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Sukkabot W. Observation of spin-splitting energies on sp-d exchange interactions tailored in colloidal CdSe/CdMnS core/shell nanoplatelets: an atomistic tight-binding model. Phys Chem Chem Phys 2024; 26:11807-11814. [PMID: 38566596 DOI: 10.1039/d4cp00353e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Using the atomistic tight-binding model plus sp-d exchange term, the embedding of magnetic ions into CdSe/CdMnS core/shell nanoplatelets (NPLs) at different effective temperatures resulted in sp-d exchange interactions, which in turn cause modifications in electronic and magnetic characteristics. The influence of CdMnS monolayers on single-particle spectra, optical band gaps, wave function overlaps and exciton binding energies is more pronounced than that of the effective temperature. Due to the electron, hole and Zeeman splitting energies, with the growth of CdMnS shell monolayers, electron g-factor values are unchanged, but hole and exciton g-factor values are enhanced. Additionally, all g values decrease with increasing temperature, thus representing decreased magnetization of the paramagnetic system. By changing nanoplatelet architectures and temperatures, manipulation of s-d and p-d exchange interactions is accomplished. Overall, studied materials combine the merits of NPLs and magnetic ions, hence leading to alternate possibilities for active applications in spin-based devices.
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Affiliation(s)
- Worasak Sukkabot
- Department of Physics, Faculty of Science, Ubon Ratchathani University, 85 Sathollmark Rd. Warinchamrab, Ubon Ratchathani 34190, Thailand.
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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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Smirnova OO, Kalitukha IV, Rodina AV, Dimitriev GS, Sapega VF, Ken OS, Korenev VL, Kozyrev NV, Nekrasov SV, Kusrayev YG, Yakovlev DR, Dubertret B, Bayer M. Optical Alignment and Optical Orientation of Excitons in CdSe/CdS Colloidal Nanoplatelets. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2402. [PMID: 37686910 PMCID: PMC10489814 DOI: 10.3390/nano13172402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023]
Abstract
Optical alignment and optical orientation of excitons are studied experimentally on an ensemble of core/shell CdSe/CdS colloidal nanoplatelets. Linear and circular polarization of photoluminescence during resonant excitation of excitons is measured at cryogenic temperatures and with magnetic fields applied in the Faraday geometry. The developed theory addresses the optical alignment and optical orientation of excitons in colloidal nanocrystals, taking into account both bright and dark exciton states in the presence of strong electron-hole exchange interaction and the random in-plane orientation of nanoplatelets within the ensemble. Our theoretical analysis of the obtained experimental data allows us to evaluate the exciton fine structure parameters, the g-factors, and the spin lifetimes of the bright and dark excitons. The optical alignment effect enables the identification of the exciton and trion contributions to the emission spectrum, even in the absence of their clear separation in the spectra.
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Affiliation(s)
- Olga O. Smirnova
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Ina V. Kalitukha
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Anna V. Rodina
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | | | - Victor F. Sapega
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Olga S. Ken
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | | | - Nikolai V. Kozyrev
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Sergey V. Nekrasov
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Yuri G. Kusrayev
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Dmitri R. Yakovlev
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Benoit Dubertret
- Laboratoire de Physique et d’Étude des Matériaux, ESPCI, CNRS, 75231 Paris, France
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
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4
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Babunts RA, Uspenskaya YA, Romanov NG, Orlinskii SB, Mamin GV, Shornikova EV, Yakovlev DR, Bayer M, Isik F, Shendre S, Delikanli S, Demir HV, Baranov PG. High-Frequency EPR and ENDOR Spectroscopy of Mn 2+ Ions in CdSe/CdMnS Nanoplatelets. ACS NANO 2023; 17:4474-4482. [PMID: 36802485 DOI: 10.1021/acsnano.2c10123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Semiconductor colloidal nanoplatelets based of CdSe have excellent optical properties. Their magneto-optical and spin-dependent properties can be greatly modified by implementing magnetic Mn2+ ions, using concepts well established for diluted magnetic semiconductors. A variety of magnetic resonance techniques based on high-frequency (94 GHz) electron paramagnetic resonance in continuous wave and pulsed mode were used to get detailed information on the spin structure and spin dynamics of Mn2+ ions in core/shell CdSe/(Cd,Mn)S nanoplatelets. We observed two sets of resonances assigned to the Mn2+ ions inside the shell and at the nanoplatelet surface. The surface Mn demonstrates a considerably longer spin dynamics than the inner Mn due to lower amount of surrounding Mn2+ ions. The interaction between surface Mn2+ ions and 1H nuclei belonging to oleic acid ligands is measured by means of electron nuclear double resonance. This allowed us to estimate the distances between the Mn2+ ions and 1H nuclei, which equal to 0.31 ± 0.04, 0.44 ± 0.09, and more than 0.53 nm. This study shows that the Mn2+ ions can serve as atomic-size probes for studying the ligand attachment to the nanoplatelet surface.
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Affiliation(s)
- Roman A Babunts
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Yulia A Uspenskaya
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Nikolai G Romanov
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | | | - Georgy V Mamin
- Kazan Federal University, Institute of Physics, 420008 Kazan, Russia
| | - Elena V Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Dmitri R Yakovlev
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Furkan Isik
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Sushant Shendre
- Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
| | - Savas Delikanli
- Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Hilmi Volkan Demir
- Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Pavel G Baranov
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
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Ashraf GA, Rasool RT, Pasha M, Rasool RU, Chen J, Khosa AA, Mahmood S, Hassan M, Guo H. Peroxymonosulfate-based photocatalytic oxidation of tetracycline by Fe 2(MoO 4) 3/Cd 0.5Ni 0.5S heterostructure; DFT simulation. CHEMOSPHERE 2022; 309:136423. [PMID: 36210575 DOI: 10.1016/j.chemosphere.2022.136423] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
The current research is meant to develop novel semiconductor photocatalysts, for the decomposition of tetracycline (TC) as a model organic contaminant in the aquatic environment. The fabrication of Fe2(MoO4)3/Cd0.5Ni0.5S (FMO/CNS) composite has proven to be an effective method for improving the sustainability and photocatalytic activity of Cd0.5Ni0.5S (CNS). Under visible light irradiation, FMO/CNS nanocomposite demonstrated significant PMS activation which led to 1.36 and 1.81 times TC removal efficiency as compared to immaculate Fe2(MoO4)3(FMO) and CNS. FMO/CNS composite potentially promotes the segregation of electron-hole pairs (e--h+) and exemplifies amazing photocatalytic performance for TC degradation. Its significant photocatalytic activity is due to its unique structure, which includes tiny pores on the surface that confine the PMS molecule to the interface. The FMO/CNS composite has significantly greater piezocatalytic activity than pure FMO and CNS, demonstrating the synergistic effect of FMO and CNS. In the degradation of TC, holes and key reactive radicals (•O2-/•OH/SO4-•) played a major role. Computational studies (DFT) estimates, including the determination of intermediates, confirmed that the hydroxyl addition and C-N cleavage pathways were responsible for TC degradation. As a result, this work delivers a new approach to developing novel photocatalysts with high photocatalytic activity for the abatement of organic contaminants in water.
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Affiliation(s)
- Ghulam Abbas Ashraf
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Raqiqa Tur Rasool
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China.
| | - Mohsin Pasha
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Rafiqat Ul Rasool
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China
| | - Junyu Chen
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Azhar Abbas Khosa
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu, China; Mechanical Engineering Department, NFC Institute of Engineering and Technology Multan, Pakistan
| | - Sajid Mahmood
- Department of Chemistry, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Muhammad Hassan
- Faculty of Geoscience and Environmental Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 611756, China.
| | - Hai Guo
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China.
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6
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Ultrafast Quenching of Excitons in the Zn xCd 1-xS/ZnS Quantum Dots Doped with Mn 2+ through Charge Transfer Intermediates Results in Manganese Luminescence. NANOMATERIALS 2021; 11:nano11113007. [PMID: 34835771 PMCID: PMC8618633 DOI: 10.3390/nano11113007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/27/2021] [Accepted: 11/03/2021] [Indexed: 11/17/2022]
Abstract
For the first time, a specific time-delayed peak was registered in the femtosecond transient absorption (TA) spectra of ZnxCd1−xS/ZnS (x~0.5) alloy quantum dots (QDs) doped with Mn2+, which was interpreted as the electrochromic Stark shift of the band-edge exciton. The time-delayed rise and decay kinetics of the Stark peak in the manganese-doped QDs significantly distinguish it from the kinetics of the Stark peak caused by exciton–exciton interaction in the undoped QDs. The Stark shift in the Mn2+-doped QDs developed at a 1 ps time delay in contrast to the instantaneous appearance of the Stark shift in the undoped QDs. Simultaneously with the development of the Stark peak in the Mn2+-doped QDs, stimulated emission corresponding to 4T1-6A1 Mn2+ transition was detected in the subpicosecond time domain. The time-delayed Stark peak in the Mn2+-doped QDs, associated with the development of an electric field in QDs, indicates the appearance of charge transfer intermediates in the process of exciton quenching by manganese ions, leading to the ultrafast Mn2+ excitation. The usually considered mechanism of the nonradiative energy transfer from an exciton to Mn2+ does not imply the development of an electric field in a QD. Femtosecond TA data were analyzed using a combination of empirical and computational methods. A kinetic scheme of charge transfer processes is proposed to explain the excitation of Mn2+. The kinetic scheme includes the reduction of Mn2+ by a 1Se electron and the subsequent oxidation of Mn1+ with a hole, leading to the formation of an excited state of manganese.
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7
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Lorenz S, Bieniek J, Erickson CS, Gamelin DR, Fainblat R, Bacher G. Orientation of Individual Anisotropic Nanocrystals Identified by Polarization Fingerprint. ACS NANO 2021; 15:13579-13590. [PMID: 34339182 DOI: 10.1021/acsnano.1c04451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The polarization of photoluminescence emitted from anisotropic nanocrystals directly reflects the symmetry of the eigenstates involved in the recombination process and can thus be considered as a characteristic feature of a nanocrystal. We performed polarization resolved magneto-photoluminescence spectroscopy on single colloidal Mn2+:CdSe/CdS core-shell quantum dots of wurtzite crystal symmetry. At zero magnetic field, a distinct linear polarization pattern is observed, while applying a magnetic field enforces circularly polarized emission with a characteristic saturation value below 100%. These polarization features are shown to act as a specific fingerprint of each individual nanocrystal. A model considering the orientation of the crystal c⃗ axis with respect to the optical axis and the magnetic field and taking into account the impact of magnetic doping is introduced and quantitatively explains our findings. We demonstrate that a careful analysis of the polarization state of single nanocrystal emission using the full set of Stokes parameters allows for identification of the complete three-dimensional orientation of the crystal anisotropy axis of an individual nanoobject in lab coordinates.
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Affiliation(s)
- Severin Lorenz
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
| | - Jan Bieniek
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
| | - Christian S Erickson
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Rachel Fainblat
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
| | - Gerd Bacher
- Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstr. 81, Duisburg 47057 Germany
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8
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Najafi A, Sharma M, Delikanli S, Bhattacharya A, Murphy JR, Pientka J, Sharma A, Quinn AP, Erdem O, Kattel S, Kelestemur Y, Kovalenko MV, Rice WD, Demir HV, Petrou A. Light-Induced Paramagnetism in Colloidal Ag +-Doped CdSe Nanoplatelets. J Phys Chem Lett 2021; 12:2892-2899. [PMID: 33724845 DOI: 10.1021/acs.jpclett.1c00398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We describe a study of the magneto-optical properties of Ag+-doped CdSe colloidal nanoplatelets (NPLs) that were grown using a novel doping technique. In this work, we used magnetic circularly polarized luminescence and magnetic circular dichroism spectroscopy to study light-induced magnetism for the first time in 2D solution-processed structures doped with nominally nonmagnetic Ag+ impurities. The excitonic circular polarization (PX) and the exciton Zeeman splitting (ΔEZ) were recorded as a function of the magnetic field (B) and temperature (T). Both ΔEZ and PX have a Brillouin-function-like dependence on B and T, verifying the presence of paramagnetism in Ag+-doped CdSe NPLs. The observed light-induced magnetism is attributed to the transformation of nonmagnetic Ag+ ions into Ag2+, which have a nonzero magnetic moment. This work points to the possibility of incorporating these nanoplatelets into spintronic devices, in which light can be used to control the spin injection.
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Affiliation(s)
- Arman Najafi
- Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, United States
| | - Manoj Sharma
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Savas Delikanli
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Arinjoy Bhattacharya
- Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, United States
| | - Joseph R Murphy
- Department of Chemistry and Physics, Southeast Missouri State University, Cape Girardeau, Missouri 63701, United States
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - James Pientka
- Department of Physics, St. Bonaventure University, St. Bonaventure, New York 14778, United States
| | - Ashma Sharma
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798
| | - Alexander P Quinn
- Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, United States
| | - Onur Erdem
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Subash Kattel
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Yusuf Kelestemur
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
- Department of Metallurgical and Materials Engineering, Atilim University, Ankara 06830, Turkey
| | - Maksym V Kovalenko
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - William D Rice
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Hilmi Volkan Demir
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Athos Petrou
- Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, United States
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9
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Tolmachev DO, Ivanov VY, Yakovlev DR, Shornikova EV, Witkowski B, Shendre S, Isik F, Delikani S, Demir HV, Bayer M. Optically detected magnetic resonance in CdSe/CdMnS nanoplatelets. NANOSCALE 2020; 12:21932-21939. [PMID: 33112343 DOI: 10.1039/d0nr05633b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Core/shell CdSe/(Cd,Mn)S colloidal nanoplatelets containing magnetic Mn2+ ions are investigated by the optically detected magnetic resonance technique, combining 60 GHz microwave excitation and photoluminescence detection. Resonant heating of the Mn spin system is observed. We identify two mechanisms of optical detection, via variation of either the photoluminescence polarization or its intensity in an external magnetic field. The spin-lattice relaxation dynamics of the Mn spin system is measured and used for evaluation of the Mn concentration. In CdSe/(Cd,Zn,Mn)S nanoplatelets the addition of Zn in the shells significantly broadens the magnetic resonance, evidencing local strain.
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Affiliation(s)
- Danil O Tolmachev
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany.
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10
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Dehnel J, Barak Y, Meir I, Budniak AK, Nagvenkar AP, Gamelin DR, Lifshitz E. Insight into the Spin Properties in Undoped and Mn-Doped CdSe/CdS-Seeded Nanorods by Optically Detected Magnetic Resonance. ACS NANO 2020; 14:13478-13490. [PMID: 32935976 DOI: 10.1021/acsnano.0c05454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Controlling the spin degrees of freedom of photogenerated species in semiconductor nanostructures via magnetic doping is an emerging scientific field that may play an important role in the development of new spin-based technologies. The current work explores spin properties in colloidal CdSe/CdS:Mn seeded-nanorod structures doped with a dilute concentration of Mn2+ ions across the rods. The spin properties were determined using continuous-wave optically detected magnetic resonance (ODMR) spectroscopy recorded under variable microwave chopping frequencies. These experiments enabled the deconvolution of a few different radiative recombination processes: band-to-band, trap-to-band, and trap-to-trap emission. The results uncovered the major role of carrier trapping on the spin properties of elongated structures. The magnetic parameters, determined through spin-Hamiltonian simulation of the steady-state ODMR spectra, reflect anisotropy associated with carrier trapping at the seed/rod interface. These observations unveiled changes in the carriers' g-factors and spin-exchange coupling constants as well as extension of radiative and spin-lattice relaxation times due to magnetic coupling between interface carriers and neighboring Mn2+ ions. Overall, this work highlights that the spin degrees of freedom in seeded nanorods are governed by interfacial trapping and can be further manipulated by magnetic doping. These results provide insights into anisotropic nanostructure spin properties relevant to future spin-based technologies.
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Affiliation(s)
- Joanna Dehnel
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Itay Meir
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Adam K Budniak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Anjani P Nagvenkar
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Daniel R Gamelin
- Department of Chemistry and the Molecular Engineering Materials Center, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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