1
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Gross N, Kuhs CT, Ostovar B, Chiang WY, Wilson KS, Volek TS, Faitz ZM, Carlin CC, Dionne JA, Zanni MT, Gruebele M, Roberts ST, Link S, Landes CF. Progress and Prospects in Optical Ultrafast Microscopy in the Visible Spectral Region: Transient Absorption and Two-Dimensional Microscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:14557-14586. [PMID: 37554548 PMCID: PMC10406104 DOI: 10.1021/acs.jpcc.3c02091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/24/2023] [Indexed: 08/10/2023]
Abstract
Ultrafast optical microscopy, generally employed by incorporating ultrafast laser pulses into microscopes, can provide spatially resolved mechanistic insight into scientific problems ranging from hot carrier dynamics to biological imaging. This Review discusses the progress in different ultrafast microscopy techniques, with a focus on transient absorption and two-dimensional microscopy. We review the underlying principles of these techniques and discuss their respective advantages and applicability to different scientific questions. We also examine in detail how instrument parameters such as sensitivity, laser power, and temporal and spatial resolution must be addressed. Finally, we comment on future developments and emerging opportunities in the field of ultrafast microscopy.
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Affiliation(s)
- Niklas Gross
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Christopher T. Kuhs
- Army
Research Laboratory-South, U.S. Army DEVCOM, Houston, Texas 77005, United States
| | - Behnaz Ostovar
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Wei-Yi Chiang
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Kelly S. Wilson
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Tanner S. Volek
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Zachary M. Faitz
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Claire C. Carlin
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Jennifer A. Dionne
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
- Department
of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford, California 94305, United States
| | - Martin T. Zanni
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Martin Gruebele
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, Illinois 61801, United States
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Center
for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Sean T. Roberts
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Stephan Link
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Christy F. Landes
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
- Department
of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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2
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Zhu Y, Cheng JX. Transient absorption microscopy: Technological innovations and applications in materials science and life science. J Chem Phys 2020; 152:020901. [PMID: 31941290 PMCID: PMC7195865 DOI: 10.1063/1.5129123] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/15/2019] [Indexed: 01/08/2023] Open
Abstract
Transient absorption (TA) spectroscopy has been extensively used in the study of excited state dynamics of various materials and molecules. The transition from TA spectroscopy to TA microscopy, which enables the space-resolved measurement of TA, is opening new investigations toward a more complete picture of excited state dynamics in functional materials, as well as the mapping of crucial biopigments for precision diagnosis. Here, we review the recent instrumental advancement that is pushing the limit of spatial resolution, detection sensitivity, and imaging speed. We further highlight the emerging application in materials science and life science.
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Affiliation(s)
- Yifan Zhu
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
| | - Ji-Xin Cheng
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
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3
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Zhu T, Snaider JM, Yuan L, Huang L. Ultrafast Dynamic Microscopy of Carrier and Exciton Transport. Annu Rev Phys Chem 2019; 70:219-244. [PMID: 30883273 DOI: 10.1146/annurev-physchem-042018-052605] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We highlight the recent progress in ultrafast dynamic microscopy that combines ultrafast optical spectroscopy with microscopy approaches, focusing on the application transient absorption microscopy (TAM) to directly image energy and charge transport in solar energy harvesting and conversion systems. We discuss the principles, instrumentation, and resolutions of TAM. The simultaneous spatial, temporal, and excited-state-specific resolutions of TAM unraveled exciton and charge transport mechanisms that were previously obscured in conventional ultrafast spectroscopy measurements for systems such as organic solar cells, hybrid perovskite thin films, and molecular aggregates. We also discuss future directions to improve resolutions and to develop other ultrafast imaging contrasts beyond transient absorption.
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Affiliation(s)
- Tong Zhu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
- Laser/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Jordan M. Snaider
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Long Yuan
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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4
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Schröder FAYN, Turban DHP, Musser AJ, Hine NDM, Chin AW. Tensor network simulation of multi-environmental open quantum dynamics via machine learning and entanglement renormalisation. Nat Commun 2019; 10:1062. [PMID: 30837477 PMCID: PMC6401190 DOI: 10.1038/s41467-019-09039-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 02/05/2019] [Indexed: 02/06/2023] Open
Abstract
The simulation of open quantum dynamics is a critical tool for understanding how the non-classical properties of matter might be functionalised in future devices. However, unlocking the enormous potential of molecular quantum processes is highly challenging due to the very strong and non-Markovian coupling of 'environmental' molecular vibrations to the electronic 'system' degrees of freedom. Here, we present an advanced but general computational strategy that allows tensor network methods to effectively compute the non-perturbative, real-time dynamics of exponentially large vibronic wave functions of real molecules. We demonstrate how ab initio modelling, machine learning and entanglement analysis can enable simulations which provide real-time insight and direct visualisation of dissipative photophysics, and illustrate this with an example based on the ultrafast process known as singlet fission.
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Affiliation(s)
- Florian A Y N Schröder
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK
| | - David H P Turban
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Andrew J Musser
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK
| | - Nicholas D M Hine
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Alex W Chin
- CNRS & Institut des NanoSciences de Paris, Sorbonne Université, 4 place Jussieu, boite courrier 840, 75252 PARIS, Cedex 05, France.
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5
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Beane G, Devkota T, Brown BS, Hartland GV. Ultrafast measurements of the dynamics of single nanostructures: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:016401. [PMID: 30485256 DOI: 10.1088/1361-6633/aaea4b] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The ability to study single particles has revolutionized nanoscience. The advantage of single particle spectroscopy measurements compared to conventional ensemble studies is that they remove averaging effects from the different sizes and shapes that are present in the samples. In time-resolved experiments this is important for unraveling homogeneous and inhomogeneous broadening effects in lifetime measurements. In this report, recent progress in the development of ultrafast time-resolved spectroscopic techniques for interrogating single nanostructures will be discussed. The techniques include far-field experiments that utilize high numerical aperture (NA) microscope objectives, near-field scanning optical microscopy (NSOM) measurements, ultrafast electron microscopy (UEM), and time-resolved x-ray diffraction experiments. Examples will be given of the application of these techniques to studying energy relaxation processes in nanoparticles, and the motion of plasmons, excitons and/or charge carriers in different types of nanostructures.
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Affiliation(s)
- Gary Beane
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, United States of America
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6
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Wang F, Dong A, Buhro WE. Solution–Liquid–Solid Synthesis, Properties, and Applications of One-Dimensional Colloidal Semiconductor Nanorods and Nanowires. Chem Rev 2016; 116:10888-933. [DOI: 10.1021/acs.chemrev.5b00701] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fudong Wang
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130-4899, United States
| | - Angang Dong
- Collaborative
Innovation Center of Chemistry for Energy Materials, Shanghai Key
Laboratory of Molecular Catalysis and Innovative Materials, and Department
of Chemistry, Fudan University, Shanghai 200433, China
| | - William E. Buhro
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130-4899, United States
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7
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Fischer MC, Wilson JW, Robles FE, Warren WS. Invited Review Article: Pump-probe microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:031101. [PMID: 27036751 PMCID: PMC4798998 DOI: 10.1063/1.4943211] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 02/07/2016] [Indexed: 05/17/2023]
Abstract
Multiphoton microscopy has rapidly gained popularity in biomedical imaging and materials science because of its ability to provide three-dimensional images at high spatial and temporal resolution even in optically scattering environments. Currently the majority of commercial and home-built devices are based on two-photon fluorescence and harmonic generation contrast. These two contrast mechanisms are relatively easy to measure but can access only a limited range of endogenous targets. Recent developments in fast laser pulse generation, pulse shaping, and detection technology have made accessible a wide range of optical contrasts that utilize multiple pulses of different colors. Molecular excitation with multiple pulses offers a large number of adjustable parameters. For example, in two-pulse pump-probe microscopy, one can vary the wavelength of each excitation pulse, the detection wavelength, the timing between the excitation pulses, and the detection gating window after excitation. Such a large parameter space can provide much greater molecular specificity than existing single-color techniques and allow for structural and functional imaging without the need for exogenous dyes and labels, which might interfere with the system under study. In this review, we provide a tutorial overview, covering principles of pump-probe microscopy and experimental setup, challenges associated with signal detection and data processing, and an overview of applications.
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Affiliation(s)
- Martin C Fischer
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jesse W Wilson
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Francisco E Robles
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Warren S Warren
- Departments of Chemistry, Biomedical Engineering, Physics, and Radiology, Duke University, Durham, North Carolina 27708, USA
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8
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Zhang W, Lehmann S, Mergenthaler K, Wallentin J, Borgström MT, Pistol ME, Yartsev A. Carrier Recombination Dynamics in Sulfur-Doped InP Nanowires. NANO LETTERS 2015; 15:7238-44. [PMID: 26421505 DOI: 10.1021/acs.nanolett.5b02022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Measuring lifetime of photogenerated charges in semiconductor nanowires (NW) is important for understanding light-induced processes in these materials and is relevant for their photovoltaic and photodetector applications. In this paper, we investigate the dynamics of photogenerated charge carriers in a series of as-grown InP NW with different levels of sulfur (S) doping. We observe that photoluminescence (PL) decay time as well as integrated PL intensity decreases with increasing S doping. We attribute these observations to hole trapping with the trap density increased due to S-doping level followed by nonradiative recombination of trapped charges. This assignment is proven by observation of the trap saturation in three independent experiments: via excitation power and repetition rate PL lifetime dependencies and by PL pump-probe experiment.
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Affiliation(s)
- Wei Zhang
- Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Sebastian Lehmann
- Department of Solid State Physics, Lund University , Box 118, 221 00 Lund, Sweden
| | - Kilian Mergenthaler
- Department of Solid State Physics, Lund University , Box 118, 221 00 Lund, Sweden
| | - Jesper Wallentin
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Magnus T Borgström
- Department of Solid State Physics, Lund University , Box 118, 221 00 Lund, Sweden
| | - Mats-Erik Pistol
- Department of Solid State Physics, Lund University , Box 118, 221 00 Lund, Sweden
| | - Arkady Yartsev
- Division of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
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9
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Devadas MS, Devkota T, Johns P, Li Z, Lo SS, Yu K, Huang L, Hartland GV. Imaging nano-objects by linear and nonlinear optical absorption microscopies. NANOTECHNOLOGY 2015; 26:354001. [PMID: 26266335 DOI: 10.1088/0957-4484/26/35/354001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Absorption based microscopy measurements are emerging as important tools for studying nanomaterials. This review discusses the three most common techniques for performing these experiments: transient absorption microscopy, photothermal heterodyne imaging, and spatial modulation spectroscopy. The focus is on the application of these techniques to imaging and detection, using examples taken from the authors' laboratory. The advantages and disadvantages of the three methods are discussed, with an emphasis on the unique information that can be obtained from these experiments, in comparison to conventional emission or scattering based microscopy experiments.
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Affiliation(s)
- Mary Sajini Devadas
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556-5670, USA
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10
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Erhard N, Sarwar ATMG, Yang F, McComb DW, Myers RC, Holleitner AW. Optical control of internal electric fields in band gap-graded InGaN nanowires. NANO LETTERS 2015; 15:332-338. [PMID: 25487601 DOI: 10.1021/nl503616w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
InGaN nanowires are suitable building blocks for many future optoelectronic devices. We show that a linear grading of the indium content along the nanowire axis from GaN to InN introduces an internal electric field evoking a photocurrent. Consistent with quantitative band structure simulations we observe a sign change in the measured photocurrent as a function of photon flux. This negative differential photocurrent opens the path to a new type of nanowire-based photodetector. We demonstrate that the photocurrent response of the nanowires is as fast as 1.5 ps.
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Affiliation(s)
- N Erhard
- Walter Schottky Institut and Physik-Department, Technische Universität München , D-85748 Garching, Germany
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11
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Li Y, Clady R, Park J, Thombare SV, Schmidt TW, Brongersma ML, McIntyre PC. Ultrafast electron and phonon response of oriented and diameter-controlled germanium nanowire arrays. NANO LETTERS 2014; 14:3427-3431. [PMID: 24797453 DOI: 10.1021/nl500953p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Carrier and phonon dynamics in dense arrays of aligned, single-crystal Ge nanowires (NWs) of controlled diameter are investigated by ultrafast optical pump-probe measurements, effective medium calculations, and elasticity analysis. Both a pronounced induced absorption and the amplitude and spectral range of Fabry-Perot oscillations observed in the probe signal are predicted for the NW array/air metamaterial by effective medium calculations. Detected temporal oscillations of reflectivity are consistent with excitation of radial breathing mode acoustic phonons by the intense pump pulse.
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Affiliation(s)
- Yanying Li
- Department of Applied Physics and §Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States
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12
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Major TA, Lo SS, Yu K, Hartland GV. Time-Resolved Studies of the Acoustic Vibrational Modes of Metal and Semiconductor Nano-objects. J Phys Chem Lett 2014; 5:866-874. [PMID: 26274080 DOI: 10.1021/jz4027248] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Over the past decade, there have been a number of transient absorption studies of the acoustic vibrational modes of metal and semiconductor nanoparticles. This Perspective provides an overview of this work. The way that the frequencies of the observed modes depend on the size and shape of the particles is described, along with their damping. Future research directions are also discussed, especially how these measurements provide information about the way nano-objects interact with their environment.
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Affiliation(s)
- Todd A Major
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Shun Shang Lo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Kuai Yu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Gregory V Hartland
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
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13
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Crut A, Maioli P, Del Fatti N, Vallée F. Optical absorption and scattering spectroscopies of single nano-objects. Chem Soc Rev 2014; 43:3921-56. [DOI: 10.1039/c3cs60367a] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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14
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Schumacher T, Giessen H, Lippitz M. Ultrafast spectroscopy of quantum confined states in a single CdSe nanowire. NANO LETTERS 2013; 13:1706-1710. [PMID: 23517464 DOI: 10.1021/nl400259f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We measure for the first time transient absorption spectra of individual CdSe nanowires with about 10 nm diameter. Confinement of the carrier wave functions leads to discrete states which can be described by a six-band effective mass model. Combining transient absorption and luminescence spectroscopy allows us to track the excitation dynamics in the visible and near-infrared spectral range. About 10% of all absorbed photons lead to an excitation of the lowest energy state. Of these excitations, less than 1% lead to a photon in the optical far-field. Almost all emission is reabsorbed by other parts of the nanowire. These findings might explain the low overall quantum efficiency of CdSe nanowires.
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15
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Lo SS, Major TA, Petchsang N, Huang LB, Kuno M, Hartland GV. CdTe Nanowires studied by Transient Absorption Microscopy. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134104032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Lo SS, Devadas MS, Major TA, Hartland GV. Optical detection of single nano-objects by transient absorption microscopy. Analyst 2013; 138:25-31. [DOI: 10.1039/c2an36097g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Xing G, Liao Y, Wu X, Chakrabortty S, Liu X, Yeow EKL, Chan Y, Sum TC. Ultralow-threshold two-photon pumped amplified spontaneous emission and lasing from seeded CdSe/CdS nanorod heterostructures. ACS NANO 2012; 6:10835-10844. [PMID: 23157595 DOI: 10.1021/nn304200a] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ultralow-threshold two-photon pumped amplified spontaneous emission (2ASE) and lasing in seeded CdSe/CdS nanodot/nanorod heterostructures is demonstrated for the first time. Such heterostructures allow the independent tunability of the two-photon absorption (2PA) cross-section (σ(2)) through varying the CdS rod size, and that of the emission wavelength through varying the CdSe dot size. With an enhanced σ(2), 2ASE in these heterostructures is achieved with an ultralow threshold fluence of ~1.5 mJ/cm(2), which is as much as one order less than that required for spherical semiconductor NCs. Importantly, by exploiting this unique property of the seeded nanorods exhibiting strong quantum confinement even at relatively large rod sizes, a near reciprocal relation between the 2ASE threshold and the 2PA action cross-section (σ(2)η) (where η is the quantum yield) was found and validated over a wide volume range for II-VI semiconductor nanostructures. Ultrafast optical spectroscopy verified that while the Auger processes in these heterostructures are indeed suppressed, ASE in these samples could also be strongly affected by a fast hole-trapping process to the NR surface states. Lastly, to exemplify the potential of these seeded CdSe/CdS nanodot/nanorod heterostructures as a viable gain media for achieving two-photon lasing, a highly photostable microsphere laser with an ultralow pump threshold is showcased.
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Affiliation(s)
- Guichuan Xing
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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18
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Seo MA, Yoo J, Dayeh SA, Picraux ST, Taylor AJ, Prasankumar RP. Mapping carrier diffusion in single silicon core-shell nanowires with ultrafast optical microscopy. NANO LETTERS 2012; 12:6334-6338. [PMID: 23130749 DOI: 10.1021/nl303502f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Recent success in the fabrication of axial and radial core-shell heterostructures, composed of one or more layers with different properties, on semiconductor nanowires (NWs) has enabled greater control of NW-based device operation for various applications. (1-3) However, further progress toward significant performance enhancements in a given application is hindered by the limited knowledge of carrier dynamics in these structures. In particular, the strong influence of interfaces between different layers in NWs on transport makes it especially important to understand carrier dynamics in these quasi-one-dimensional systems. Here, we use ultrafast optical microscopy (4) to directly examine carrier relaxation and diffusion in single silicon core-only and Si/SiO(2) core-shell NWs with high temporal and spatial resolution in a noncontact manner. This enables us to reveal strong coherent phonon oscillations and experimentally map electron and hole diffusion currents in individual semiconductor NWs for the first time.
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Affiliation(s)
- M A Seo
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
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