Optically detected magnetic resonance in CdSe/CdMnS nanoplatelets

Tolmachev, D. O.; Ivanov, V. Yu.; Yakovlev, D. R.; Shornikova, Elena V.; Witkowski, B.S.; Shendre, Sushant; Işık, Furkan; Delikani, Savas; Demir, Hilmi Volkan; Bayer, М.

doi:10.1039/d0nr05633b

Cited by 14 publications

(14 citation statements)

References 47 publications

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“…342 In Mn-doped core/shell NPLs the spin lifetime is found to be on the order of 100 μs at diluted doping levels. 574 Also, it has been demonstrated that dangling surface bonds in NPLs result in surface magnetism due to the localized spins of the dangling bond states behaving as magnetic ions. 379 This final illustration demonstrates the significance of surface control in NPLs for engineering their quantum properties, such as single-photon emission and spintronic.…”

Section: Other Applicationsmentioning

confidence: 99%

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

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The field of colloidal synthesis of semiconductors emerged 40 years ago and has reached a certain level of maturity thanks to the use of nanocrystals as phosphors in commercial displays. In particular, II−VI semiconductors based on cadmium, zinc, or mercury chalcogenides can now be synthesized with tailored shapes, composition by alloying, and even as nanocrystal heterostructures. Fifteen years ago, II−VI semiconductor nanoplatelets injected new ideas into this field. Indeed, despite the emergence of other promising semiconductors such as halide perovskites or 2D transition metal dichalcogenides, colloidal II−VI semiconductor nanoplatelets remain among the narrowest room-temperature emitters that can be synthesized over a wide spectral range, and they exhibit good material stability over time. Such nanoplatelets are scientifically and technologically interesting because they exhibit optical features and production advantages at the intersection of those expected from colloidal quantum dots and epitaxial quantum wells. In organic solvents, gram-scale syntheses can produce nanoparticles with the same thicknesses and optical properties without inhomogeneous broadening. In such nanoplatelets, quantum confinement is limited to one dimension, defined at the atomic scale, which allows them to be treated as quantum wells. In this review, we discuss the synthetic developments, spectroscopic properties, and applications of such nanoplatelets. Covering growth mechanisms, we explain how a thorough understanding of nanoplatelet growth has enabled the development of nanoplatelets and heterostructured nanoplatelets with multiple emission colors, spatially localized excitations, narrow emission, and high quantum yields over a wide spectral range. Moreover, nanoplatelets, with their large lateral extension and their thin short axis and low dielectric surroundings, can support one or several electron−hole pairs with large exciton binding energies. Thus, we also discuss how the relaxation processes and lifetime of the carriers and excitons are modified in nanoplatelets compared to both spherical quantum dots and epitaxial quantum wells. Finally, we explore how nanoplatelets, with their strong and narrow emission, can be considered as ideal candidates for pure-color light emitting diodes (LEDs), strong gain media for lasers, or for use in luminescent light concentrators.

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Section: Other Applicationsmentioning

confidence: 99%

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

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“…Two-dimensional colloidal nanoplatelets (NPLs) have a thickness of only several atomic layers but much larger in-plane extensions. , That is, the exciton confinement is extremely strong in the direction perpendicular to the NPL plane, while the in-plane motion is free. CdSe NPLs have remarkable optical properties with narrow emission lines, , low lasing threshold, strong optical gain, , and large multiphoton absorption cross section. , A wide variety of spin phenomena has recently been reported for NPLs. − The exciton with its large binding energy dominates the optical properties of CdSe NPLs. Therefore, comprehensive information on the exciton parameters is important.…”

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confidence: 99%

Exciton Binding Energy in CdSe Nanoplatelets Measured by One- and Two-Photon Absorption

et al. 2021

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Colloidal semiconductor nanoplatelets exhibit strong quantum confinement for electrons and holes as well as excitons in one dimension, while their in-plane motion is free. Because of the large dielectric contrast between the semiconductor and its ligand environment, the Coulomb interaction between electrons and holes is strongly enhanced. By means of one- and two-photon photoluminescence excitation spectroscopy, we measure the energies of the 1S and 1P exciton states in CdSe nanoplatelets with thicknesses varied from 3 up to 7 monolayers. By comparison with calculations, performed in the effective mass approximation with account of the dielectric enhancement, we evaluate exciton binding energies of 195–315 meV, which is about 20 times greater than that in bulk CdSe. Our calculations of the effective Coulomb potential for very thin nanoplatelets are close to the Rytova-Keldysh model, and the exciton binding energies are comparable with the values reported for monolayer-thick transition metal dichalcogenides.

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“…The Mn concentration in the shells is 1% in the sample #1 and 4% in the sample #2. The Mn concentrations were estimated by measuring the spin–lattice relaxation times (see refs and for the method description). In the sample #2, a small concentration of zinc (about 8%) was added to the (Cd,Zn,Mn)S shell.…”

Section: Resultsmentioning

confidence: 99%

High-Frequency EPR and ENDOR Spectroscopy of Mn²⁺ Ions in CdSe/CdMnS Nanoplatelets

et al. 2023

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Semiconductor colloidal nanoplatelets based of CdSe have excellent optical properties. Their magneto-optical and spin-dependent properties can be greatly modified by implementing magnetic Mn 2+ 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 Mn 2+ ions in core/shell CdSe/(Cd,Mn)S nanoplatelets. We observed two sets of resonances assigned to the Mn 2+ 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 Mn 2+ ions. The interaction between surface Mn 2+ ions and 1 H nuclei belonging to oleic acid ligands is measured by means of electron nuclear double resonance. This allowed us to estimate the distances between the Mn 2+ ions and 1 H nuclei, which equal to 0.31 ± 0.04, 0.44 ± 0.09, and more than 0.53 nm. This study shows that the Mn 2+ ions can serve as atomic-size probes for studying the ligand attachment to the nanoplatelet surface.

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Optically detected magnetic resonance in CdSe/CdMnS nanoplatelets

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...

Cited by 14 publications

References 47 publications

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Exciton Binding Energy in CdSe Nanoplatelets Measured by One- and Two-Photon Absorption

High-Frequency EPR and ENDOR Spectroscopy of Mn²⁺ Ions in CdSe/CdMnS Nanoplatelets

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Optically detected magnetic resonance in CdSe/CdMnS nanoplatelets

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...

Cited by 14 publications

References 47 publications

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Exciton Binding Energy in CdSe Nanoplatelets Measured by One- and Two-Photon Absorption

High-Frequency EPR and ENDOR Spectroscopy of Mn2+ Ions in CdSe/CdMnS Nanoplatelets

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High-Frequency EPR and ENDOR Spectroscopy of Mn²⁺ Ions in CdSe/CdMnS Nanoplatelets