1
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Oggianu M, Mameli V, Hernández-Rodríguez MA, Monni N, Souto M, Brites CD, Cannas C, Manna F, Quochi F, Cadoni E, Masciocchi N, Carneiro Neto AN, Carlos LD, Mercuri ML. Insights into Nd III to Yb III Energy Transfer and Its Implications in Luminescence Thermometry. Chem Mater 2024; 36:3452-3463. [PMID: 38617804 PMCID: PMC11008107 DOI: 10.1021/acs.chemmater.4c00362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 04/16/2024]
Abstract
This work challenges the conventional approach of using NdIII 4F3/2 lifetime changes for evaluating the experimental NdIII → YbIII energy transfer rate and efficiency. Using near-infrared (NIR) emitting Nd:Yb mixed-metal coordination polymers (CPs), synthesized via solvent-free thermal grinding, we demonstrate that the NdIII [2H11/2 → 4I15/2] → YbIII [2F7/2 → 2F5/2] pathway, previously overlooked, dominates energy transfer due to superior energy resonance and J-level selection rule compatibility. This finding upends the conventional focus on the NdIII [4F3/2 → 4I11/2] → YbIII [2F7/2 → 2F5/2] transition pathway. We characterized Nd0.890Yb0.110(BTC)(H2O)6 as a promising cryogenic NIR thermometry system and employed our novel energy transfer understanding to perform simulations, yielding theoretical thermometric parameters and sensitivities for diverse Nd:Yb ratios. Strikingly, experimental thermometric data closely matched the theoretical predictions, validating our revised model. This novel perspective on NdIII → YbIII energy transfer holds general applicability for the NdIII/YbIII pair, unveiling an important spectroscopic feature with broad implications for energy transfer-driven materials design.
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Affiliation(s)
- Mariangela Oggianu
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
- INSTM, Via Giuseppe Giusti, 9, Firenze 50121, Italy
| | - Valentina Mameli
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
- INSTM, Via Giuseppe Giusti, 9, Firenze 50121, Italy
| | - Miguel A. Hernández-Rodríguez
- Phantom-g,
Department of Physics, CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro 3810-193, Portugal
| | - Noemi Monni
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
- INSTM, Via Giuseppe Giusti, 9, Firenze 50121, Italy
| | - Manuel Souto
- Department
of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro 3810-193, Portugal
| | - Carlos D.S. Brites
- Phantom-g,
Department of Physics, CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro 3810-193, Portugal
| | - Carla Cannas
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
- INSTM, Via Giuseppe Giusti, 9, Firenze 50121, Italy
| | - Fabio Manna
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
| | - Francesco Quochi
- INSTM, Via Giuseppe Giusti, 9, Firenze 50121, Italy
- Dipartimento
di Fisica, Università degli Studi
di Cagliari, Complesso Universitario di Monserrato, Monserrato I-09042, Italy
| | - Enzo Cadoni
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
| | - Norberto Masciocchi
- Dipartimento
di Scienza e Alta Tecnologia & To.Sca.Lab., Università degli Studi dell, via Valleggio 11, Como 22100, Italy
| | - Albano N. Carneiro Neto
- Phantom-g,
Department of Physics, CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro 3810-193, Portugal
| | - Luís D. Carlos
- Phantom-g,
Department of Physics, CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro 3810-193, Portugal
| | - Maria Laura Mercuri
- Dipartimento
di Scienze Chimiche e Geologiche, Università
degli Studi di Cagliari, Monserrato I-09042, Italy
- INSTM, Via Giuseppe Giusti, 9, Firenze 50121, Italy
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2
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Cappai A, Melis C, Marongiu D, Quochi F, Saba M, Congiu F, He Y, Slade TJ, Kanatzidis MG, Colombo L. Strong Anharmonicity at the Origin of Anomalous Thermal Conductivity in Double Perovskite Cs 2 NaYbCl 6. Adv Sci (Weinh) 2024; 11:e2305861. [PMID: 38111327 PMCID: PMC10916569 DOI: 10.1002/advs.202305861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/16/2023] [Indexed: 12/20/2023]
Abstract
Anomalous thermal transport of Cs2 NaYbCl6 double-halide perovskite above room temperature is reported and rationalized. Calculations of phonon dispersion relations and scattering rates up to the fourth order in lattice anharmonicity have been conducted to determine their effective dependence on temperature. These findings show that specific phonon group velocities and lifetimes increase if the temperature is raised above 500 K. This, in combination with anharmonicity, provides the microscopic mechanism responsible for the increase in lattice thermal conductivity at high temperatures, contrary to the predictions of phonon transport theories based on solely cubic anharmonicity. The model accurately and quantitatively reproduces the experimental thermal conductivity data as a function of temperature.
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Affiliation(s)
- Antonio Cappai
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
| | - Claudio Melis
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
| | - Daniela Marongiu
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
| | - Francesco Quochi
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
| | - Michele Saba
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
| | - Francesco Congiu
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
| | - Yihui He
- Department of ChemistryNorthwestern University2145 North Sheridan RoadEvanstonIL60208USA
| | - Tyler J. Slade
- Department of ChemistryNorthwestern University2145 North Sheridan RoadEvanstonIL60208USA
| | - Mercouri G. Kanatzidis
- Department of ChemistryNorthwestern University2145 North Sheridan RoadEvanstonIL60208USA
| | - Luciano Colombo
- Department of PhysicsUniversity of CagliariCittadella UniversitariaMonserrato (CA)09042Italy
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3
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Oggianu M, Abhervé A, Marongiu D, Quochi F, Galán-Mascarós JR, Bertolotti F, Masciocchi N, Avarvari N, Mercuri ML. Terbium and Europium Chlorocyananilate-Based 2D Coordination Polymers. Molecules 2023; 28:6453. [PMID: 37764229 PMCID: PMC10535540 DOI: 10.3390/molecules28186453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/29/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Two-dimensional layered coordination polymers based on the hetero-substituted 3-chloro-6-cyano-2,5-dihydroxybenzoquinone ligands, hereafter ClCNAn2- anilate, and LnIII ions (Tb and Eu) are reported. Compounds 1 and 2, formulated as Ln2(ClCNAn)3(DMSO)6 (LnIII = Tb, 1; Eu, 2), and their related intermediates 1' and 2', formulated as Ln2(ClCNAn)3(H2O)x·yH2O (x + y likely = 12, Ln = Tb, 1'; and Eu, 2'), were prepared by a conventional one-pot reaction (the latter) and recrystallized from DMSO solvent (the former). Polyhydrated intermediates 1' and 2' show very similar XRPD patterns, while, despite their common stoichiometry, 1 and 2 are not isostructural. Compound 1 consists of a 2D coordination framework of 3,6 topology, where [Tb(DMSO)3]III moieties are bridged by three bis-chelating ClCNAn2- ligands, forming distorted hexagons. Ultrathin nanosheets of 1 were obtained by exfoliation via the liquid-assisted sonication method and characterized by atomic force microscopy, confirming the 2D nature of 1. The crystal structure of 2, still showing the presence of 2D sheets with a "hexagonal" mesh and a common (3,6) connectivity, is based onto flat, non-corrugated slabs. Indeed, at a larger scale, the different "rectangular tiles" show clear roofing in 1, which is totally absent in 2. The magnetic behavior of 1 very likely indicates depopulation of the highest crystal-field levels, as expected for TbIII compounds.
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Affiliation(s)
- Mariangela Oggianu
- Department of Chemical and Geological Sciences, University of Cagliari, Highway 554, Crossroads for Sestu, I-09042 Monserrato, Italy;
- National Interuniversity Consortium of Materials Science and Technology, INSTM, Street Giuseppe Giusti, 9, I-50121 Florence, Italy; (F.Q.); (N.M.)
| | - Alexandre Abhervé
- Laboratoire MOLTECH-Anjou UMR 6200, UFR Sciences, CNRS, Université d’Angers, Bât. K, 2 Bd. Lavoisier, I-49045 Angers, France;
| | - Daniela Marongiu
- Department of Physics, University of Cagliari, Highway 554, Crossroads for Sestu, I-09042 Monserrato, Italy;
| | - Francesco Quochi
- National Interuniversity Consortium of Materials Science and Technology, INSTM, Street Giuseppe Giusti, 9, I-50121 Florence, Italy; (F.Q.); (N.M.)
- Department of Physics, University of Cagliari, Highway 554, Crossroads for Sestu, I-09042 Monserrato, Italy;
| | - José Ramón Galán-Mascarós
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Avenida Països Catalans 16, 43007 Tarragona, Spain;
- ICREA, Av. Lluis Companys 16, Passeig Lluís Companys, 23, 08010 Barcelona, Spain
| | - Federica Bertolotti
- Dipartimento di Scienza e Alta Tecnologia & To.Sca.Lab., University of Insubria, Via Valleggio 11, I-22100 Como, Italy;
| | - Norberto Masciocchi
- National Interuniversity Consortium of Materials Science and Technology, INSTM, Street Giuseppe Giusti, 9, I-50121 Florence, Italy; (F.Q.); (N.M.)
- Dipartimento di Scienza e Alta Tecnologia & To.Sca.Lab., University of Insubria, Via Valleggio 11, I-22100 Como, Italy;
| | - Narcis Avarvari
- Laboratoire MOLTECH-Anjou UMR 6200, UFR Sciences, CNRS, Université d’Angers, Bât. K, 2 Bd. Lavoisier, I-49045 Angers, France;
| | - Maria Laura Mercuri
- Department of Chemical and Geological Sciences, University of Cagliari, Highway 554, Crossroads for Sestu, I-09042 Monserrato, Italy;
- National Interuniversity Consortium of Materials Science and Technology, INSTM, Street Giuseppe Giusti, 9, I-50121 Florence, Italy; (F.Q.); (N.M.)
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4
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Simbula A, Wu L, Pitzalis F, Pau R, Lai S, Liu F, Matta S, Marongiu D, Quochi F, Saba M, Mura A, Bongiovanni G. Exciton dissociation in 2D layered metal-halide perovskites. Nat Commun 2023; 14:4125. [PMID: 37433858 DOI: 10.1038/s41467-023-39831-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 06/29/2023] [Indexed: 07/13/2023] Open
Abstract
Layered 2D perovskites are making inroads as materials for photovoltaics and light emitting diodes, but their photophysics is still lively debated. Although their large exciton binding energies should hinder charge separation, significant evidence has been uncovered for an abundance of free carriers among optical excitations. Several explanations have been proposed, like exciton dissociation at grain boundaries or polaron formation, without clarifying yet if excitons form and then dissociate, or if the formation is prevented by competing relaxation processes. Here we address exciton stability in layered Ruddlesden-Popper PEA2PbI4 (PEA stands for phenethylammonium) both in form of thin film and single crystal, by resonant injection of cold excitons, whose dissociation is then probed with femtosecond differential transmission. We show the intrinsic nature of exciton dissociation in 2D layered perovskites, demonstrating that both 2D and 3D perovskites are free carrier semiconductors and their photophysics is described by a unique and universal framework.
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Affiliation(s)
- Angelica Simbula
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy.
| | - Luyan Wu
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Federico Pitzalis
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Riccardo Pau
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 09747, AG, Groningen, The Netherlands
| | - Stefano Lai
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Fang Liu
- School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Selene Matta
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Daniela Marongiu
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Francesco Quochi
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Michele Saba
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy.
| | - Andrea Mura
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
| | - Giovanni Bongiovanni
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, CA, I-09042, Italy
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5
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Monni N, Baldoví JJ, García-López V, Oggianu M, Cadoni E, Quochi F, Clemente-León M, Mercuri ML, Coronado E. Reversible tuning of luminescence and magnetism in a structurally flexible erbium–anilato MOF. Chem Sci 2022; 13:7419-7428. [PMID: 35872828 PMCID: PMC9242018 DOI: 10.1039/d2sc00769j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/10/2022] [Indexed: 12/26/2022] Open
Abstract
By combining 3,6-N-ditriazolyl-2,5-dihydroxy-1,4-benzoquinone (H2trz2An) with NIR-emitting ErIII ions, two different 3D neutral polymorphic frameworks (1a and 1b), differing in the number of uncoordinated water molecules, formulated as [Er2(trz2An)3(H2O)4]n·xH2O (x = 10, a; x = 7, b), have been obtained. The structure of 1a shows layers with (6,3) topology forming six-membered rings with distorted hexagonal cavities along the bc plane. These 2D layers are interconnected through the N4 atoms of the two pendant arms of the trz2An linkers, leading to a 3D framework, where neighboring layers are eclipsed along the a axis, with hexagonal channels filled with water molecules. In 1b, layers with (6,3) topology in the [101] plane are present, each ErIII ion being connected to three other ErIII ions through bis-bidentate trz2An linkers, forming rectangular six-membered cavities. 1a and 1b are multifunctional materials showing coexistence of NIR emission and field-induced slow relaxation of the magnetization. Remarkably, 1a is a flexible MOF, showing a reversible structural phase transition involving shrinkage/expansion from a distorted hexagonal 2D framework to a distorted 3,6-brickwall rectangular 3D structure in [Er2(trz2An)3(H2O)2]n·2H2O (1a_des). This transition is triggered by a dehydration/hydration process under mild conditions (vacuum/heating to 360 K). The partially dehydrated compound shows a sizeable change in the emission properties and an improvement of the magnetic blocking temperature with respect to the hydrated compound, mainly related to the loss of one water coordination molecule. Theoretical calculations support the experimental findings, indicating that the slight improvement observed in the magnetic properties has its origin in the change of the ligand field around the ErIII ion due to the loss of a water molecule. Tuning of luminescent and SIM properties is herein reported, in a novel flexible 3D anilato-based ErIII-MOF, displaying reversible shrinkage/expansion from a distorted hexagonal to a 3,6-brickwall rectangular structure.![]()
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Affiliation(s)
- Noemi Monni
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, 09042 Monserrato, Italy
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980 Paterna, Spain
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, INSTM, Via Giusti 9, 50121 Firenze, Italy
| | - José J. Baldoví
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Víctor García-López
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Mariangela Oggianu
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, 09042 Monserrato, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, INSTM, Via Giusti 9, 50121 Firenze, Italy
| | - Enzo Cadoni
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, 09042 Monserrato, Italy
| | - Francesco Quochi
- Dipartimento di Fisica, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, 09042 Monserrato, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, INSTM, Via Giusti 9, 50121 Firenze, Italy
| | - Miguel Clemente-León
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Maria Laura Mercuri
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, 09042 Monserrato, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, INSTM, Via Giusti 9, 50121 Firenze, Italy
| | - Eugenio Coronado
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980 Paterna, Spain
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6
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Ashoka Sahadevan S, Manna F, Abhervé A, Oggianu M, Monni N, Mameli V, Marongiu D, Quochi F, Gendron F, Le Guennic B, Avarvari N, Mercuri ML. Combined Experimental/Theoretical Study on the Luminescent Properties of Homoleptic/Heteroleptic Erbium(III) Anilate-Based 2D Coordination Polymers. Inorg Chem 2021; 60:17765-17774. [PMID: 34784217 DOI: 10.1021/acs.inorgchem.1c02386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis, structural and photophysical characterization, and theoretical studies on homo/heteroleptic neutral 2D-layered coordination polymers (CPs), obtained by combining the ErIII ion with chlorocyananilate (ClCNAn) and/or tetrafluoroterephthalate (F4BDC) linkers, are herein reported. The structure of the heteroleptic ErIII-based CP, formulated as [Er2(ClCNAn)2(F4BDC)(DMSO)6]n (1) is also reported. 1 crystallizes in the triclinic P1̅ space group, and the structure consists of neutral 2D layers formed by ErIII ions linked through the two linkers oriented in such a way that the neighboring 2D layers are eclipsed along the a axis, leading to parallelogram-like cavities. Photophysical measurements highlight the prominent role of chlorocyananilate linkers as optical antennas toward lanthanide ions, while wave-function-theory analysis supports the experimental findings, providing evidence for the effect of ligand substitution on the luminescence properties of homo/heteroleptic 2D CPs.
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Affiliation(s)
- Suchithra Ashoka Sahadevan
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554, Bivio per Sestu, Monserrato, Cagliari I-09042, Italy.,Univ Angers, CNRS, MOLTECH-Anjou, SFR MATRIX, F-49000 Angers, France
| | - Fabio Manna
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554, Bivio per Sestu, Monserrato, Cagliari I-09042, Italy
| | - Alexandre Abhervé
- Univ Angers, CNRS, MOLTECH-Anjou, SFR MATRIX, F-49000 Angers, France
| | - Mariangela Oggianu
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554, Bivio per Sestu, Monserrato, Cagliari I-09042, Italy.,Consorzio Interuniversitario Nazionale per La Scienza e Tecnologia Dei Materiali (INSTM), Cagliari Unit, Via Giuseppe Giusti 9, Firenze 50121, Italy
| | - Noemi Monni
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554, Bivio per Sestu, Monserrato, Cagliari I-09042, Italy.,Consorzio Interuniversitario Nazionale per La Scienza e Tecnologia Dei Materiali (INSTM), Cagliari Unit, Via Giuseppe Giusti 9, Firenze 50121, Italy
| | - Valentina Mameli
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554, Bivio per Sestu, Monserrato, Cagliari I-09042, Italy.,Consorzio Interuniversitario Nazionale per La Scienza e Tecnologia Dei Materiali (INSTM), Cagliari Unit, Via Giuseppe Giusti 9, Firenze 50121, Italy
| | - Daniela Marongiu
- Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, Cagliari I-09042, Italy
| | - Francesco Quochi
- Consorzio Interuniversitario Nazionale per La Scienza e Tecnologia Dei Materiali (INSTM), Cagliari Unit, Via Giuseppe Giusti 9, Firenze 50121, Italy.,Dipartimento di Fisica, Università degli Studi di Cagliari, Monserrato, Cagliari I-09042, Italy
| | - Frédéric Gendron
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France
| | - Boris Le Guennic
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France
| | - Narcis Avarvari
- Univ Angers, CNRS, MOLTECH-Anjou, SFR MATRIX, F-49000 Angers, France
| | - Maria Laura Mercuri
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554, Bivio per Sestu, Monserrato, Cagliari I-09042, Italy.,Consorzio Interuniversitario Nazionale per La Scienza e Tecnologia Dei Materiali (INSTM), Cagliari Unit, Via Giuseppe Giusti 9, Firenze 50121, Italy
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7
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Lehmann AG, Congiu F, Marongiu D, Mura A, Filippetti A, Mattoni A, Saba M, Pegna G, Sarritzu V, Quochi F, Bongiovanni G. Long-lived electrets and lack of ferroelectricity in methylammonium lead bromide CH 3NH 3PbBr 3 ferroelastic single crystals. Phys Chem Chem Phys 2021; 23:3233-3245. [PMID: 33465210 DOI: 10.1039/d0cp05918h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hybrid lead halides CH3NH3PbX3 (X = I, Br, and Cl) have emerged as a new class of semiconductors for low-cost optoelectronic devices with superior performance. Since their perovskite crystal structure may have lattice instabilities against polar distortions, they are also being considered as potential photo-ferroelectrics. However, so far, research on their ferroelectricity has yielded inconclusive results and the subject is far from being settled. Here, we investigate, using a combined experimental and theoretical approach, the possible presence of electric polarization in tetragonal and orthorhombic CH3NH3PbBr3 (T-MAPB and O-MAPB). We found that T-MAPB does not sustain spontaneous polarization but, under an external electric field, it is projected into a metastable, ionic space-charge electret state. The electret can be frozen on cooling, producing a large and long-lasting polarization in O-MAPB. Molecular dynamics simulations show that the ferroelastic domain boundaries are able to trap charges and segregate ionic point defects, thus playing a favorable role in the stabilization of the electret. At lower temperatures, the lack of ferroelectric behavior is explained using first principles calculations as the result of the tight competition among many metastable states with randomly oriented polarization; this large configurational entropy does not allow a single polar state to dominate at any significant temperature range.
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8
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Oggianu M, Figus C, Ashoka-Sahadevan S, Monni N, Marongiu D, Saba M, Mura A, Bongiovanni G, Caltagirone C, Lippolis V, Cannas C, Cadoni E, Mercuri ML, Quochi F. Silicon-based fluorescent platforms for copper(ii) detection in water. RSC Adv 2021; 11:15557-15564. [PMID: 35481193 PMCID: PMC9029085 DOI: 10.1039/d1ra02695j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 04/19/2021] [Indexed: 12/23/2022] Open
Abstract
The potential of silicon-based fluorescent platforms for the detection of trace toxic metal ions was investigated in an aqueous environment. To this aim, silicon chips were first functionalized with amino groups, and fluorescein organic dyes, used as sensing molecules, were then covalently linked to the surface via formation of thiourea groups. The obtained hybrid heterostructures exhibited high sensitivity and selectivity towards copper(ii), a limit of detection compatible with the recommended upper limits for copper in drinking water, and good reversibility using a standard metal–chelating agent. The fluorophore–analyte interaction mechanism at the basis of the reported fluorescence quenching, as well as the potential of performance improvement, were also studied. The herein presented sensing architecture allows, in principle, tailoring of the selectivity towards other metal ions by proper fluorophore selection, and provides a favorable outlook for integration of fluorescent chemosensors with silicon photonics technology. Covalent linkage of fluorescein to silanized silicon chips yields solid-state platforms for detection of copper(ii) in water. This architecture represents a step forward towards the fabrication of sensors for remote water analysis applications.![]()
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9
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Marongiu D, Lai S, Sarritzu V, Pinna E, Mula G, Mercuri ML, Saba M, Quochi F, Mura A, Bongiovanni G. Bifacial Diffuse Absorptance of Semitransparent Microstructured Perovskite Solar Cells. ACS Appl Mater Interfaces 2019; 11:10021-10027. [PMID: 30768241 DOI: 10.1021/acsami.8b22285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
An optical radiometry technique enabling simultaneous transmittance and reflectance measurements from both sides of a device was used to investigate bifacial diffuse absorptance of neutral-colored semitransparent perovskite solar cells based on a thin film of microsized perovskite islands. In such microstructured solar cells, diffuse irradiance was more effectively absorbed than direct irradiance at near-normal incidence, in contrast to reference solar cells comprising a continuous perovskite thin film. Experimental findings were discussed in ray-optic approximation in relation to the surface texture of the active layer, highlighting the role of light trapping. This absorptance spectroscopy technique is envisaged to find wide applicability to bifacial solar cells for building-integrated photovoltaics and other bifacial light-harvesting systems.
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Affiliation(s)
| | | | | | | | | | | | | | - Francesco Quochi
- INSTM , Cagliari Unit , Via Giuseppe Giusti, 9 , I-50121 Firenze , Italy
| | - Andrea Mura
- INSTM , Cagliari Unit , Via Giuseppe Giusti, 9 , I-50121 Firenze , Italy
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10
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Sarritzu V, Sestu N, Marongiu D, Chang X, Masi S, Rizzo A, Colella S, Quochi F, Saba M, Mura A, Bongiovanni G. Optical determination of Shockley-Read-Hall and interface recombination currents in hybrid perovskites. Sci Rep 2017; 7:44629. [PMID: 28317883 PMCID: PMC5357960 DOI: 10.1038/srep44629] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 02/10/2017] [Indexed: 12/20/2022] Open
Abstract
Metal-halide perovskite solar cells rival the best inorganic solar cells in power conversion efficiency, providing the outlook for efficient, cheap devices. In order for the technology to mature and approach the ideal Shockley-Queissier efficiency, experimental tools are needed to diagnose what processes limit performances, beyond simply measuring electrical characteristics often affected by parasitic effects and difficult to interpret. Here we study the microscopic origin of recombination currents causing photoconversion losses with an all-optical technique, measuring the electron-hole free energy as a function of the exciting light intensity. Our method allows assessing the ideality factor and breaks down the electron-hole recombination current into bulk defect and interface contributions, providing an estimate of the limit photoconversion efficiency, without any real charge current flowing through the device. We identify Shockley-Read-Hall recombination as the main decay process in insulated perovskite layers and quantify the additional performance degradation due to interface recombination in heterojunctions.
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Affiliation(s)
- Valerio Sarritzu
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Nicola Sestu
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Daniela Marongiu
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Xueqing Chang
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Sofia Masi
- Istituto di Nanotecnologia CNR-Nanotec, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce, Italy
| | - Aurora Rizzo
- Istituto di Nanotecnologia CNR-Nanotec, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce, Italy
| | - Silvia Colella
- Istituto di Nanotecnologia CNR-Nanotec, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce, Italy.,Dipartimento di Matematica e Fisica "E. De Giorgi", Università del Salento, Via Arnesano snc, 73100 Lecce, Italy
| | - Francesco Quochi
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Michele Saba
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Andrea Mura
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Giovanni Bongiovanni
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
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11
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Sarritzu V, Cadelano M, Sestu N, Marongiu D, Piras R, Chang X, Quochi F, Saba M, Mura A, Bongiovanni G. Paving the way for solution- processable perovskite lasers. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/pssc.201600134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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12
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Abstract
Metal halide perovskites have come to the attention of the scientific community for the progress achieved in solar light conversion. Energy sustainability is one of the priorities of our society, and materials advancements resulting in low-cost but efficient solar cells and large-area lighting devices represent a major goal for applied research. From a basic point of view, perovskites are an exotic class of hybrid materials combining some merits of organic and inorganic semiconductors: large optical absorption, large mobilities, and tunable band gap together with the possibility to be processed in solution. When a novel class of promising semiconductors comes into the limelight, lively discussions ensue on the photophysics of band-edge excitations, because just the states close to the band edge are entailed in energy/charge transport and light emission. This was the case several decades ago for III-V semiconductors, it has been up to 10 years ago for organics, and it is currently the case for perovskites. Our aim in this Account is to rationalize the body of experimental evidence on perovskite photophysics in a coherent theoretical framework, borrowing from the knowledge acquired over the years in materials optoelectronics. A crucial question is whether photon absorption leads to a population of unbound, conductive free charges or instead excitons, neutral and insulating bound states created by Coulomb interaction just below the energy of the band gap. We first focus on the experimental estimates of the exciton binding energy (Eb): at room temperature, Eb is comparable to the thermal energy kBT in MAPbI3 and increases up to values 2-3kBT in wide band gap MAPbBr3 and MAPbCl3. Statistical considerations predict that these values, even though comparable to or larger than thermal energy, let free carriers prevail over bound excitons for all levels of excitation densities relevant for devices. The analysis of photophysics evidence confirms that all hybrid halide perovskites behave as free-charge semiconductors. Thanks to such property, in combination with band gap energies covering the entire solar spectrum, perovskites represent a promising materials platform for highly efficient, single and multijunction solar cells. Concerning the use of perovskites as color-tunable materials in light emitting devices, free-charges are not the preferred species, as they recombine radiatively through a bimolecular process that is inefficient at the charge-injection levels typical of LED operation. Strategies to overcome this limit, and thus extend the use of perovskite materials beyond solar energy conversion, could be borrowed from inorganic semiconductor optoelectronics and include the fabrication of nanostructures with reduced dimensionality to alter the electronic density of states, as well as engineering composite materials.
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Affiliation(s)
- Michele Saba
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Francesco Quochi
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Andrea Mura
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
| | - Giovanni Bongiovanni
- Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy
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13
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Sestu N, Cadelano M, Sarritzu V, Chen F, Marongiu D, Piras R, Mainas M, Quochi F, Saba M, Mura A, Bongiovanni G. Absorption F-sum rule for the exciton binding energy in methylammonium lead halide perovskites. J Phys Chem Lett 2015; 6:4566-72. [PMID: 26517760 DOI: 10.1021/acs.jpclett.5b02099] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Advances of optoelectronic devices based on methylammonium lead halide perovskites depend on understanding the role of excitons, whether it is marginal as in inorganic semiconductors, or crucial, like in organics. However, a consensus on the exciton binding energy and its temperature dependence is still lacking, even for widely studied methylammonium lead iodide and bromide materials (MAPbI3, MAPbBr3). Here we determine the exciton binding energy based on an f-sum rule for integrated UV-vis absorption spectra, circumventing the pitfalls of least-squares fitting procedures. In the temperature range 80-300 K, we find that the exciton binding energy in MAPbBr3 is EB = (60 ± 3) meV, independent of temperature; for MAPbI3, in the orthorhombic phase (below 140 K) EB = (34 ± 3) meV, while in the tetragonal phase the binding energy softens to 29 meV at 170 K and stays constant up to 300 K. Implications of binding energy values on solar cell and LED workings are discussed.
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Affiliation(s)
- Nicola Sestu
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Michele Cadelano
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Valerio Sarritzu
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Feipeng Chen
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Daniela Marongiu
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Roberto Piras
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Marina Mainas
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Francesco Quochi
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Michele Saba
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Andrea Mura
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
| | - Giovanni Bongiovanni
- Dipartimento di Fisica, Università degli Studi di Cagliari , I-09042 Monserrato, Italy
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14
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Tavares L, Cadelano M, Quochi F, Simbrunner C, Schwabegger G, Saba M, Mura A, Bongiovanni G, Filho DADS, da Cunha W, Rubahn HG, Kjelstrup-Hansen J. Efficient Exciton Diffusion and Resonance-Energy Transfer in Multilayered Organic Epitaxial Nanofibers. J Phys Chem C Nanomater Interfaces 2015; 119:15689-15697. [PMID: 26191119 PMCID: PMC4500454 DOI: 10.1021/acs.jpcc.5b02405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 06/10/2015] [Indexed: 06/04/2023]
Abstract
Multilayered epitaxial nanofibers are exemplary model systems for the study of exciton dynamics and lasing in organic materials because of their well-defined morphology, high luminescence efficiencies, and color tunability. We use temperature-dependent continuous wave and picosecond photoluminescence (PL) spectroscopy to quantify exciton diffusion and resonance-energy transfer (RET) processes in multilayered nanofibers consisting of alternating layers of para-hexaphenyl (p6P) and α-sexithiophene (6T) serving as exciton donor and acceptor material, respectively. The high probability for RET processes is confirmed by quantum chemical calculations. The activation energy for exciton diffusion in p6P is determined to be as low as 19 meV, proving p6P epitaxial layers also as a very suitable donor material system. The small activation energy for exciton diffusion of the p6P donor material, the inferred high p6P-to-6T resonance-energy-transfer efficiency, and the observed weak PL temperature dependence of the 6T acceptor material together result in an exceptionally high optical emission performance of this all-organic material system, thus making it well suited, for example, for organic light-emitting devices.
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Affiliation(s)
- Luciana Tavares
- NanoSYD,
Mads Clausen Institute, University of Southern
Denmark, Alsion 2, DK-6400 Sønderborg, Denmark
| | - Michele Cadelano
- Department
of Physics, University of Cagliari, Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy
| | - Francesco Quochi
- Department
of Physics, University of Cagliari, Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy
| | - Clemens Simbrunner
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University Linz, A-4040 Linz, Austria
- Institute
of Solid State Physics, University of Bremen, D-28359 Bremen, Germany
| | - Günther Schwabegger
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University Linz, A-4040 Linz, Austria
| | - Michele Saba
- Department
of Physics, University of Cagliari, Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy
| | - Andrea Mura
- Department
of Physics, University of Cagliari, Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy
| | - Giovanni Bongiovanni
- Department
of Physics, University of Cagliari, Complesso Universitario di Monserrato, I-09042 Monserrato, Cagliari, Italy
| | | | | | - Horst-Günter Rubahn
- NanoSYD,
Mads Clausen Institute, University of Southern
Denmark, Alsion 2, DK-6400 Sønderborg, Denmark
| | - Jakob Kjelstrup-Hansen
- NanoSYD,
Mads Clausen Institute, University of Southern
Denmark, Alsion 2, DK-6400 Sønderborg, Denmark
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15
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Artizzu F, Quochi F, Marchiò L, Correia RF, Saba M, Serpe A, Mura A, Mercuri ML, Bongiovanni G, Deplano P. Cover Picture: Ln 3Q 9as a Molecular Framework for Ion-Size-Driven Assembly of Heterolanthanide (Nd, Er, Yb) Multiple Near-Infrared Emitters (Chem. Eur. J. 10/2015). Chemistry 2015. [DOI: 10.1002/chem.404435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Artizzu F, Quochi F, Marchiò L, Correia RF, Saba M, Serpe A, Mura A, Mercuri ML, Bongiovanni G, Deplano P. Ln 3Q 9as a Molecular Framework for Ion-Size-Driven Assembly of Heterolanthanide (Nd, Er, Yb) Multiple Near-Infrared Emitters. Chemistry 2015. [DOI: 10.1002/chem.201406660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Figus C, Patrini M, Floris F, Fornasari L, Pellacani P, Marchesini G, Valsesia A, Artizzu F, Marongiu D, Saba M, Marabelli F, Mura A, Bongiovanni G, Quochi F. Synergic combination of the sol-gel method with dip coating for plasmonic devices. Beilstein J Nanotechnol 2015; 6:500-507. [PMID: 25821692 PMCID: PMC4362208 DOI: 10.3762/bjnano.6.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/22/2015] [Indexed: 06/04/2023]
Abstract
Biosensing technologies based on plasmonic nanostructures have recently attracted significant attention due to their small dimensions, low-cost and high sensitivity but are often limited in terms of affinity, selectivity and stability. Consequently, several methods have been employed to functionalize plasmonic surfaces used for detection in order to increase their stability. Herein, a plasmonic surface was modified through a controlled, silica platform, which enables the improvement of the plasmonic-based sensor functionality. The key processing parameters that allow for the fine-tuning of the silica layer thickness on the plasmonic structure were studied. Control of the silica coating thickness was achieved through a combined approach involving sol-gel and dip-coating techniques. The silica films were characterized using spectroscopic ellipsometry, contact angle measurements, atomic force microscopy and dispersive spectroscopy. The effect of the use of silica layers on the optical properties of the plasmonic structures was evaluated. The obtained results show that the silica coating enables surface protection of the plasmonic structures, preserving their stability for an extended time and inducing a suitable reduction of the regeneration time of the chip.
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Affiliation(s)
- Cristiana Figus
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
| | - Maddalena Patrini
- University of Pavia, Department of Physics, Via Agostino Bassi 6, 27100 Pavia, Italy
| | - Francesco Floris
- University of Pavia, Department of Physics, Via Agostino Bassi 6, 27100 Pavia, Italy
| | - Lucia Fornasari
- University of Pavia, Department of Physics, Via Agostino Bassi 6, 27100 Pavia, Italy
| | | | | | | | - Flavia Artizzu
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
- University of Cagliari, Department of Chemistry and Geology, S.P. Monserrato-Sestu Km 0.700, 09042 Monserrato, Cagliari, Italy
| | - Daniela Marongiu
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
| | - Michele Saba
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
| | - Franco Marabelli
- University of Pavia, Department of Physics, Via Agostino Bassi 6, 27100 Pavia, Italy
| | - Andrea Mura
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
| | - Giovanni Bongiovanni
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
| | - Francesco Quochi
- University of Cagliari, Department of Physics, S.P. Monserrato-Sestu Km 0.7, 09042 Monserrato, Italy
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18
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Abstract
Three classes of heterolanthanide assemblies, multi-dimensional frameworks (A), discrete polynuclear molecules (B) and preformed coordinated units connected by a linker (C), are discussed. Potential functionalities arising from the distance-dependent coexistence or interplay of the physical properties are pointed out.
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Affiliation(s)
- Flavia Artizzu
- Dipartimento di Scienze Chimiche e Geologiche
- University of Cagliari
- Monserrato-Cagliari
- Italy
- Dipartimento di Fisica
| | - Francesco Quochi
- Dipartimento di Fisica
- University of Cagliari
- Monserrato-Cagliari
- Italy
| | - Angela Serpe
- Dipartimento di Scienze Chimiche e Geologiche
- University of Cagliari
- Monserrato-Cagliari
- Italy
| | - Elisa Sessini
- Dipartimento di Scienze Chimiche e Geologiche
- University of Cagliari
- Monserrato-Cagliari
- Italy
| | - Paola Deplano
- Dipartimento di Scienze Chimiche e Geologiche
- University of Cagliari
- Monserrato-Cagliari
- Italy
- Dipartimento di Fisica
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19
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Piras R, Aresti M, Saba M, Marongiu D, Mula G, Quochi F, Mura A, Cannas C, Mureddu M, Ardu A, Ennas G, Calzia V, Mattoni A, Musinu A, Bongiovanni G. Colloidal synthesis and characterization of Bi2S3nanoparticles for photovoltaic applications. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/566/1/012017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Artizzu F, Quochi F, Marchiò L, Correia RF, Saba M, Serpe A, Mura A, Mercuri ML, Bongiovanni G, Deplano P. Ln3Q9as a Molecular Framework for Ion-Size-Driven Assembly of Heterolanthanide (Nd, Er, Yb) Multiple Near-Infrared Emitters. Chemistry 2014; 21:3882-5. [DOI: 10.1002/chem.201405634] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Indexed: 11/11/2022]
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21
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Floris F, Figus C, Fornasari L, Patrini M, Pellacani P, Marchesini G, Valsesia A, Artizzu F, Marongiu D, Saba M, Mura A, Bongiovanni G, Marabelli F, Quochi F. Optical Sensitivity Gain in Silica-Coated Plasmonic Nanostructures. J Phys Chem Lett 2014; 5:2935-2940. [PMID: 26278239 DOI: 10.1021/jz501443c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ultrathin films of silica realized by sol-gel synthesis and dip-coating techniques were successfully applied to predefined metal/polymer plasmonic nanostructures to spectrally tune their resonance modes and to increase their sensitivity to local refractive index changes. Plasmon resonance spectral shifts up to 100 nm with slope efficiencies of ∼8 nm/nm for increasing layer thickness were attained. In the ultrathin layer regime (<10 nm), which could be reached by suitable dilution of the silica precursors and optimization of the deposition speed, the sensitivity of the main plasmonic resonance to refractive index changes in aqueous solution could be increased by over 50% with respect to the bare plasmonic chip. Numerical simulations supported experimental data and unveiled the mechanism responsible for the optical sensitivity gain, proving an effective tool in the design of high-performance plasmonic sensors.
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Affiliation(s)
- Francesco Floris
- †Dipartimento di Fisica, Università degli Studi di Pavia, Via Bassi 6, I-27100 Pavia, Italy
| | - Cristiana Figus
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
| | - Lucia Fornasari
- †Dipartimento di Fisica, Università degli Studi di Pavia, Via Bassi 6, I-27100 Pavia, Italy
| | - Maddalena Patrini
- †Dipartimento di Fisica, Università degli Studi di Pavia, Via Bassi 6, I-27100 Pavia, Italy
| | | | | | | | - Flavia Artizzu
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
- ∥Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
| | - Daniela Marongiu
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
| | - Michele Saba
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
| | - Andrea Mura
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
| | - Giovanni Bongiovanni
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
| | - Franco Marabelli
- †Dipartimento di Fisica, Università degli Studi di Pavia, Via Bassi 6, I-27100 Pavia, Italy
| | - Francesco Quochi
- ‡Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato, Cagliari, Italy
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22
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Conca E, Aresti M, Saba M, Casula MF, Quochi F, Mula G, Loche D, Kim MR, Manna L, Corrias A, Mura A, Bongiovanni G. Charge separation in Pt-decorated CdSe@CdS octapod nanocrystals. Nanoscale 2014; 6:2238-2243. [PMID: 24424255 DOI: 10.1039/c3nr05567a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We synthesize colloidal CdSe@CdS octapod nanocrystals decorated with Pt domains, resulting in a metal-semiconductor heterostructure. We devise a protocol to control the growth of Pt on the CdS surface, realizing both a selective tipping and a non-selective coverage. Ultrafast optical spectroscopy, particularly femtosecond transient absorption, is employed to correlate the dynamics of optical excitations with the nanocrystal morphology. We find two regimes for capture of photoexcited electrons by Pt domains: a slow capture after energy relaxation in the semiconductor, occurring in tipped nanocrystals and resulting in large spatial separation of charges, and an ultrafast capture of hot electrons occurring in nanocrystals covered in Pt, where charge separation happens faster than energy relaxation and Auger recombination. Besides the relevance for fundamental materials science and control at the nanoscale, our nanocrystals may be employed in solar photocatalysis.
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Affiliation(s)
- Erika Conca
- Dipartimento di Scienze Chimiche e Geologiche and INSTM, Università di Cagliari, Cittadella universitaria, I-09042 Monserrato, Italy
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23
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Schwabegger G, Oehzelt M, Salzmann I, Quochi F, Saba M, Mura A, Bongiovanni G, Vollmer A, Koch N, Sitter H, Simbrunner C. Interface properties of organic para-hexaphenyl/α-sexithiophene heterostructures deposited on highly oriented pyrolytic graphite. Langmuir 2013; 29:14444-14450. [PMID: 24156627 PMCID: PMC3842851 DOI: 10.1021/la402242b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/23/2013] [Indexed: 06/02/2023]
Abstract
It was recently reported, that heterostructures of para-hexaphenyl (p-6P) and α-sexithiophene (6T) deposited on muscovite mica exhibit the intriguing possibility to prepare lasing nanofibers of tunable emission wavelength. For p-6P/6T heterostructures, two different types of 6T emission have been observed, namely, the well-known red emission of bulk 6T crystals and additionally a green emission connected to the interface between p-6P and 6T. In this study, the origin of the green fluorescence is investigated by photoelectron spectroscopy (PES). As a prerequisite, it is necessary to prepare structurally similar organic crystals on a conductive surface, which leads to the choice of highly oriented pyrolytic graphite (HOPG) as a substrate. The similarity between p-6P/6T heterostructures on muscovite mica and on HOPG is evidenced by X-ray diffraction (XRD), scanning force microscopy (SFM), and optical spectroscopy. PES measurements show that the interface between p-6P and 6T crystals is sharp on a molecular level without any sign of interface dipole formation or chemical interaction between the molecules. We therefore conclude that the different emission colors of the two 6T phases are caused by different types of molecular aggregation.
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Affiliation(s)
- Günther Schwabegger
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
| | - Martin Oehzelt
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, BESSY II, D-12489 Berlin, Germany
- Institut
für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany
| | - Ingo Salzmann
- Institut
für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany
| | - Francesco Quochi
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
| | - Michele Saba
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
| | - Andrea Mura
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
| | - Giovanni Bongiovanni
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
- Istituto
Officina dei Materiali (CNR-IOM), Unità
di Cagliari, I-09042 Monserrato (CA), Italy
| | - Antje Vollmer
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, BESSY II, D-12489 Berlin, Germany
| | - Norbert Koch
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, BESSY II, D-12489 Berlin, Germany
- Institut
für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany
| | - Helmut Sitter
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
| | - Clemens Simbrunner
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
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24
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Simbrunner C, Hernandez-Sosa G, Quochi F, Schwabegger G, Botta C, Oehzelt M, Salzmann I, Djuric T, Neuhold A, Resel R, Saba M, Mura A, Bongiovanni G, Vollmer A, Koch N, Sitter H. Color tuning of nanofibers by periodic organic-organic hetero-epitaxy. ACS Nano 2012; 6:4629-38. [PMID: 22594789 PMCID: PMC3395255 DOI: 10.1021/nn2047235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We report on the epitaxial growth of periodic para-hexaphenyl (p-6P)/α-sexi-thiophene (6T) multilayer heterostructures on top of p-6P nanotemplates. By the chosen approach, 6T molecules are forced to align parallel to the p-6P template molecules, which yields highly polarized photoluminescence (PL)-emission of both species. The PL spectra show that the fabricated multilayer structures provide optical emission from two different 6T phases, interfacial 6T molecules, and 3-dimensional crystallites. By a periodical deposition of 6T monolayers and p-6P spacers it is demonstrated that the strongly polarized spectral contribution of interfacial 6T can be precisely controlled and amplified. By analyzing the PL emission of both 6T phases as a function of p-6P spacer thickness (Δd(p-6P)) we have determined a critical value of Δd(p-6P )≈ 2.73 nm where interfacial 6T runs into saturation and the surplus of 6T starts to cluster in 3-dimensional crystallites. These results are further substantiated by UPS and XRD measurements. Moreover, it is demonstrated by morphological investigations, provided by scanning force microscopy and fluorescence microscopy, that periodical deposition of 6T and p-6P leads to a significant improvement of homogeneity in PL-emission and morphology of nanofibers. Photoluminescence excitation experiments in combination with time-resolved photoluminescence demonstrate that the spectral emission of the organic multilayer nanofibers is dominated by a resonant energy transfer from p-6P host- to 6T guest-molecules. The sensitization time of the 6T emission in the 6T/p-6P multilayer structures depends on the p-6P spacer thickness, and can be explained by well separated layers of host-guest molecules obtained by organic-organic heteroepitaxy. The spectral emission and consequently the fluorescent color of the nanofibers can be efficiently tuned from the blue via white to the yellow-green spectral range.
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Affiliation(s)
- Clemens Simbrunner
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Austria.
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25
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Artizzu F, Quochi F, Saba M, Marchiò L, Espa D, Serpe A, Mura A, Mercuri ML, Bongiovanni G, Deplano P. Dual Emitting [Yb(5,7ClQ)2(H5,7ClQ)2Cl]: Chemical and Photophysical Properties. Chempluschem 2012. [DOI: 10.1002/cplu.201200006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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26
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Marceddu M, Saba M, Quochi F, Lai A, Huang J, Talapin DV, Mura A, Bongiovanni G. Charged excitons, Auger recombination and optical gain in CdSe/CdS nanocrystals. Nanotechnology 2012; 23:015201. [PMID: 22156236 DOI: 10.1088/0957-4484/23/1/015201] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
CdSe/CdS colloidal nanocrystals are members of a novel class of light-emitting nanoparticles with remarkable optical properties such as suppressed fluorescence blinking and enhanced emission from multiexciton states. These properties have been linked to the suppression of non-radiative Auger recombination. In this work we employ ultrafast spectroscopy techniques to identify optical signatures of neutral and charged excitonic and multiexcitonic states. We show that Auger recombination of biexcitons is not suppressed, while we observe optical gain and amplified spontaneous emission from multiexciton states and from long-lived charged-exciton states.
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Affiliation(s)
- Marco Marceddu
- Centro Grandi Strumenti d'Ateneo, Università di Cagliari, Monserrato (CA), Italy
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27
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Artizzu F, Quochi F, Saba M, Loche D, Mercuri ML, Serpe A, Mura A, Bongiovanni G, Deplano P. Silica sol–gel glasses incorporating dual-luminescent Yb quinolinolato complex: processing, emission and photosensitising properties of the ‘antenna’ ligand. Dalton Trans 2012; 41:13147-53. [PMID: 23007128 DOI: 10.1039/c2dt30323j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Flavia Artizzu
- Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Monserrato-Cagliari, Italy.
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28
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Simbrunner C, Quochi F, Hernandez-Sosa G, Oehzelt M, Resel R, Hesser G, Arndt M, Saba M, Mura A, Bongiovanni G, Sitter H. Organic-organic heteroepitaxy of red-, green-, and blue-emitting nanofibers. ACS Nano 2010; 4:6244-50. [PMID: 20879745 DOI: 10.1021/nn1018889] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Self-assembly processes and organic-organic heteroepitaxy are powerful techniques to obtain highly ordered molecular aggregates. Here we demonstrate that combining both methods allows not only to fabricate highly crystalline and uniaxially oriented self-assembled nanofibers but also to tune their polarized emission. We show that submonolayer coverage of sexithiophene on top of para-sexiphenyl nanofibers is sufficient to change their emission color from blue to green. Triband emission in the red, green, and blue is generated in nanofibers with thicker sexithiophene coverage, where layers of co-oriented crystals are separated by green-emitting molecular sheets.
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Affiliation(s)
- Clemens Simbrunner
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Austria.
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29
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Saba M, Minniberger S, Quochi F, Roither J, Marceddu M, Gocalinska A, Kovalenko MV, Talapin DV, Heiss W, Mura A, Bongiovanni G. Exciton-Exciton Interaction and Optical Gain in Colloidal CdSe/CdS Dot/Rod Nanocrystals. Adv Mater 2009; 21:4942-4946. [PMID: 25376736 DOI: 10.1002/adma.200901482] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Indexed: 05/27/2023]
Abstract
Exciton-exciton interaction in dot/rod CdSe/CdS nanocrystals has proved to be very sensitive to the shape of nanocrystals, due to the unique band alignment between CdSe and CdS. Repulsive exciton-exciton interaction is demonstrated, which makes CdSe/CdS dot/rods promising gain media for solution-processable lasers, with projected pump threshold densities below 1 kW cm(-2) for continuous wave lasing.
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Affiliation(s)
- Michele Saba
- Dipartimento di Fisica and SLACS-CNR/INFM, Università di Cagliari 09042 Monserrato (Italy)
| | - Stefan Minniberger
- Institute of Semiconductor and Solid State Physics Johannes Kepler University Altenbergerstr. 6g, 4040 Linz (Austria)
| | - Francesco Quochi
- Dipartimento di Fisica and SLACS-CNR/INFM, Università di Cagliari 09042 Monserrato (Italy)
| | - Juergen Roither
- Institute of Semiconductor and Solid State Physics Johannes Kepler University Altenbergerstr. 6g, 4040 Linz (Austria)
| | - Marco Marceddu
- Dipartimento di Fisica and SLACS-CNR/INFM, Università di Cagliari 09042 Monserrato (Italy)
| | - Agnieszka Gocalinska
- Dipartimento di Fisica and SLACS-CNR/INFM, Università di Cagliari 09042 Monserrato (Italy)
| | - Maksym V Kovalenko
- Department of Chemistry, The University of Chicago Chicago, IL 60637 (USA)
| | - Dmitri V Talapin
- Department of Chemistry, The University of Chicago Chicago, IL 60637 (USA)
| | - Wolfgang Heiss
- Institute of Semiconductor and Solid State Physics Johannes Kepler University Altenbergerstr. 6g, 4040 Linz (Austria)
| | - Andrea Mura
- Dipartimento di Fisica and SLACS-CNR/INFM, Università di Cagliari 09042 Monserrato (Italy)
| | - Giovanni Bongiovanni
- Dipartimento di Fisica and SLACS-CNR/INFM, Università di Cagliari 09042 Monserrato (Italy)
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30
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Giorgetti E, Giusti A, Arias E, Moggio I, Ledezma A, Romero J, Saba M, Quochi F, Marceddu M, Gocalinska A, Mura A, Bongiovanni G. In Situ Production of Polymer-Capped Silver Nanoparticles for Optical Biosensing. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/masy.200950922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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31
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Abstract
One-dimensional light amplification in individual p-sexiphenyl nanofibers is investigated. The influence of fiber morphology on light propagation properties is studied via optical and atomic force microscopy. Isolated nanofibers are shown to yield low-threshold random laser emission in the deep blue. Model calculations of coherent light propagation in one-dimensional random media qualitatively reproduce the experimental results. Implications for photonic nanosensors are briefly discussed.
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Affiliation(s)
- Francesco Quochi
- Dipartimento di Fisica, Università di Cagliari, I-09042 Monserrato (CA), Italy.
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32
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Artizzu F, Deplano P, Marchiò L, Mercuri ML, Pilia L, Serpe A, Quochi F, Orrù R, Mura A, Bongiovanni G. Structure and emission properties of erbium quinolinolate complexes. Acta Crystallogr A 2005. [DOI: 10.1107/s010876730508503x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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33
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Artizzu F, Deplano P, Marchiò L, Mercuri ML, Pilia L, Serpe A, Quochi F, Orrù R, Cordella F, Meinardi F, Tubino R, Mura A, Bongiovanni G. Structure and Emission Properties of Er3Q9 (Q = 8-Quinolinolate). Inorg Chem 2005; 44:840-2. [PMID: 15859258 DOI: 10.1021/ic0483895] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the first combined optical and structural investigation of the water free Er-quinolinolate complex, an organo-lanthanide system of interest for 1.5-microm telecom applications. Structural data demonstrate that the complex has a trinuclear structure (Er3Q9) which provides the Er metals with an octa-coordination by the organic ligand and prevents solvent and water molecules from entering the lanthanide coordination sphere. The results of the structural analysis allow us to infer that the strong Er luminescence quenching exhibited by the Er3Q9 complex is due uniquely to resonant energy transfer to the aromatic C-H vibrations of the ligand, providing the correct tools to design more efficient emitters.
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Affiliation(s)
- Flavia Artizzu
- Dipartimento di Chimica Inorganica ed Analitica, Università di Cagliari, Cittadella di Monserrato, I-09042 Monserrato, Cagliari, Italy
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34
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Andreev A, Quochi F, Kadashchuk A, Sitter H, Winder C, Hoppe H, Sariciftci S, Mura A, Bongiovanni G. Blue emitting self-assembled nano-fibers of para-sexiphenyl grown by hot wall epitaxy. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pssa.200404810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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35
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Kang I, Dorrer C, Quochi F. Implementation of electro-optic spectral shearing interferometry for ultrashort pulse characterization. Opt Lett 2003; 28:2264-2266. [PMID: 14649962 DOI: 10.1364/ol.28.002264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Electro-optic spectral shearing interferometry is implemented for the highly sensitive characterization of ultrashort pulses from a free-running source. A simple phase-locked-loop clock recovery circuit is used to extract the high-frequency microwave clock signal to drive the phase modulator for spectral shearing. We demonstrate accurate full temporal characterization of 200-fs pulses from an optical parametric oscillator at 5-pW average power.
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Affiliation(s)
- Inuk Kang
- Bell Laboratories-Lucent Technologies, 101 Crawfords Corner Road, Holmdel, New Jersey 07733, USA.
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36
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Saba M, Quochi F, Ciuti C, Oesterle U, Staehli JL, Deveaud B, Bongiovanni G, Mura A. Crossover from exciton to biexciton polaritons in semiconductor microcavities. Phys Rev Lett 2000; 85:385-388. [PMID: 10991289 DOI: 10.1103/physrevlett.85.385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/1999] [Indexed: 05/23/2023]
Abstract
Pump-probe measurements in a microcavity containing a quantum well show that a population of circularly polarized ( sigma(+)) excitons can completely inhibit the transition to sigma(-) one-exciton states by transferring the oscillator strength to the biexcitonic resonance. With increasing pump intensity the linear exciton-polariton doublet evolves into a triplet polariton structure and finally into a shifted biexciton-polariton doublet. A theoretical model of interacting excitons demonstrates that the crossover from exciton to biexciton polaritons is driven by three-exciton Coulomb correlation.
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Affiliation(s)
- M Saba
- Physics Department, Federal Institute of Technology, PH-Ecublens, CH-1015 Lausanne, Switzerland
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37
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Quochi F, Bongiovanni G, Mura A, Staehli JL, Stanley RP, Oesterle U, Houdré R. Optical Stark Effect and Coherent Gain of Excitons in a Semiconductor Microcavity. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/1521-396x(199711)164:1<23::aid-pssa23>3.0.co;2-n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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38
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Buffa G, Carocci S, Minguzzi P, Quochi F, Tarrini O, Tonelli M. Speed Dependence of Pressure Broadening in Molecular Rotational Spectra Using a Novel Technique. Phys Rev Lett 1995; 74:3356-3359. [PMID: 10058180 DOI: 10.1103/physrevlett.74.3356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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