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Climente JI, Movilla JL, Planelles J. Electronic Structure of Biexcitons in Metal Halide Perovskite Nanoplatelets. J Phys Chem Lett 2024:7379-7386. [PMID: 38995267 DOI: 10.1021/acs.jpclett.4c01719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
A theoretical description of biexcitons in metal halide perovskite nanoplatelets is presented. The description is based on a variational effective mass model, including polaronic effects by means of a Haken potential. The strong quantum and dielectric confinements are shown to squeeze the biexciton under the polaronic radius, which greatly enhances Coulomb attractions and (to a lesser extent) repulsions. This explains the need for effective dielectric constants approaching the high-frequency limit in previous simulations, and the binding energies exceeding 40 meV observed in single-monolayer nanoplatelets. Biexcitons are formed by a pair of weakly interacting excitons, with a roughly rectangular geometry. This translates into a constant ratio between biexciton and exciton binding energies (2D Haynes rule) well below the ideal value of ΔBX/ΔX = 0.228 proposed for squared biexcitons. The ratio is independent of the number of monolayers in the platelet, but it does depend on the lateral and dielectric confinement.
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Affiliation(s)
- Juan I Climente
- Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló de la Plana, Spain
| | - José L Movilla
- Dept. d'Educació i Didàctiques Específiques, Universitat Jaume I, 12080, Castelló, Spain
| | - Josep Planelles
- Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló de la Plana, Spain
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2
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Garoufalis CS, Hayrapetyan DB, Sarkisyan HA, Mantashyan PA, Zeng Z, Galanakis I, Bester G, Steenbock T, Baskoutas S. Optical gain and entanglement through dielectric confinement and electric field in InP quantum dots. NANOSCALE 2024; 16:8447-8454. [PMID: 38577736 DOI: 10.1039/d3nr06679g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Quantum dots are widely recognized for their advantageous light-emitting properties. Their excitonic fine structure along with the high quantum yields offers a wide range of possibilities for technological applications. However, especially for the case of colloidal QDs, there are still characteristics and properties which are not adequately controlled and downgrade their performance for applications which go far beyond the simple light emission. Such a challenging task is the ability to manipulate the energetic ordering of exciton and biexciton emission and subsequently control phenomena such as Auger recombination, optical gain and photon entanglement. In the present work we attempt to engineer this ordering for the case of InP QDs embedded in polymer matrix, by means of their size, the dielectric confinement and external electric fields. We employ well tested, state of the art theoretical methods, in order to explore the conditions under which the exciton-biexciton configuration creates the desired conditions either for optical gain or photon entanglement. Indeed, this appears to be feasible for QDs with small diameters (1 nm, 1.5 nm) embedded in a host material with high dielectric constant and additional external electric fields. These findings offer a new design principle which might be complementary to the well-established type II core-shell QDs approach for achieving electron-hole separation.
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Affiliation(s)
| | - David B Hayrapetyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, 123 Hovsep Emin Str., Yerevan 0051, Armenia
- Institute of Chemical Physics after A.B. Nalbandyan of NAS RA, 5/2 Paruyr Sevak St., Yerevan 0014, Armenia
| | - Hayk A Sarkisyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, 123 Hovsep Emin Str., Yerevan 0051, Armenia
| | - Paytsar A Mantashyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, 123 Hovsep Emin Str., Yerevan 0051, Armenia
- Institute of Chemical Physics after A.B. Nalbandyan of NAS RA, 5/2 Paruyr Sevak St., Yerevan 0014, Armenia
| | - Zaiping Zeng
- Key Laboratory for Special Functional Materials of Ministry of Education, Collaborative Innovation Center of Nano Functional Materials and Applications, and School of Materials Science and Engineering, Henan University, Kaifeng, Henan 475001, China
| | - Iosif Galanakis
- Materials Science Department, University of Patras, 26504 Patras, Greece.
| | - Gabriel Bester
- Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Torben Steenbock
- Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Sotirios Baskoutas
- Materials Science Department, University of Patras, 26504 Patras, Greece.
- Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
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Zhu C, Nguyen T, Boehme SC, Moskalenko A, Dirin DN, Bodnarchuk MI, Katan C, Even J, Rainò G, Kovalenko MV. Many-Body Correlations and Exciton Complexes in CsPbBr 3 Quantum Dots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208354. [PMID: 36537857 DOI: 10.1002/adma.202208354] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/25/2022] [Indexed: 06/17/2023]
Abstract
All-inorganic lead-halide perovskite (LHP) (CsPbX3 , X = Cl, Br, I) quantum dots (QDs) have emerged as a competitive platform for classical light-emitting devices (in the weak light-matter interaction regime, e.g., LEDs and laser), as well as for devices exploiting strong light-matter interaction at room temperature. Many-body interactions and quantum correlations among photogenerated exciton complexes play an essential role, for example, by determining the laser threshold, the overall brightness of LEDs, and the single-photon purity in quantum light sources. Here, by combining cryogenic single-QD photoluminescence spectroscopy with configuration-interaction (CI) calculations, the size-dependent trion and biexciton binding energies are addressed. Trion binding energies increase from 7 to 17 meV for QD sizes decreasing from 30 to 9 nm, while the biexciton binding energies increase from 15 to 30 meV, respectively. CI calculations quantitatively corroborate the experimental results and suggest that the effective dielectric constant for biexcitons slightly deviates from the one of the single excitons, potentially as a result of coupling to the lattice in the multiexciton regime. The findings here provide a deep insight into the multiexciton properties in all-inorganic LHP QDs, essential for classical and quantum optoelectronic devices.
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Affiliation(s)
- Chenglian Zhu
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
| | - Tan Nguyen
- Univ Rennes, ENSCR, CNRS, ISCR - UMR6226, Rennes, F-35000, France
| | - Simon C Boehme
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
| | - Anastasiia Moskalenko
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
| | - Dmitry N Dirin
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
| | - Maryna I Bodnarchuk
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
| | - Claudine Katan
- Univ Rennes, ENSCR, CNRS, ISCR - UMR6226, Rennes, F-35000, France
| | - Jacky Even
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON - UMR6082, Rennes, F-35000, France
| | - Gabriele Rainò
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
| | - Maksym V Kovalenko
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, CH-8600, Switzerland
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Martin PI, Panuganti S, Portner JC, Watkins NE, Kanatzidis MG, Talapin DV, Schaller RD. Excitonic Spin-Coherence Lifetimes in CdSe Nanoplatelets Increase Significantly with Core/Shell Morphology. NANO LETTERS 2023; 23:1467-1473. [PMID: 36753635 DOI: 10.1021/acs.nanolett.2c04845] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We report spin-polarized transient absorption for colloidal CdSe nanoplatelets as functions of thickness (2-6 monolayer thickness) and core/shell motif. Using electro-optical modulation of co- and cross-polarization pump-probe combinations, we sensitively observe spin-polarized transitions. Core-only nanoplatelets exhibit few-picosecond spin lifetimes that weakly increase with layer thickness. The spectral content of differenced spin-polarized signals indicate biexciton binding energies that decrease with increasing thickness and smaller values than previously reported. Shell growth of CdS with controlled thicknesses, which partially delocalize the electron from the hole, significantly increases the spin lifetime to ∼49 ps at room temperature. Implementation of ZnS shells, which do not alter delocalization but do alter surface termination, increased spin lifetimes up to ∼100 ps, bolstering the interpretation that surface termination heavily influences spin coherence, likely due to passivation of dangling bonds. Spin precession in magnetic fields both confirms long coherence lifetime at room temperature and yields the excitonic g factor.
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Affiliation(s)
- Phillip I Martin
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Shobhana Panuganti
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Joshua C Portner
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Nicolas E Watkins
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Mercouri G Kanatzidis
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Dmitri V Talapin
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Richard D Schaller
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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Diroll BT, Guzelturk B, Po H, Dabard C, Fu N, Makke L, Lhuillier E, Ithurria S. 2D II-VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration. Chem Rev 2023; 123:3543-3624. [PMID: 36724544 DOI: 10.1021/acs.chemrev.2c00436] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
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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Affiliation(s)
- Benjamin T Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Burak Guzelturk
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Hong Po
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Corentin Dabard
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Ningyuan Fu
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Lina Makke
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Emmanuel Lhuillier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, 75005 Paris, France
| | - Sandrine Ithurria
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
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6
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Rodà C, Geiregat P, Di Giacomo A, Moreels I, Hens Z. Area-Independence of the Biexciton Oscillator Strength in CdSe Colloidal Nanoplatelets. NANO LETTERS 2022; 22:9537-9543. [PMID: 36409988 DOI: 10.1021/acs.nanolett.2c03683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Colloidal CdSe nanoplatelets (NPLs) are unique systems to study two-dimensional excitons and excitonic complexes. However, while absorption and emission of photons through exciton formation and recombination have been extensively quantified, few studies have addressed the exciton-biexciton transition. Here, we use cross-polarized pump-probe spectroscopy to measure the absorption coefficient spectrum of this transition and determine the biexciton oscillator strength (fBX). We show that fBX is independent of the NPL area and that the concomitant biexciton area (SBX) agrees with predictions of a short-range interaction model. Moreover, we show that fBX is comparable to the oscillator strength of forming localized excitons at room temperature while being unaffected itself by center-of-mass localization. These results confirm the relevance of biexcitons for light-matter interaction in NPLs. Moreover, the quantification of the exciton-biexciton transition introduced here will enable researchers to rank 2D materials by the strength of this transition and to compare experimental results with theoretical predictions.
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Affiliation(s)
- Carmelita Rodà
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000Gent, Belgium
- NB-Photonics, Center for Nano- and Biophotonics, Ghent University, 9000Gent, Belgium
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000Gent, Belgium
- NB-Photonics, Center for Nano- and Biophotonics, Ghent University, 9000Gent, Belgium
| | - Alessio Di Giacomo
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000Gent, Belgium
- NB-Photonics, Center for Nano- and Biophotonics, Ghent University, 9000Gent, Belgium
| | - Iwan Moreels
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000Gent, Belgium
- NB-Photonics, Center for Nano- and Biophotonics, Ghent University, 9000Gent, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000Gent, Belgium
- NB-Photonics, Center for Nano- and Biophotonics, Ghent University, 9000Gent, Belgium
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