1
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Kelley DF. Angular Momentum Fine Structure in InP/ZnSe Quantum Dots. J Phys Chem Lett 2024; 15:6279-6285. [PMID: 38848253 DOI: 10.1021/acs.jpclett.4c01202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
There is a large experimental and theoretical literature on the angular momentum fine structure of the lowest energy exciton in InP-based quantum dots. This literature is highly contradictory, and no clear picture of the fine structure accounting for all these results is available. This paper presents a quantitative analysis of recently published luminescence anisotropy results and presents an analysis of the different proposed fine structure models that compares radiative lifetimes calculated from those models with experimental values. These analyses show that the lowest energy (dark) state is the mj = ±2 state and the lowest energy bright state is a vibronically allowed phonon level. The splittings between the ±2/±1L states and the ±1U/0U states are the same, about 28 meV. We also find that the manifold of J = 1 states is about 60 meV above the manifold of J = 2 states.
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Affiliation(s)
- David F Kelley
- Department of Chemistry and Biochemistry, University of California Merced, 5200 North Lake Road, Merced, California 95343, United States
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2
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Tolmachev DO, Fernée MJ, Shornikova EV, Siverin NV, Yakovlev DR, Van Avermaet H, Hens Z, Bayer M. Positive Trions in InP/ZnSe/ZnS Colloidal Nanocrystals. ACS NANO 2024; 18:9378-9388. [PMID: 38498768 DOI: 10.1021/acsnano.3c09971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
InP-based colloidal nanocrystals are being developed as an alternative to cadmium-based materials. However, their optical properties have not been widely studied. In this paper, the fundamental magneto-optical properties of InP/ZnSe/ZnS nanocrystals are investigated at cryogenic temperatures. Ensemble measurements using two-photon excitation spectroscopy revealed the band-edge hole state to have 1Sh symmetry, resolving some controversy on this issue. Single nanocrystal microphotoluminescence measurements provided increased spectral resolution that facilitated direct detection of the lowest energy confined acoustic phonon mode at 0.9 meV, which is several times smaller than the previously reported values for similar nanocrystals. Zeeman splitting of narrow spectral lines in a magnetic field indicated a bright trion emission. A simple trion model was used to identify a positive trion charge. Furthermore, the Zeeman split spectra allowed the direct measurement of both the electron and hole g-factors, which match existing theoretical predictions.
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Affiliation(s)
- Danil O Tolmachev
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Mark J Fernée
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Elena V Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Nikita V Siverin
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Dmitri R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Hannes Van Avermaet
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
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3
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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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4
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Almeida G, van der Poll L, Evers WH, Szoboszlai E, Vonk SJW, Rabouw FT, Houtepen AJ. Size-Dependent Optical Properties of InP Colloidal Quantum Dots. NANO LETTERS 2023; 23:8697-8703. [PMID: 37672486 PMCID: PMC10540257 DOI: 10.1021/acs.nanolett.3c02630] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/25/2023] [Indexed: 09/08/2023]
Abstract
Indium phosphide colloidal quantum dots (CQDs) are the main alternative for toxic and restricted Cd based CQDs for lighting and display applications. Here we systematically report on the size-dependent optical absorption, ensemble, and single particle photoluminescence (PL) and biexciton lifetimes of core-only InP CQDs. This systematic study is enabled by improvements in the synthesis of InP CQDs to yield a broad size series of monodisperse core-only InP CQDs with narrow absorption and PL line width and significant PL quantum yield.
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Affiliation(s)
- Guilherme Almeida
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The
Netherlands
| | - Lara van der Poll
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The
Netherlands
| | - Wiel H. Evers
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The
Netherlands
| | - Emma Szoboszlai
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The
Netherlands
| | - Sander J. W. Vonk
- Debye
Institute for Nanomaterials Science, Utrecht
University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Freddy T. Rabouw
- Debye
Institute for Nanomaterials Science, Utrecht
University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Arjan J. Houtepen
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The
Netherlands
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5
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Chandrasekaran V, Scarpelli L, Masia F, Borri P, Langbein W, Hens Z. Exciton Dephasing by Phonon-Induced Scattering between Bright Exciton States in InP/ZnSe Colloidal Quantum Dots. ACS NANO 2023. [PMID: 37326256 DOI: 10.1021/acsnano.2c12182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Decoherence or dephasing of the exciton is a central characteristic of a quantum dot (QD) that determines the minimum width of the exciton emission line and the purity of indistinguishable photon emission during exciton recombination. Here, we analyze exciton dephasing in colloidal InP/ZnSe QDs using transient four-wave mixing spectroscopy. We obtain a dephasing time of 23 ps at a temperature of 5 K, which agrees with the smallest line width of 50 μeV we measure for the exciton emission of single InP/ZnSe QDs at 5 K. By determining the dephasing time as a function of temperature, we find that exciton decoherence can be described as a phonon-induced, thermally activated process. The deduced activation energy of 0.32 meV corresponds to the small splitting within the nearly isotropic bright exciton triplet of InP/ZnSe QDs, suggesting that the dephasing is dominated by phonon-induced scattering within the bright exciton triplet.
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Affiliation(s)
- Vigneshwaran Chandrasekaran
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Gent, Belgium
- Center for Nano and Biophotonics, Ghent University, 9000 Gent, Belgium
| | - Lorenzo Scarpelli
- Cardiff University School of Physics and Astronomy, The Parade, Cardiff CF24 3AA, United Kingdom
| | - Francesco Masia
- Cardiff University School of Physics and Astronomy, The Parade, Cardiff CF24 3AA, United Kingdom
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, United Kingdom
| | - Paola Borri
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, United Kingdom
| | - Wolfgang Langbein
- Cardiff University School of Physics and Astronomy, The Parade, Cardiff CF24 3AA, United Kingdom
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Gent, Belgium
- Center for Nano and Biophotonics, Ghent University, 9000 Gent, Belgium
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6
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Kim Y, Hu Z, Avdeev ID, Singh A, Singh A, Chandrasekaran V, Nestoklon MO, Goupalov SV, Hollingsworth JA, Htoon H. Interplay of Bright Triplet and Dark Excitons Revealed by Magneto-Photoluminescence of Individual PbS/CdS Quantum Dots. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006977. [PMID: 33690965 DOI: 10.1002/smll.202006977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/22/2021] [Indexed: 06/12/2023]
Abstract
A low-temperature polarization-resolved magneto-photoluminescence experiment is performed on individual PbS/CdS core/shell quantum dots (QDs). The experiment enables a direct measurement of the exciton Landé g factor and the anisotropic zero-field splitting of the lowest emissive bright exciton triplet in PbS/CdS QDs. While anisotropic splittings of individual QDs distribute randomly in 104-325 μeV range, the exciton Landé g factors increase from 0.95 to 2.70 as the emission energy of the QD increases from 1.0 to 1.2 eV. The tight-binding calculations allow to rationalize these trends as a direct consequence of reducing a cubic symmetry of QD via addition/removal of a few (<70) atoms from the surfaces of the PbS core. Furthermore, it is observed that while right (σ + ) and left (σ - ) circularly polarized photoluminescence (PL) peaks split linearly with magnetic field as expected for Zeeman effect, the energy splitting between X and Y linearly polarized PL peaks remains nearly unchanged. The theoretical study reveals rich and complex magnetic field-induced interplay of bright triplet and dark exciton states explaining this puzzling behavior. These findings fill the missing gaps in the understanding of lead salt QDs and provide foundation for development of classical and quantum light sources operating at telecommunication wavelengths.
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Affiliation(s)
- Younghee Kim
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Zhongjian Hu
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | | | - Ajay Singh
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Amita Singh
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Vigneshwaran Chandrasekaran
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | | | - Serguei V Goupalov
- Ioffe Institute, St. Petersburg, 194021, Russia
- Department of Physics, Jackson State University, Jackson, MS 39217, USA
| | - Jennifer A Hollingsworth
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Han Htoon
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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7
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Qiang G, Golovatenko AA, Shornikova EV, Yakovlev DR, Rodina AV, Zhukov EA, Kalitukha IV, Sapega VF, Kaibyshev VK, Prosnikov MA, Christianen PCM, Onushchenko AA, Bayer M. Polarized emission of CdSe nanocrystals in magnetic field: the role of phonon-assisted recombination of the dark exciton. NANOSCALE 2021; 13:790-800. [PMID: 33351019 DOI: 10.1039/d0nr07117j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The recombination dynamics and spin polarization of excitons in CdSe nanocrystals synthesized in a glass matrix are investigated using polarized photoluminescence in high magnetic fields up to 30 Tesla. The dynamics are accelerated by increasing temperature and magnetic field, confirming the dark exciton nature of low-temperature photoluminescence (PL). The circularly polarized PL in magnetic fields reveals several unusual appearances: (i) a spectral dependence of the polarization degree, (ii) its low saturation value, and (iii) a stronger intensity of the Zeeman component which is higher in energy. The latter feature is the most surprising being in contradiction with the thermal population of the exciton spin sublevels. The same contradiction was previously observed in the ensemble of wet-chemically synthesized CdSe nanocrystals but was not understood. We present a theory which explains all the observed features and shows that the inverted ordering of the circularly polarized PL maxima from the ensemble of nanocrystals is a result of competition between the zero phonon (ZPL) and one optical phonon-assisted (1PL) emission of the dark excitons. The essential aspects of the theoretical model are different polarization properties of the dark exciton emission via ZPL and 1PL recombination channels and the inhomogeneous broadening of the PL spectrum from the ensemble of nanocrystals exceeding the optical phonon energy.
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Affiliation(s)
- Gang Qiang
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany.
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8
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Chen B, Li D, Wang F. InP Quantum Dots: Synthesis and Lighting Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002454. [PMID: 32613755 DOI: 10.1002/smll.202002454] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/30/2020] [Indexed: 05/24/2023]
Abstract
InP quantum dots (QDs) are typical III-V group semiconductor nanocrystals that feature large excitonic Bohr radius and high carrier mobility. The merits of InP QDs include large absorption coefficient, broad color tunability, and low toxicity, which render them promising alternatives to classic Cd/Pb-based QDs for applications in practical settings. Over the past two decades, the advances in wet-chemistry methods have enabled the synthesis of small-sized colloidal InP QDs with the assistance of organic ligands. By proper selection of synthetic protocols and precursor materials coupled with surface passivation, the QYs of InP QDs are pushed to near unity with modest color purity. The state-of-the-art InP QDs with appealing optical and electronic properties have excelled in many applications with the potential for commercialization. This work focuses on the recent development of wet-chemistry protocols and various precursor materials for the synthesis and surface modification of InP QDs. Current methods for constructing light-emitting diodes using novel InP-based QDs are also summarized.
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Affiliation(s)
- 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
| | - Dongyu Li
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- Key Laboratory of Environmentally Friendly Functional Materials and Devices, Lingnan Normal University, Zhanjiang, 524048, 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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9
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Zhang H, Ma X, Lin Q, Zeng Z, Wang H, Li LS, Shen H, Jia Y, Du Z. High-Brightness Blue InP Quantum Dot-Based Electroluminescent Devices: The Role of Shell Thickness. J Phys Chem Lett 2020; 11:960-967. [PMID: 31957438 DOI: 10.1021/acs.jpclett.9b03567] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
InP quantum dots (QDs) are considered as one of the most promising candidates of Cd- or Pb-based QDs in the applications of display and lighting. However, the performances of blue InP QDs and the corresponding light emitting devices (LEDs) are far inferior to those of their red and green counterparts, which strongly limits the development of InP QD based LEDs (QLEDs) technology. Here, high quantum yield (∼81%) and large size (∼7.0 ± 0.9 nm) InP/GaP/ZnS//ZnS QDs with a thick shell have been successfully synthesized by a shell engineering approach, and the corresponding QLEDs exhibit a record brightness and external quantum efficiency of 3120 cd·m-2 and 1.01%, respectively. Large-scale density functional theory calculations on thousands-of-atoms QDs indicate that thicker-shell ones favor a more balanced carrier injection in the QD film and simultaneously suppress the FRET between closely packed QDs, which collectively contribute to the improved blue device performances.
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Affiliation(s)
- Han Zhang
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Xiaoyu Ma
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Qingli Lin
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Zaiping Zeng
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Hongzhe Wang
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Lin Song Li
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Huaibin Shen
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
| | - Yu Jia
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
- International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering , Zhengzhou University , Zhengzhou 450001 , Henan , China
| | - Zuliang Du
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications , Henan University , Kaifeng 475004 , Henan , China
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10
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Huang F, Bi C, Guo R, Zheng C, Ning J, Tian J. Synthesis of Colloidal Blue-Emitting InP/ZnS Core/Shell Quantum Dots with the Assistance of Copper Cations. J Phys Chem Lett 2019; 10:6720-6726. [PMID: 31549508 DOI: 10.1021/acs.jpclett.9b02386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Colloidal InP quantum dots (QDs) have been considered as one of the most promising candidates for display and biolabeling applications because they are intrinsically toxicity-free and exhibit high photoluminescence. On account of the uncontrollable nucleation and growth during the synthesis of InP, obtaining high-quality blue-emitting InP QDs with uniform size distribution remains a challenge. Herein, we employ a novel synthetic approach for producing blue-emitting InP/ZnS core/shell QDs with the assistance of copper cations. The studies reveal that the copper ions could combine with phosphorus precursor to form hexagonal Cu3-xP nanocrystals, which competed with the nucleation process of InP QDs, resulting in the smaller sized InP QDs with blue photoluminescence emission. After the passivation of InP QDs with the ZnS shell, the synthesized InP/ZnS core/shell QDs present bright blue emission (∼425 nm) with a photoluminescence quantum yield of ∼25%, which is the shortest wavelength emission for InP QDs to date. This research provides a new way to synthesize ultrasmall semiconductor nanocrystals.
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Affiliation(s)
- Fan Huang
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Chenghao Bi
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Ruiqi Guo
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Chao Zheng
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Jiajia Ning
- Department of Materials Science and Engineering & Centre for Functional Photonics (CFP) , City University of Hong Kong , Kowloon , Hong Kong SAR , China
| | - Jianjun Tian
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
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11
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Brodu A, Tessier MD, Canneson D, Dupont D, Ballottin MV, Christianen PCM, de Mello Donega C, Hens Z, Yakovlev DR, Bayer M, Vanmaekelbergh D, Biadala L. Hyperfine Interactions and Slow Spin Dynamics in Quasi-isotropic InP-based Core/Shell Colloidal Nanocrystals. ACS NANO 2019; 13:10201-10209. [PMID: 31464420 DOI: 10.1021/acsnano.9b03384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Colloidal InP core nanocrystals are taking over CdSe-based nanocrystals, notably in optoelectronic applications. Despite their use in commercial devices, such as display screens, the optical properties of InP nanocrystals and especially their relation to the exciton fine structures remain poorly understood. In this work, we show that the ensemble magneto-optical properties of InP-based core/shell nanocrystals investigated in strong magnetic fields up to 30 T are strikingly different from other colloidal nanostructures. Notably, the mixing of the lowest spin-forbidden dark exciton state with the nearest spin-allowed bright state does not occur up to the highest magnetic fields applied. This lack of mixing in an ensemble of nanocrystals suggests an anisotropy tolerance of InP nanocrystals. This striking property allowed us to unveil the slow spin dynamics between Zeeman sublevels (up to 400 ns at 15 T). Furthermore, we show that the unexpected magnetic-field-induced lengthening of the dark exciton lifetime results from the hyperfine interaction between the spin of the electron in the dark exciton with the nuclear magnetic moments. Our results demonstrate the richness of the spin physics in InP quantum dots and stress the large potential of InP nanostructures for spin-based applications.
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Affiliation(s)
- Annalisa Brodu
- Debye Institute for Nanomaterials Science , Utrecht University , 3584 CC Utrecht , The Netherlands
| | - Mickael D Tessier
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
| | - Damien Canneson
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
| | - Dorian Dupont
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
| | - Mariana V Ballottin
- High Field Magnet Laboratory, HFML-EMFL , Radboud University , 6525 ED Nijmegen , The Netherlands
| | - Peter C M Christianen
- High Field Magnet Laboratory, HFML-EMFL , Radboud University , 6525 ED Nijmegen , The Netherlands
| | - Celso de Mello Donega
- Debye Institute for Nanomaterials Science , Utrecht University , 3584 CC Utrecht , The Netherlands
| | - Zeger Hens
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
| | - Dmitri R Yakovlev
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
- Ioffe Institute , Russian Academy of Sciences , 194021 St. Petersburg , Russia
| | - Manfred Bayer
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
- Ioffe Institute , Russian Academy of Sciences , 194021 St. Petersburg , Russia
| | - Daniel Vanmaekelbergh
- Debye Institute for Nanomaterials Science , Utrecht University , 3584 CC Utrecht , The Netherlands
| | - Louis Biadala
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
- Institut d'Électronique, de Microélectronique et de Nanotechnologie , UMR CNRS 8520 , 59652 Villeneuve d'Ascq , France
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