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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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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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Rajan D, Muraleedharan A, Variyar A, Verma P, Pinhero F, Lakshmanna YA, Sabari Sankar T, Thomas KG. Single- and two-photon-induced Förster resonance energy transfer in InP-mCherry bioconjugates. J Chem Phys 2024; 160:044712. [PMID: 38294316 DOI: 10.1063/5.0186483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/05/2024] [Indexed: 02/01/2024] Open
Abstract
Indium phosphide (InP) quantum dots (QDs) have recently garnered considerable interest in the design of bioprobes due to their non-toxic nature and excellent optical properties. Several attempts for the conjunction of InP QDs with various entities such as organic dyes and dye-labeled proteins have been reported, while that with fluorescent proteins remains largely uncharted. This study reports the development of a Förster resonance energy transfer pair comprising glutathione-capped InP/GaP/ZnS QDs [InP(G)] and the fluorescent protein mCherry. Glutathione on InP(G) undergoes effective bioconjugation with mCherry consisting of a hexahistidine tag, and the nonradiative energy transfer is investigated using steady-state and time-resolved measurements. Selective one-photon excitation of InP(G) in the presence of mCherry shows a decay of the emission of the QDs and a concomitant growth of acceptor emission. Time-resolved investigations prove the nonradiative transfer of energy between InP(G) and mCherry. Furthermore, the scope of two-photon-induced energy transfer between InP(G) and mCherry is investigated by exciting the donor in the optical transparency range. The two-photon absorption is confirmed by the quadratic relationship between the emission intensity and the excitation power. In general, near-infrared excitation provides a path for effective light penetration into the tissues and reduces the photodamage of the sample. The two-photon-induced energy transfer in such assemblies could set the stage for a wide range of biological and optoelectronic applications in the foreseeable future.
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Affiliation(s)
- Devika Rajan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Ananthu Muraleedharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Anjali Variyar
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Preetika Verma
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Faina Pinhero
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - Yapamanu Adithya Lakshmanna
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - T Sabari Sankar
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
| | - K George Thomas
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India
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