-function analysis of synchrotron X-ray scattering, we show that growth of the CdS shell on smaller, spherical CdSe cores results in relatively small strain and few stacking faults. By contrast, growth of the shell on larger, prolate spheroidal cores leads to significant strain in the CdS lattice, resulting in a high density of stacking faults.
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Affiliation(s)
- Arnaud Demortière
- Center for Nanoscale Materials , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
- Laboratoire de Réactivité et Chimie des Solides (LRCS), CNRS UMR 7314 , Université Picardie Jules Verne , 80039 Amiens , France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), CNRS FR 3459 , 80039 Amiens , France
| | - Donovan N Leonard
- Materials Science and Technology Division , Oak Ridge National Laboratory , 1 Bethel Valley Road , Oak Ridge , Tennessee 37831-6071 , United States
| | - Valeri Petkov
- Department of Physics , Central Michigan University , Mount Pleasant , Michigan 48859 , United States
| | - Karena Chapman
- Advanced Photon Source , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Soma Chattopadhyay
- Advanced Photon Source , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Chunxing She
- Center for Nanoscale Materials , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - David A Cullen
- Materials Science and Technology Division , Oak Ridge National Laboratory , 1 Bethel Valley Road , Oak Ridge , Tennessee 37831-6071 , United States
| | - Tomohiro Shibata
- Advanced Photon Source , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Matthew Pelton
- Center for Nanoscale Materials , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
- Department of Physics , University of Maryland, Baltimore County (UMBC) , Baltimore , Maryland 21250 , United States
| | - Elena V Shevchenko
- Center for Nanoscale Materials , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
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24
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Singhal P, Jha SK, Vats BG, Ghosh HN. Electron-Transfer-Mediated Uranium Detection Using Quasi-Type II Core-Shell Quantum Dots: Insight into Mechanistic Pathways. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8114-8122. [PMID: 28749681 DOI: 10.1021/acs.langmuir.7b00926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Uranium is one of the most toxic and important elements present in the environment, and because of its high toxicity, ultra-trace-level detection is of utmost importance. Many methods were reported earlier for this purpose, but each has its own limitations such as high cost, sophisticated instrumentation, sample processing, and so forth. Herein we have demonstrated an alternate method that is much simpler and can be used for the ultra-trace-level detection of uranium. We have synthesized 3-mercaptopropionic acid (MPA)-capped CdSe/CdS core-shell quantum dots (CSQDs) and used its photoluminescence properties to detect uranium in solution. Steady-state emission studies suggest the luminescence quenching of CSQDs in the presence of uranium. Redox levels of CSQDs and uranium suggests that the electron-transfer process from photoexcited CSQDs to uranium is a thermodynamically viable process, which has subsequently been confirmed by time-resolved studies. A Stern-Volmer plot of CSQDs with uranium suggests that the detection limit of this method is 74.5 ppb. The method has an advantage over other reported methods for being simple and low cost and requiring a small amout of sample processing. To the best of our knowledge, we are reporting for the first time uranium detection using quasi-type II CSQDs and proposing the mechanistic path through luminescence spectroscopy, which in turn helps us to design an efficient detection method.
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Affiliation(s)
| | - Sanjay K Jha
- Homi Bhabha National Institute , Mumbai 400094, India
| | | | - Hirendra N Ghosh
- Institute of Nano Science and Technology , Habitat Centre Mohali, Punjab 160062, India
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25
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Razgoniaeva N, Moroz P, Yang M, Budkina DS, Eckard H, Augspurger M, Khon D, Tarnovsky AN, Zamkov M. One-Dimensional Carrier Confinement in "Giant" CdS/CdSe Excitonic Nanoshells. J Am Chem Soc 2017; 139:7815-7822. [PMID: 28535356 DOI: 10.1021/jacs.7b02054] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The emerging generation of quantum dot optoelectronic devices offers an appealing prospect of a size-tunable band gap. The confinement-enabled control over electronic properties, however, requires nanoparticles to be sufficiently small, which leads to a large area of interparticle boundaries in a film. Such interfaces lead to a high density of surface traps which ultimately increase the electrical resistance of a solid. To address this issue, we have developed an inverse energy-gradient core/shell architecture supporting the quantum confinement in nanoparticles larger than the exciton Bohr radius. The assembly of such nanostructures exhibits a relatively low surface-to-volume ratio, which was manifested in this work through the enhanced conductance of solution-processed films. The reported core/shell geometry was realized by growing a narrow gap semiconductor layer (CdSe) on the surface of a wide-gap core material (CdS) promoting the localization of excitons in the shell domain, as was confirmed by ultrafast transient absorption and emission lifetime measurements. The band gap emission of fabricated nanoshells, ranging from 15 to 30 nm in diameter, has revealed a characteristic size-dependent behavior tunable via the shell thickness with associated quantum yields in the 4.4-16.0% range.
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Affiliation(s)
| | | | | | | | | | - Marissa Augspurger
- Department of Chemistry and Biochemistry, St. Mary's University , San Antonio, Texas 78228, United States
| | - Dmitriy Khon
- Department of Chemistry and Biochemistry, St. Mary's University , San Antonio, Texas 78228, United States
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26
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Wang N, Koh S, Jeong BG, Lee D, Kim WD, Park K, Nam MK, Lee K, Kim Y, Lee BH, Lee K, Bae WK, Lee DC. Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability. NANOTECHNOLOGY 2017; 28:185603. [PMID: 28393764 DOI: 10.1088/1361-6528/aa6828] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present facile synthesis of bright CdS/CdSe/CdS@SiO2 nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO2 is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO2 shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO2 and SQW/SiO2 is over 80% and SQW/SiO2 shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO2-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO2 nanoparticles in bio-labeling or display applications.
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Affiliation(s)
- Nianfang Wang
- Department of Chemical and Bimolecular Engineering (BK21+ Program), KAIST Institute for the Nanocentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
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Jang Y, Shapiro A, Isarov M, Rubin-Brusilovski A, Safran A, Budniak AK, Horani F, Dehnel J, Sashchiuk A, Lifshitz E. Interface control of electronic and optical properties in IV–VI and II–VI core/shell colloidal quantum dots: a review. Chem Commun (Camb) 2017; 53:1002-1024. [DOI: 10.1039/c6cc08742f] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Core/shell heterostructures provide controlled optical properties, tuneable electronic structure, and chemical stability due to an appropriate interface design.
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Liao C, Xu R, Xu Y, Zhang C, Xiao M, Zhang L, Lu C, Cui Y, Zhang J. Ultralow-Threshold Single-Mode Lasing from Phase-Pure CdSe/CdS Core/Shell Quantum Dots. J Phys Chem Lett 2016; 7:4968-4976. [PMID: 27973873 DOI: 10.1021/acs.jpclett.6b02465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The development of colloidal quantum dot (QD) lasers is blocked by Auger recombination (AR). Here, phase-pure wurtzite CdSe/CdS core/shell QDs with controlled shell thickness are reported, which possess nearly defect-free core/shell interfaces. Benefiting from increased volume, electron-hole partial spatial separation, and nearly defect-free alloyed interface, this series of QDs exhibit a greater than 3 orders of magnitude decrease in AR rates with increasing shell thickness. Consequently, the amplified spontaneous emission threshold of the QDs with an 11 monolayer CdS shell is found to reach a minimum of 16 μJ cm-2. A record long lifetime (>1000 ps) and extraordinarily large bandwidth (>170 nm) of optical gain are observed by employing ultrafast transient absorption spectroscopy. We leverage the low-threshold gain of the QDs to fabricate microlasers that display single-mode operation and an ultralow threshold of ∼2 μJ cm-2. Our results represent a valuable step toward practical QD lasers.
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Affiliation(s)
- Chen Liao
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Ruilin Xu
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Yanqing Xu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Lei Zhang
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Changgui Lu
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Yiping Cui
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Jiayu Zhang
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
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Jeong BG, Park YS, Chang JH, Cho I, Kim JK, Kim H, Char K, Cho J, Klimov VI, Park P, Lee DC, Bae WK. Colloidal Spherical Quantum Wells with Near-Unity Photoluminescence Quantum Yield and Suppressed Blinking. ACS NANO 2016; 10:9297-9305. [PMID: 27690386 DOI: 10.1021/acsnano.6b03704] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Thick inorganic shells endow colloidal nanocrystals (NCs) with enhanced photochemical stability and suppression of photoluminescence intermittency (also known as blinking). However, the progress of using thick-shell heterostructure NCs in applications has been limited due to the low photoluminescence quantum yield (PL QY ≤ 60%) at room temperature. Here, we demonstrate thick-shell NCs with CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) geometry that exhibit near-unity PL QY at room temperature and suppression of blinking. In SQW NCs, the lattice mismatch is diminished between the emissive CdSe layer and the surrounding CdS layers as a result of coherent strain, which suppresses the formation of misfit defects and consequently permits ∼100% PL QY for SQW NCs with a thick CdS shell (≥5 nm). High PL QY of thick-shell SQW NCs is preserved even in concentrated dispersion and in film under thermal stress, which makes them promising candidates for applications in solid-state lightings and luminescent solar concentrators.
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Affiliation(s)
- Byeong Guk Jeong
- Department of Chemical and Biomolecular Engineering, KAIST Institute for the Nanocentury, Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Young-Shin Park
- Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
- Center for High Technology Materials, University of New Mexico , Albuquerque, New Mexico 87131, United States
| | - Jun Hyuk Chang
- School of Chemical and Biological Engineering, The National Creative Research Initiative Center for Intelligent Hybrids, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Ikjun Cho
- Department of Chemical and Biological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jai Kyeong Kim
- Photoelectronic Hybrids Research Center, Korea Institute of Science and Technology (KIST) , 14-gil 5 Hwarang-ro, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Heesuk Kim
- Photoelectronic Hybrids Research Center, Korea Institute of Science and Technology (KIST) , 14-gil 5 Hwarang-ro, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Kookheon Char
- School of Chemical and Biological Engineering, The National Creative Research Initiative Center for Intelligent Hybrids, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jinhan Cho
- Department of Chemical and Biological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Philip Park
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Doh C Lee
- Department of Chemical and Biomolecular Engineering, KAIST Institute for the Nanocentury, Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Wan Ki Bae
- Photoelectronic Hybrids Research Center, Korea Institute of Science and Technology (KIST) , 14-gil 5 Hwarang-ro, Seongbuk-gu, Seoul 02792, Republic of Korea
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Beane GA, Gong K, Kelley DF. Auger and Carrier Trapping Dynamics in Core/Shell Quantum Dots Having Sharp and Alloyed Interfaces. ACS NANO 2016; 10:3755-3765. [PMID: 26895220 DOI: 10.1021/acsnano.6b00370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The role of interface sharpness in controlling the excited state dynamics in CdSe/ZnSe core/shell particles is examined here. Particles composed of CdSe/ZnSe with 2.4-4.0 nm diameter cores and approximately 4 monolayer shells are synthesized at relatively low temperature, ensuring a sharp core-shell interface. Subsequent annealing results in cadmium and zinc interdiffusion, softening the interface. TEM imaging and absorption spectra reveal that annealing results in no change in the particle sizes. Annealing results in a 5-10 nm blue shift in the absorption spectrum, which is compared to calculated spectral shifts to characterize the extent of metal interdiffusion. The one- and two-photon dynamics are measured using time-resolved absorption spectroscopy. We find that biexcitons undergo biexponential decays, with fast and slow decay times differing by about an order of magnitude. The relative magnitudes of the fast and slow components depend on the sharpness of the core-shell interface, with larger fast component amplitudes associated with a sharp core-shell interface. The slow component is assigned to Auger recombination of band edge carriers and the fast decay component to Auger recombination of holes that are trapped in defects produced by lattice strain. Annealing of these particles softens the core-shell interface and thereby reduces the amount of lattice strain and diminishes the magnitude of the fast decay component. The time constant of the slow biexciton Auger recombination component changes only slightly upon softening of the core-shell interface.
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Affiliation(s)
- Gary A Beane
- Chemistry and Chemical Biology, University of California Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - Ke Gong
- Chemistry and Chemical Biology, University of California Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - David F Kelley
- Chemistry and Chemical Biology, University of California Merced , 5200 North Lake Road, Merced, California 95343, United States
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