1
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Gupta A, Ondry JC, Chen M, Hudson MH, Coropceanu I, Sarma NA, Talapin DV. Diffusion-Limited Kinetics of Isovalent Cation Exchange in III-V Nanocrystals Dispersed in Molten Salt Reaction Media. NANO LETTERS 2022; 22:6545-6552. [PMID: 35952655 PMCID: PMC9413424 DOI: 10.1021/acs.nanolett.2c01699] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 08/06/2022] [Indexed: 06/15/2023]
Abstract
The goal of this work is to determine the kinetic factors that govern isovalent cation exchange in III-V colloidal quantum dots using molten salts as the solvent and cation source. We focus on the reactions of InP + GaI3→ In1-xGaxP and InAs + GaI3→ In1-xGaxAs to create technologically important ternary III-V phases. We find that the molten salt reaction medium causes the transformation of nearly spherical InP nanocrystals to tetrahedron-shaped In1-xGaxP nanocrystals. Furthermore, we determine that the activation energy for the cation exchange reaction is 0.9 eV for incorporation of Ga into InP and 1.2 eV for incorporation of Ga into InAs, both much lower than the measured values in bulk semiconductors. Next, we use powder XRD simulations to constrain our understanding of the structure of the In1-xGaxP nanocrystals. Together our results reveal several important features of molten salt-mediated cation exchange and provide guidance for future development of these materials.
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Affiliation(s)
- Aritrajit Gupta
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Justin C. Ondry
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Min Chen
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Margaret H. Hudson
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Igor Coropceanu
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Nivedina A. Sarma
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Dmitri V. Talapin
- Department
of Chemistry, James Franck Institute, and Pritzker School of Molecular
Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Center
for Nanoscale Materials, Argonne National
Laboratory, Argonne, Illinois 60439, United
States
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2
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Grüne J, Dyakonov V, Sperlich A. Detecting triplet states in opto-electronic and photovoltaic materials and devices by transient optically detected magnetic resonance. MATERIALS HORIZONS 2021; 8:2569-2575. [PMID: 34870298 DOI: 10.1039/d1mh00999k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Triplet excited states in organic semiconductor materials and devices are notoriously difficult to detect and study with established spectroscopic methods. Yet, they are a crucial intermediate step in next-generation organic light emitting diodes (OLED) that employ thermally activated delayed fluorescence (TADF) to upconvert non-emissive triplets to emissive singlet states. In organic photovoltaic (OPV) devices, however, triplets are an efficiency-limiting exciton loss channel and are also involved in device degradation. Here, we introduce an innovative spin-sensitive method to study triplet states in both, optically excited organic semiconductor films, as well as in electrically driven devices. The method of transient optically detected magnetic resonance (trODMR) can be applied to all light-emitting materials whose luminescence depends on paramagnetic spin states. It is thus an ideal spectroscopic tool to distinguish different states involved and determine their corresponding time scales. We unravel the role of intermediate excited spin states in opto-electronic and photovoltaic materials and devices and reveal fundamental differences in electrically and optically induced triplet states.
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Affiliation(s)
- Jeannine Grüne
- Experimental Physics 6, Julius Maximilian University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Vladimir Dyakonov
- Experimental Physics 6, Julius Maximilian University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Andreas Sperlich
- Experimental Physics 6, Julius Maximilian University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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3
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Rodosthenous P, Gómez-Campos FM, Califano M. Tuning the Radiative Lifetime in InP Colloidal Quantum Dots by Controlling the Surface Stoichiometry. J Phys Chem Lett 2020; 11:10124-10130. [PMID: 33191752 DOI: 10.1021/acs.jpclett.0c02752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
InP nanocrystals exhibit a low photoluminescence quantum yield. As in the case of CdS, this is commonly attributed to their poor surface quality and difficult passivation, which give rise to trap states and negatively affect emission. Hence, the strategies adopted to improve their quantum yield have focused on the growth of shells, to improve passivation and get rid of the surface states. Here, we employ state-of-the-art atomistic semiempirical pseudopotential modeling to isolate the effect of surface stoichiometry from features due to the presence of surface trap states and show that, even with an atomistically perfect surface and an ideal passivation, InP nanostructures may still exhibit very long radiative lifetimes (on the order of tens of microseconds), broad and weak emission, and large Stokes' shifts. Furthermore, we find that all these quantities can be varied by orders of magnitude, by simply manipulating the surface composition, and, in particular, the number of surface P atoms. As a consequence it should be possible to substantially increase the quantum yield in these nanostructures by controlling their surface stoichiometry.
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Affiliation(s)
- Panagiotis Rodosthenous
- Pollard Institute, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Francisco M Gómez-Campos
- Departamento de Electrónica y Tecnología de Computadores, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
- CITIC-UGR, C/Periodista Rafael Gómez Montero, n 2, Granada E-18071, Spain
| | - Marco Califano
- Pollard Institute, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
- Bragg Centre for Materials Research, University of Leeds, Leeds LS2 9JT, United Kingdom
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4
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Tolmachev DO, Ivanov VY, Yakovlev DR, Shornikova EV, Witkowski B, Shendre S, Isik F, Delikani S, Demir HV, Bayer M. Optically detected magnetic resonance in CdSe/CdMnS nanoplatelets. NANOSCALE 2020; 12:21932-21939. [PMID: 33112343 DOI: 10.1039/d0nr05633b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Core/shell CdSe/(Cd,Mn)S colloidal nanoplatelets containing magnetic Mn2+ ions are investigated by the optically detected magnetic resonance technique, combining 60 GHz microwave excitation and photoluminescence detection. Resonant heating of the Mn spin system is observed. We identify two mechanisms of optical detection, via variation of either the photoluminescence polarization or its intensity in an external magnetic field. The spin-lattice relaxation dynamics of the Mn spin system is measured and used for evaluation of the Mn concentration. In CdSe/(Cd,Zn,Mn)S nanoplatelets the addition of Zn in the shells significantly broadens the magnetic resonance, evidencing local strain.
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Affiliation(s)
- Danil O Tolmachev
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany.
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5
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Dehnel J, Barak Y, Meir I, Budniak AK, Nagvenkar AP, Gamelin DR, Lifshitz E. Insight into the Spin Properties in Undoped and Mn-Doped CdSe/CdS-Seeded Nanorods by Optically Detected Magnetic Resonance. ACS NANO 2020; 14:13478-13490. [PMID: 32935976 DOI: 10.1021/acsnano.0c05454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Controlling the spin degrees of freedom of photogenerated species in semiconductor nanostructures via magnetic doping is an emerging scientific field that may play an important role in the development of new spin-based technologies. The current work explores spin properties in colloidal CdSe/CdS:Mn seeded-nanorod structures doped with a dilute concentration of Mn2+ ions across the rods. The spin properties were determined using continuous-wave optically detected magnetic resonance (ODMR) spectroscopy recorded under variable microwave chopping frequencies. These experiments enabled the deconvolution of a few different radiative recombination processes: band-to-band, trap-to-band, and trap-to-trap emission. The results uncovered the major role of carrier trapping on the spin properties of elongated structures. The magnetic parameters, determined through spin-Hamiltonian simulation of the steady-state ODMR spectra, reflect anisotropy associated with carrier trapping at the seed/rod interface. These observations unveiled changes in the carriers' g-factors and spin-exchange coupling constants as well as extension of radiative and spin-lattice relaxation times due to magnetic coupling between interface carriers and neighboring Mn2+ ions. Overall, this work highlights that the spin degrees of freedom in seeded nanorods are governed by interfacial trapping and can be further manipulated by magnetic doping. These results provide insights into anisotropic nanostructure spin properties relevant to future spin-based technologies.
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Affiliation(s)
- Joanna Dehnel
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Itay Meir
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Adam K Budniak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Anjani P Nagvenkar
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Daniel R Gamelin
- Department of Chemistry and the Molecular Engineering Materials Center, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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6
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Hughes KE, Stein JL, Friedfeld MR, Cossairt BM, Gamelin DR. Effects of Surface Chemistry on the Photophysics of Colloidal InP Nanocrystals. ACS NANO 2019; 13:14198-14207. [PMID: 31730352 DOI: 10.1021/acsnano.9b07027] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Indium phosphide (InP) semiconductor nanocrystals (NCs) provide a promising alternative to traditional heavy-metal-based luminescent materials for lighting and display technologies, and implementation of InP NCs in consumer products is rapidly increasing. As-synthesized InP NCs typically have very low photoluminescence quantum yields (PLQY), however. Although empirical methods have led to NCs with near-unity PLQYs, a fundamental understanding of how specific synthetic and post-synthetic protocols can alter the electronic landscape of InP NCs is still lacking. Here, we have studied a series of homologous InP NCs prepared from InP clusters using a combination of room-temperature and low-temperature time-resolved spectroscopies to elucidate how specific charge-carrier trapping processes are affected when various surface modifications are performed. The data allow identification of large PLQY increases that occur specifically through elimination of surface electron traps and provide a rationale for understanding the microscopic origins of this trap suppression in terms of elimination of undercoordinated surface In3+ ions. Despite essentially complete elimination of surface electron trapping when surface In3+ is addressed, hole trapping still exists. This hole trapping is shown to be partially suppressed by even very thin shell growth, attributable to elimination of undercoordinated surface phosphides. We also observe signatures of bright-dark excitonic splitting in InP NCs with only submonolayer surface coverage of select additives (divalent Lewis acids or fluoride anions)-signatures that have only been previously observed in thick-shelled InP NCs. Together, these synthetic and spectroscopic results improve our understanding of relationships between specific InP NC surface chemistries and the resulting NC photophysics.
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Affiliation(s)
- Kira E Hughes
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Jennifer L Stein
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Max R Friedfeld
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Brandi M Cossairt
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
| | - Daniel R Gamelin
- Department of Chemistry , University of Washington , Seattle , Washington 98195-1700 , United States
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7
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Strassberg R, Delikanli S, Barak Y, Dehnel J, Kostadinov A, Maikov G, Hernandez-Martinez PL, Sharma M, Demir HV, Lifshitz E. Persuasive Evidence for Electron-Nuclear Coupling in Diluted Magnetic Colloidal Nanoplatelets Using Optically Detected Magnetic Resonance Spectroscopy. J Phys Chem Lett 2019; 10:4437-4447. [PMID: 31314537 DOI: 10.1021/acs.jpclett.9b01999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The incorporation of magnetic impurities into semiconductor nanocrystals with size confinement promotes enhanced spin exchange interaction between photogenerated carriers and the guest spins. This interaction stimulates new magneto-optical properties with significant advantages for emerging spin-based technologies. Here we observe and elaborate on carrier-guest interactions in magnetically doped colloidal nanoplatelets with the chemical formula CdSe/Cd1-xMnxS, explored by optically detected magnetic resonance and magneto-photoluminescence spectroscopy. The host matrix, with a quasi-type II electronic configuration, introduces a dominant interaction between a photogenerated electron and a magnetic dopant. Furthermore, the data convincingly presents the interaction between an electron and nuclear spins of the doped ions located at neighboring surroundings, with consequent influence on the carrier's spin relaxation time. The nuclear spin contribution by the magnetic dopants in colloidal nanoplatelets is considered here for the first time.
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Affiliation(s)
- Rotem Strassberg
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Savas Delikanli
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology , Bilkent University , Ankara 06800 , Turkey
| | - Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Joanna Dehnel
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Alyssa Kostadinov
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Georgy Maikov
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Pedro Ludwig Hernandez-Martinez
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
| | - Manoj Sharma
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology , Bilkent University , Ankara 06800 , Turkey
| | - Hilmi Volkan Demir
- Luminous Center of Excellence for Semiconductor Lighting and Displays, TPI, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering , Nanyang Technological University-NTU Singapore , 639798 Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology , Bilkent University , Ankara 06800 , Turkey
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute , Technion-Israel Institute of Technology , Haifa 32000 , Israel
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8
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Janke EM, Williams NE, She C, Zherebetskyy D, Hudson MH, Wang L, Gosztola DJ, Schaller RD, Lee B, Sun C, Engel GS, Talapin DV. Origin of Broad Emission Spectra in InP Quantum Dots: Contributions from Structural and Electronic Disorder. J Am Chem Soc 2018; 140:15791-15803. [DOI: 10.1021/jacs.8b08753] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eric M. Janke
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Nicholas E. Williams
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Chunxing She
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Danylo Zherebetskyy
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Margaret H. Hudson
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Lili Wang
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - David J. Gosztola
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Richard D. Schaller
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Byeongdu Lee
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Chengjun Sun
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Gregory S. Engel
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Dmitri V. Talapin
- Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
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9
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Lifshitz E. Evidence in Support of Exciton to Ligand Vibrational Coupling in Colloidal Quantum Dots. J Phys Chem Lett 2015; 6:4336-4347. [PMID: 26538048 DOI: 10.1021/acs.jpclett.5b01567] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Perspective focuses on the investigation of an unresolved conflict in semiconductor colloidal quantum dots (CQDs) research, concerning the influence of the immediate surrounding on the optical properties of the materials. Today's advanced synthetic colloidal procedures offer formation of a high-quality inorganic crystallite, capped with various organic/inorganic molecular ligands. The Perspective aims to clarify whether exciton recombination processes in CQDs are influenced by the type of crystallite-ligand bonding and, moreover, whether these excitonic processes experience direct coupling to the ligands' vibrational modes. Most ligands used have redox characteristics whose functional groups are added on to the CQDs' surface via coordination, covalent or ionic bonding. The surface-ligand bonding introduces electronic states either above or below the intraband/interband energy gap, resulting in electronic passivation or in creation of trapping states that affect intraband and interband relaxation processes. Furthermore, crystalline electronic states may have a direct coupling to molecular vibrational states via direct overlap of electronic wave functions or through a long-range energy-transfer process. Also, photoejected carriers resulting from an Auger process or ionization processes may diffuse temporarily onto a ligand site. These scenarios are discussed in the current publication with supporting theoretical and experimental observations.
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Affiliation(s)
- Efrat Lifshitz
- Schulich Faculty of Chemistry, Russell Berrie Nanotechnology Institute, Solid State Institute, Technion, Israel Institute of Technology , Haifa 32000, Israel
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10
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Nozik AJ, Beard MC, Luther JM, Law M, Ellingson RJ, Johnson JC. Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells. Chem Rev 2010; 110:6873-90. [PMID: 20945911 DOI: 10.1021/cr900289f] [Citation(s) in RCA: 529] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. J. Nozik
- The National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States, Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, and Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - M. C. Beard
- The National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States, Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, and Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - J. M. Luther
- The National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States, Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, and Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - M. Law
- The National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States, Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, and Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - R. J. Ellingson
- The National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States, Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, and Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - J. C. Johnson
- The National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States, Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, and Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
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11
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Zerzouf O, Haase M. Influence of the Choice of Indium Precursor and Ligand on the Synthesis of InP Nanocrystals. Z PHYS CHEM 2009. [DOI: 10.1524/zpch.2007.221.3.393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Well-crystallized InP nanocrystals with particle diameters ranging from 2 to 5.5nm were prepared via the reaction between tris(trimethylsilyl)phosphine and different indium precursors. The classic TOP/TOPO reaction medium was replaced by the weakly coordinating solvent diphenylether, which contained a strongly coordinating ligand at low concentrations. Different phosphine oxides, phosphines, phosphates, phosphites and phosphonates were used as ligands and their influence on the growth of InP nanocrystals was studied. The synthesis procedure allows to prepare crystalline InP quantum dots (QDs) at temperatures as low as 150°C and within short reaction times. The final size of the InP QDs is remarkably independent of the choice of ligand and indium precursor.
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12
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Dimitrijević NM, Rajh T, Ahrenkiel SP, Nedeljković JM, Mićić OI, Nozik AJ. Charge separation in heterostructures of InP nanocrystals with metal particles. J Phys Chem B 2007; 109:18243-9. [PMID: 16853347 DOI: 10.1021/jp051201y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The optical and electron paramagnetic resonance (EPR) properties of InP nanocrystals, in which metallic gold or indium is present as an incorporated part of the nanocrystals, have been studied. A study of Au/InP quantum rods supports different carrier localization regimes compared to metal-free quantum rods, including the charge-separated state for which the electron and hole are located in different parts of the heterostructure. They also show that elongated semiconductors that grow on metallic catalysts have electronic properties that are different from those of pure semiconductor nanocrystals of the same shape. We have also developed a simple method for growing melted indium particles on the surface of colloidal spherical InP nanocrystals, and in these In/InP nanocrystals the emission is completely quenched while the absorption spectrum moves to red due to the strong mixing of the semiconductor and metal electronic states.
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Affiliation(s)
- Nada M Dimitrijević
- Chemistry Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA
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13
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Rogach AL, Eychmüller A, Hickey SG, Kershaw SV. Infrared-emitting colloidal nanocrystals: synthesis, assembly, spectroscopy, and applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:536-57. [PMID: 17340666 DOI: 10.1002/smll.200600625] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Semiconductor nanocrystals produced by means of colloidal chemistry in a solvent medium are an attractive class of nanometer-sized building blocks from which to create complex materials with unique properties for a variety of applications. Their optical and electronic properties can be tailored easily, both by their chemical composition and particle size. While colloidal nanocrystals emitting in the infrared region have seen a burst of attention during the last decade there is clearly a paucity of review articles covering their synthesis, assembly, spectroscopic characterization, and applications. This Review comprehensively addresses these topics for II-VI, III-V, and IV-VI nanocrystals, examples being HgTe and Cd(x)Hg(1-) (x)Te, InP and InAs, and PbS, PbSe, and PbTe, respectively. Among the applications discussed here are optical amplifier media for telecommunications systems, electroluminescence devices, and noninvasive optical imaging in biology.
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Affiliation(s)
- Andrey L Rogach
- Photonics and Optoelectronics Group, Physics Department and Centre for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Munich, Germany.
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14
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Scholes GD. Selection rules for probing biexcitons and electron spin transitions in isotropic quantum dot ensembles. J Chem Phys 2006; 121:10104-10. [PMID: 15549885 DOI: 10.1063/1.1808414] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Three-dimensional rotational averages are evaluated for third-order nonlinear spectroscopic measurements of quantum dots. Photon echo, transient grating, and transient absorption are explicitly considered. It is shown that (a) biexciton formation can be suppressed relative to other contributions to nonlinear spectroscopies for isotropic nanocrystal ensembles by choice of polarizations for the excitation pulses; (b) circularly polarized excitation light can differentiate between exciton spin states in nonlinear optical experiments; and (c) electron spin state flip kinetics can be probed directly in an isotropic quantum dot system by using certain sequences of linear cross-polarized pulses.
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Affiliation(s)
- Gregory D Scholes
- Lash-Miller Chemical Laboratories, 80 St. George Street, University of Toronto, Toronto, Ontario, M5S 3H6 Canada
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15
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Pazy E. Spin-Based Optical Quantum Information Processing. Isr J Chem 2006. [DOI: 10.1560/ijc_46_4_357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Nozik AJ. Autobiography and Scientific History of Arthur J. Nozik. J Phys Chem B 2006; 110:25126-32. [PMID: 17165953 DOI: 10.1021/jp0680948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Adam S, Talapin DV, Borchert H, Lobo A, McGinley C, de Castro ARB, Haase M, Weller H, Möller T. The effect of nanocrystal surface structure on the luminescence properties: Photoemission study of HF-etched InP nanocrystals. J Chem Phys 2005; 123:084706. [PMID: 16164320 DOI: 10.1063/1.2004901] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
InP nanocrystals with narrow size distribution and mean particle diameter tunable from approximately 2 up to approximately 7 nm were synthesized via the dehalosilylation reaction between InCl3 and tris(trimethylsilyl)phosphine. Specific capping of the nanocrystal surface with a shell of organic ligands protects the nanocrystals from oxidation and provides solubility of the particles in various organic solvents. InP nanocrystals with enhanced photoluminescence (PL) efficiency were obtained from the initial nanocrystals by photoassisted etching of the nanocrystal surface with HF. The resulting PL quantum efficiency of InP nanocrystals dispersed in n-butanol is about three orders of magnitude higher when compared to the nonetched InP samples and approaches approximately 40% at room temperature. High-resolution photoelectron spectroscopy with the use of synchrotron radiation was applied to reveal the changes of the nanocrystal surface responsible for the dramatic improvement of the PL efficiency. The analysis of high-resolution P 2p core-level spectra confirmed significant changes of the nanocrystal surface structure induced by the postpreparative treatments and allowed us to propose the description of the etching mechanism. In the nonetched InP nanocrystals, some surface P atoms generate energy states located inside the band gap which provide nonradiative recombination pathways. Photoassisted treatment of InP nanocrystals with HF results in selective removal of these phosphorous atoms from the nanocrystal surface. The reconstructed surface of the etched InP nanocrystals is terminated mainly with In atoms and is efficiently passivated with tri-n-octylphosphine oxide ligands.
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Affiliation(s)
- S Adam
- HASYLAB/DESY Notkestrasse 85, 22603 Hamburg, Germany
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Bharali DJ, Lucey DW, Jayakumar H, Pudavar HE, Prasad PN. Folate-Receptor-Mediated Delivery of InP Quantum Dots for Bioimaging Using Confocal and Two-Photon Microscopy. J Am Chem Soc 2005; 127:11364-71. [PMID: 16089466 DOI: 10.1021/ja051455x] [Citation(s) in RCA: 287] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel method for the synthesis of highly monodispersed hydrophillic InP-ZnS nanocrystals and their use as luminescence probes for live cell imaging is reported. Hydrophobic InP-ZnS nanocrystals are prepared by a new method that yields high-quality, luminescent core-shell nanocrystals within 6-8 h of total reaction time. Then by carefully manipulating the surface of these passivated nanocrystals, aqueous dispersions of folate-conjugated nanocrystals (folate-QDs) with high photostability are prepared. By use of confocal microscopy, we demonstrate the receptor-mediated delivery of folic acid conjugated quantum dots into folate-receptor-positive cell lines such as KB cells. These folate-QDs tend to accumulate in multi-vescicular bodies of KB cells after 6 h of incubation. Receptor-mediated delivery was confirmed by comparison with the uptake of these particles in folate-receptor-negative cell lines such as A549. Efficient two-photon excitation of these particles and two-photon imaging using these particles are also demonstrated. The use of these InP-ZnS nanoparticles and their efficient two-photon excitation can be potentially useful for deep tissue imaging for future in vivo studies.
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Affiliation(s)
- Dhruba J Bharali
- Institute for Laser, Photonics and Biophotonics, and Department of Chemistry, The University of Buffalo, Buffalo, New York 14260-3000, USA
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Lifshitz E, Fradkin L, Glozman A, Langof L. OPTICALLY DETECTED MAGNETIC RESONANCE STUDIES OF COLLOIDAL SEMICONDUCTOR NANOCRYSTALS. Annu Rev Phys Chem 2004; 55:509-57. [PMID: 15117261 DOI: 10.1146/annurev.physchem.55.091602.094359] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The review describes the studies of the magneto-optical properties of II-VI and III-V semiconductor nanocrystals (NCs) capped with organic or inorganic epitaxial shells. The investigations focused on the chemical identification of localization sites (core, shell, or interface) of photogenerated carriers in spherical NCs and elucidated the influence of the surface/interface quality on the optical properties of the materials. Optically detected magnetic resonance (ODMR) spectroscopy was used for the study of the proposed physical properties. The ODMR method provides the means to identify the surface/interface sites and correlate them with specific optical transition. In addition, this method reveals information about the spin multiplicity of band edge and trapped states and the electron-hole exchange interaction, determines the spectroscopic g-factors, distinguishes between the radiative and nonradiative characteristic of a trapping site, and evaluates the spin-lattice relaxation times.
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Affiliation(s)
- E Lifshitz
- Department of Chemistry and Solid State Institute, Technion, Haifa 32000, Israel.
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Colloidal InP/ZnS core–shell nanocrystals studied by linearly and circularly polarized photoluminescence. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2003.10.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Fradkin L, Langof L, Lifshitz E, Rogach A, Gaponik N, Weller H, Eychmüller A. Magneto-Optical Studies of HgTe/HgxCd1−xTe(S) Core-Shell Nanocrystals. Chemphyschem 2003; 4:1203-10. [PMID: 14652999 DOI: 10.1002/cphc.200300809] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The synthesis and magneto-optical properties of HgTe nanocrystals capped with HgxCd1-xTe(S) alloyed shells have been investigated. The magneto-optical measurements included the use of optically detected magnetic resonance (ODMR) and circular polarized photoluminescence (CP-PL) spectroscopy. The PL spectra suggest the existence of luminescence events from both the core HgTe and the HgxCd1-xTe(S) shells. The continuous-wave (cw) and time-resolved ODMR measurements revealed that the luminescence at the shell regime is associated with a trap-to-band recombination emission. The electron trap is comprised of a Cd-Hg mixed site, confirming the existence of an alloyed HgxCd1-xTe(S) composition. The ODMR data and the CP-PL measurements together revealed the g-values of the trapped electron and the valence band hole.
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Affiliation(s)
- Leonid Fradkin
- Department of Chemistry and Solid State Institute, Technion-Israel Institute of Technology, 32000 Haifa, Israel
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Lou Y, Chen X, Samia AC, Burda C. Femtosecond Spectroscopic Investigation of the Carrier Lifetimes in Digenite Quantum Dots and Discrimination of the Electron and Hole Dynamics via Ultrafast Interfacial Electron Transfer. J Phys Chem B 2003. [DOI: 10.1021/jp035618k] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Yongbing Lou
- Center for Chemical Dynamics and Nanomaterials Research, Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Xiaobo Chen
- Center for Chemical Dynamics and Nanomaterials Research, Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Anna C. Samia
- Center for Chemical Dynamics and Nanomaterials Research, Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
| | - Clemens Burda
- Center for Chemical Dynamics and Nanomaterials Research, Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106
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Tu H, Chikan V, Kelley DF. Electron and Hole Intraband Spectroscopy of GaSe Nanoparticles. J Phys Chem B 2003. [DOI: 10.1021/jp034297+] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Blackburn JL, Ellingson RJ, Mićić OI, Nozik AJ. Electron Relaxation in Colloidal InP Quantum Dots with Photogenerated Excitons or Chemically Injected Electrons. J Phys Chem B 2002. [DOI: 10.1021/jp026746w] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeff L. Blackburn
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
| | - Randy J. Ellingson
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
| | - Olga I. Mićić
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
| | - Arthur J. Nozik
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
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Mićić OI, Nozik AJ, Lifshitz E, Rajh T, Poluektov OG, Thurnauer MC. Electron and Hole Adducts Formed in Illuminated InP Colloidal Quantum Dots Studied by Electron Paramagnetic Resonance. J Phys Chem B 2002. [DOI: 10.1021/jp014180q] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Efrat Lifshitz
- Solid State Institute, TechnionIsrael Institute of Technology, Haifa 32000, Israel
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