51
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Botas AMP, Anthony RJ, Wu J, Rowe DJ, Silva NJO, Kortshagen U, Pereira RN, Ferreira RAS. Influence of the surface termination on the light emission of crystalline silicon nanoparticles. NANOTECHNOLOGY 2016; 27:325703. [PMID: 27348305 DOI: 10.1088/0957-4484/27/32/325703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The light emission properties of silicon crystalline nanoparticles (SiNPs) have been investigated using steady-state and time-resolved photoluminescence measurements carried out at 12 K and at room temperature. To enable a comparative study of the role of surface terminal groups on the optical properties, we investigated SiNPs-H ensembles with the same mean NP diameter but differing on the surface termination, namely organic-functionalized with 1-dodecene (SiNPs-C12) and H-terminated (SiNPs-H). We show that although the spectral dependence of the light emission is rather unaffected by surface termination, characterized by a single broad band peaking at ∼1.64 eV, both the exciton recombination lifetimes and quantum yields display a pronounced dependence on the surface termination. Exciton lifetimes and quantum yields are found to be significantly lower in SiNPs-H compared SiNPs-C12. This difference is due to distinct non-radiative recombination probabilities resulting from inter-NP exciton migration, which in SiNPs-C12 is inhibited by the energy barriers imposed by the bulky surface groups. The surface groups of organic-terminated SiPs are responsible for the inhibition of inter-NP exciton transfer, yielding a higher quantum yield compared to SiNPs-H. The surface oxidation of SiNPs-C12 leads to the appearance of a phenomenon of an exciton transference from to the Si core to oxide-related states that contribute to light emission. These excitons recombine radiatively, explaining why the emission quantum of the organic-terminated SiNPs is the same after surface oxidation of SiNPs-C12.
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Affiliation(s)
- Alexandre M P Botas
- Department of Physics and CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal. Department of Physics and I3N, University of Aveiro, Aveiro 3810-193, Portugal
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52
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Romano F, Yu Y, Korgel BA, Bergamini G, Ceroni P. Light-Harvesting Antennae Based on Silicon Nanocrystals. Top Curr Chem (Cham) 2016; 374:53. [PMID: 27573405 DOI: 10.1007/s41061-016-0056-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/13/2016] [Indexed: 11/26/2022]
Abstract
Silicon (Si) nanocrystals are relatively strong light emitters, but are weak light absorbers as a result of their indirect band gap. One way to enhance light absorption is to functionalize the nanocrystals with chromophores that are strong light absorbers. By designing systems that enable efficient energy transfer from the chromophore to the Si nanocrystal, the brightness of the nanocrystals can be significantly increased. There have now been a few experimental systems in which covalent attachment of chromophores, efficient energy transfer and significantly increased brightness have been demonstrated. This review discusses progress on these systems and the remaining challenges.
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Affiliation(s)
- Francesco Romano
- Department of Chemistry "G. Ciamician", University of Bologna, Via Selmi 2, 40126, Bologna, Italy
| | - Yixuan Yu
- Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Brian A Korgel
- Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, TX, 78712, USA.
| | - Giacomo Bergamini
- Department of Chemistry "G. Ciamician", University of Bologna, Via Selmi 2, 40126, Bologna, Italy
| | - Paola Ceroni
- Department of Chemistry "G. Ciamician", University of Bologna, Via Selmi 2, 40126, Bologna, Italy.
- Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (SOLAR-CHEM), Unità di Bologna, Bologna, Italy.
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53
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McVey BFP, Prabakar S, Gooding JJ, Tilley RD. Solution Synthesis, Surface Passivation, Optical Properties, Biomedical Applications, and Cytotoxicity of Silicon and Germanium Nanocrystals. Chempluschem 2016; 82:60-73. [DOI: 10.1002/cplu.201600207] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Benjamin F. P. McVey
- School of Chemistry and Electron Microscopy Unit; of the Mark Wainwright Analytical Centre; University of New South Wales; Sydney NSW 2052 Australia
| | - Sujay Prabakar
- Leather&Shoe Research Association of New Zealand; and the MacDiarmid Institute for Advanced Materials and Nanotechnology; Palmerston North 4446 New Zealand
| | - Justin J. Gooding
- School of Chemistry and Electron Microscopy Unit; of the Mark Wainwright Analytical Centre; University of New South Wales; Sydney NSW 2052 Australia
- Australian Centre for Nanomedicine; University of New South Wales; Sydney NSW 2052 Australia
| | - Richard D. Tilley
- School of Chemistry and Electron Microscopy Unit; of the Mark Wainwright Analytical Centre; University of New South Wales; Sydney NSW 2052 Australia
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54
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Yang J, Fang H, Gao Y. Effect of Water Adsorption on the Photoluminescence of Silicon Quantum Dots. J Phys Chem Lett 2016; 7:1788-1793. [PMID: 27117881 DOI: 10.1021/acs.jpclett.6b00574] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The optical properties of silicon quantum dots (Si QDs) are strongly influenced by circumjacent surface-adsorbed molecules, which would highly affect their applications; however, water, as the ubiquitous environment, has not received enough attention yet. We employed the time-dependent density functional calculations to investigate the water effect of photoluminescence (PL) spectra for Si QDs. In contrast with the absorption spectra, PL spectra exhibit distinct characteristics. For Si32H38, PL presents the single maximum in the dry and humid environment, while the emission spectrum displays a dual-band fluorescence spectroscopy in the low-humidity environment. This phenomenon is also observed in the larger Si QDs. The distinct character in spectroscopy is dominated by the stretching of the Si-Si bond, which could be explained by the self-trapped exciton model. Our results shed light on the Si-water interaction that is important for the development of optical devices based on Si-coated surfaces.
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Affiliation(s)
- Jinrong Yang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Haiping Fang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
- Shanghai Science Research Center, Chinese Academy of Sciences , Shanghai 201204, China
| | - Yi Gao
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
- Shanghai Science Research Center, Chinese Academy of Sciences , Shanghai 201204, China
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55
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Hori Y, Kano S, Sugimoto H, Imakita K, Fujii M. Size-Dependence of Acceptor and Donor Levels of Boron and Phosphorus Codoped Colloidal Silicon Nanocrystals. NANO LETTERS 2016; 16:2615-2620. [PMID: 26998965 DOI: 10.1021/acs.nanolett.6b00225] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Size dependence of the boron (B) acceptor and phosphorus (P) donor levels of silicon (Si) nanocrystals (NCs) measured from the vacuum level was obtained in a very wide size range from 1 to 9 nm in diameter by photoemission yield spectroscopy and photoluminescence spectroscopy for B and P codoped Si-NCs. In relatively large Si-NCs, both levels are within the bulk Si band gap. The levels exhibited much smaller size dependence compared to the valence band and conduction band edges. The Fermi level of B and P codoped Si-NCs was also studied. It was found that the Fermi level of relatively large codoped Si-NCs is close to the valence band and it approaches the middle of the band gap with decreasing the size. The results suggest that below a certain size perfectly compensated Si-NCs, that is, Si-NCs with exactly the same number of active B and P, are preferentially grown, irrespective of average B and P concentrations in samples.
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Affiliation(s)
- Yusuke Hori
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University , Rokkodai, Nada, Kobe 657-8501, Japan
| | - Shinya Kano
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University , Rokkodai, Nada, Kobe 657-8501, Japan
| | - Hiroshi Sugimoto
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University , Rokkodai, Nada, Kobe 657-8501, Japan
| | - Kenji Imakita
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University , Rokkodai, Nada, Kobe 657-8501, Japan
| | - Minoru Fujii
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University , Rokkodai, Nada, Kobe 657-8501, Japan
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56
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Lee BG, Luo JW, Neale NR, Beard MC, Hiller D, Zacharias M, Stradins P, Zunger A. Quasi-Direct Optical Transitions in Silicon Nanocrystals with Intensity Exceeding the Bulk. NANO LETTERS 2016; 16:1583-1589. [PMID: 26898670 DOI: 10.1021/acs.nanolett.5b04256] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Comparison of the measured absolute absorption cross section on a per Si atom basis of plasma-synthesized Si nanocrystals (NCs) with the absorption of bulk crystalline Si shows that while near the band edge the NC absorption is weaker than the bulk, yet above ∼ 2.2 eV the NC absorbs up to 5 times more than the bulk. Using atomistic screened pseudopotential calculations we show that this enhancement arises from interface-induced scattering that enhances the quasi-direct, zero-phonon transitions by mixing direct Γ-like wave function character into the indirect X-like conduction band states, as well as from space confinement that broadens the distribution of wave functions in k-space. The absorption enhancement factor increases exponentially with decreasing NC size and is correlated with the exponentially increasing direct Γ-like wave function character mixed into the NC conduction states. This observation and its theoretical understanding could lead to engineering of Si and other indirect band gap NC materials for optical and optoelectronic applications.
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Affiliation(s)
- Benjamin G Lee
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Jun-Wei Luo
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Nathan R Neale
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Matthew C Beard
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Daniel Hiller
- Laboratory of Nanotechnology, IMTEK, Albert Ludwigs University , Freiburg 79110, Germany
| | - Margit Zacharias
- Laboratory of Nanotechnology, IMTEK, Albert Ludwigs University , Freiburg 79110, Germany
| | - Paul Stradins
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Alex Zunger
- Renewable and Sustainable Energy Institute, University of Colorado , Boulder, Colorado 80309, United States
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57
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Bergren MR, Palomaki PKB, Neale NR, Furtak TE, Beard MC. Size-Dependent Exciton Formation Dynamics in Colloidal Silicon Quantum Dots. ACS NANO 2016; 10:2316-23. [PMID: 26811876 DOI: 10.1021/acsnano.5b07073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We report size-dependent exciton formation dynamics within colloidal silicon quantum dots (Si QDs) using time-resolved terahertz (THz) spectroscopy measurements. THz photoconductivity measurements are used to distinguish the initially created hot carriers from excitons that form at later times. At early pump/probe delays, the exciton formation dynamics are revealed by the temporal evolution of the THz transmission. We find an increase in the exciton formation time, from ∼500 to ∼900 fs, as the Si QD diameter is reduced from 7.3 to 3.4 nm and all sizes exhibit slower hot-carrier relaxation times compared to bulk Si. In addition, we determine the THz absorption cross section at early delay times is proportional to the carrier mobility while at later delays is proportional to the exciton polarizability, αX. We extract a size-dependent αX and find an ∼r(4) dependence, consistent with previous reports for quantum-confined excitons in CdSe, InAs, and PbSe QDs. The observed slowing in exciton formation time for smaller Si QDs is attributed to decreased electron-phonon coupling due to increased quantum confinement. These results experimentally verify the modification of hot-carrier relaxation rates by quantum confinement in Si QDs, which likely plays a significant role in the high carrier multiplication efficiency observed in these nanomaterials.
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Affiliation(s)
- Matthew R Bergren
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
- Physics Department, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Peter K B Palomaki
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Nathan R Neale
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Thomas E Furtak
- Physics Department, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Matthew C Beard
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
- Physics Department, Colorado School of Mines , Golden, Colorado 80401, United States
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58
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Grydlik M, Hackl F, Groiss H, Glaser M, Halilovic A, Fromherz T, Jantsch W, Schäffler F, Brehm M. Lasing from Glassy Ge Quantum Dots in Crystalline Si. ACS PHOTONICS 2016; 3:298-303. [PMID: 26937421 PMCID: PMC4759615 DOI: 10.1021/acsphotonics.5b00671] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Indexed: 05/25/2023]
Abstract
Semiconductor light-emitters compatible with standard Si integration technology (SIT) are of particular interest for overcoming limitations in the operating speed of microelectronic devices. Light sources based on group IV elements would be SIT-compatible, but suffer from the poor optoelectronic properties of bulk Si and Ge. Here we demonstrate that epitaxially grown Ge quantum dots (QDs) in a defect-free Si matrix show extraordinary optical properties if partially amorphized by Ge-ion bombardment (GIB). In contrast to conventional SiGe nanostructures, these QDs exhibit dramatically shortened carrier lifetimes and negligible thermal quenching of the photoluminescence (PL) up to room temperature. Microdisk resonators with embedded GIB-QDs exhibit threshold behavior as well as a superlinear increase of the integrated PL intensity with concomitant line width narrowing as the pump power increases. These findings demonstrate light amplification by stimulated emission in a fully SIT-compatible group IV nanosystem.
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Affiliation(s)
| | - Florian Hackl
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
| | - Heiko Groiss
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
| | - Martin Glaser
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
| | - Alma Halilovic
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
| | - Thomas Fromherz
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
| | - Wolfgang Jantsch
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
| | - Friedrich Schäffler
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenbergerstrasse
69, A-4040 Linz, Austria
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59
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Limpens R, Luxembourg SL, Weeber AW, Gregorkiewicz T. Emission efficiency limit of Si nanocrystals. Sci Rep 2016; 6:19566. [PMID: 26786062 PMCID: PMC4726123 DOI: 10.1038/srep19566] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/15/2015] [Indexed: 11/09/2022] Open
Abstract
One of the important obstacles on the way to application of Si nanocrystals for development of practical devices is their typically low emissivity. In this study we explore the limits of external quantum yield of photoluminescence of solid-state dispersions of Si nanocrystals in SiO2. By making use of a low-temperature hydrogen passivation treatment we demonstrate a maximum emission quantum efficiency of approximately 35%. This is the highest value ever reported for this type of material. By cross-correlating PL lifetime with EQE values, we obtain a comprehensive understanding of the efficiency limiting processes induced by Pb-defects. We establish that the observed record efficiency corresponds to an interface density of Pb-centers of 1.3 × 10(12) cm(12), which is 2 orders of magnitude higher than for the best Si/SiO2 interface. This result implies that Si nanocrystals with up to 100% emission efficiency are feasible.
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Affiliation(s)
- Rens Limpens
- Van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | | | - Arthur W. Weeber
- ECN Solar Energy, PO Box 1, 1755 ZG Petten, The Netherlands
- Photovoltaic Materials and Devices, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - Tom Gregorkiewicz
- Van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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60
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Size confinement of Si nanocrystals in multinanolayer structures. Sci Rep 2015; 5:17289. [PMID: 26603483 PMCID: PMC4658553 DOI: 10.1038/srep17289] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/28/2015] [Indexed: 11/09/2022] Open
Abstract
Si nanocrystals (NCs) are often prepared by thermal annealing of multiple stacks of alternating sub-stoichiometric SiOx and SiO2 nanolayers. It is frequently claimed that in these structures, the NC diameter can be predefined by the thickness of the SiOx layer, while the NC concentration is independently controlled by the stoichiometry parameter x. However, several detailed structural investigations report that the NC size confinement to within the thickness of the SiOx layer is not strictly obeyed. In this study we address these contradicting findings: based on cross-correlation between structural and optical characterization of NCs grown in a series of purposefully prepared samples of different stoichiometry and layer thickness, we develop a comprehensive understanding of NC formation by Si precipitation in multinanolayer structures. We argue that the narrow NC size distribution generally observed in these materials appears due to reduction of the Si diffusion range, imposed by the SiO2 spacer layer. Therefore, both the SiOx layer thickness and composition as well as the actual thickness of the SiO2 spacer play an essential role in the NC formation.
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61
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Miller JB, Dandu N, Velizhanin KA, Anthony RJ, Kortshagen UR, Kroll DM, Kilina S, Hobbie EK. Enhanced Luminescent Stability through Particle Interactions in Silicon Nanocrystal Aggregates. ACS NANO 2015; 9:9772-9782. [PMID: 26348831 DOI: 10.1021/acsnano.5b02676] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Close-packed assemblies of ligand-passivated colloidal nanocrystals can exhibit enhanced photoluminescent stability, but the origin of this effect is unclear. Here, we use experiment, simulation, and ab initio computation to examine the influence of interparticle interactions on the photoluminescent stability of silicon nanocrystal aggregates. The time-dependent photoluminescence emitted by structures ranging in size from a single quantum dot to agglomerates of more than a thousand is compared with Monte Carlo simulations of noninteracting ensembles using measured single-particle blinking data as input. In contrast to the behavior typically exhibited by the metal chalcogenides, the measured photoluminescent stability shows an enhancement with respect to the noninteracting scenario with increasing aggregate size. We model this behavior using time-dependent density functional theory calculations of energy transfer between neighboring nanocrystals as a function of nanocrystal size, separation, and the presence of charge and/or surface-passivation defects. Our results suggest that rapid exciton transfer from "bright" nanocrystals to surface trap states in nearest-neighbors can efficiently fill such traps and enhance the stability of emission by promoting the radiative recombination of slowly diffusing excited electrons.
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Affiliation(s)
- Joseph B Miller
- North Dakota State University , Fargo, North Dakota 58108, United States
| | - Naveen Dandu
- North Dakota State University , Fargo, North Dakota 58108, United States
| | - Kirill A Velizhanin
- Theoretical Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Rebecca J Anthony
- University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Uwe R Kortshagen
- University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Daniel M Kroll
- North Dakota State University , Fargo, North Dakota 58108, United States
| | - Svetlana Kilina
- North Dakota State University , Fargo, North Dakota 58108, United States
| | - Erik K Hobbie
- North Dakota State University , Fargo, North Dakota 58108, United States
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62
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Dutta M, Thirugnanam L, Trinh PV, Fukata N. High Efficiency Hybrid Solar Cells Using Nanocrystalline Si Quantum Dots and Si Nanowires. ACS NANO 2015; 9:6891-6899. [PMID: 26167772 DOI: 10.1021/acsnano.5b03268] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report on an efficient hybrid Si nanocrystal quantum dot modified radial p-n junction thinner Si solar cell that utilizes the advantages of effective exciton collection by energy transfer from nanocrystal-Si (nc-Si) quantum dots to underlying radial p-n junction Si nanowire arrays with excellent carrier separation and propagation via the built-in electric fields of radial p-n junctions. Minimization of recombination, optical, and spectrum losses in this hybrid structure led to a high cell efficiency of 12.9%.
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Affiliation(s)
- Mrinal Dutta
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Lavanya Thirugnanam
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Pham Van Trinh
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Naoki Fukata
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
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63
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Nurbawono A, Liu S, Zhang C. Modeling optical properties of silicon clusters by first principles: From a few atoms to large nanocrystals. J Chem Phys 2015; 142:154705. [DOI: 10.1063/1.4918588] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Argo Nurbawono
- Department of Physics and the Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore
| | - Shuanglong Liu
- Department of Physics and the Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore
| | - Chun Zhang
- Department of Physics and the Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore
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64
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Sun H, Wang M, Wang J, Tian M, Wang H, Sun Z, Huang P. Development of magnetic separation and quantum dots labeled immunoassay for the detection of mercury in biological samples. J Trace Elem Med Biol 2015; 30:37-42. [PMID: 25744508 DOI: 10.1016/j.jtemb.2015.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 12/14/2014] [Accepted: 01/14/2015] [Indexed: 10/24/2022]
Abstract
A rapid and sensitive immunoassays of mercury (Hg) in biological samples was developed using quantum dots (QDs) and magnetic beads (MBs) as fluorescent and separated probes, respectively. A monoclonal antibody (mAb) that recognizes an Hg detection antigen (BSA-DTPA-Hg) complex was produced by the injection of BALB/c mice with an Hg immunizing antigen (KLH-DTPA-Hg). Then the ascites monoclonal antibodies were purified. The Hg monoclonal antibody (Hg-mAb) is conjugated with MBs to separate Hg from biological samples, and the other antibody, which is associated with QDs, is used to detect the fluorescence. The Hg in biological samples can be quantified using the relationship between the QDs fluorescence intensity and the concentration of Hg in biological samples following magnetic separation. In this method, the detection linear range is 1-1000ng/mL, and the minimum detection limit is 1ng/mL. The standard addition recovery rate was 94.70-101.18%. The relative standard deviation values were 2.76-7.56%. Furthermore, the Hg concentration can be detected in less than 30min, the significant interference of other heavy metals can be avoided, and the simultaneous testing of 96 samples can be performed. These results indicate that the method could be used for rapid monitoring Hg in the body.
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Affiliation(s)
- Hubo Sun
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China
| | - Mengmeng Wang
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China
| | - Jilong Wang
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China
| | - Mi Tian
- Medical Experiment and Test Center, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China
| | - Hui Wang
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China
| | - Zhiwei Sun
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China
| | - Peili Huang
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China.
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65
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Höhlein IMD, Angı A, Sinelnikov R, Veinot JGC, Rieger B. Functionalization of Hydride-Terminated Photoluminescent Silicon Nanocrystals with Organolithium Reagents. Chemistry 2014; 21:2755-8. [DOI: 10.1002/chem.201405555] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Indexed: 11/10/2022]
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Saeed S, Buters F, Dohnalova K, Wosinski L, Gregorkiewicz T. Structural and optical characterization of self-assembled Ge nanocrystal layers grown by plasma-enhanced chemical vapor deposition. NANOTECHNOLOGY 2014; 25:405705. [PMID: 25224861 DOI: 10.1088/0957-4484/25/40/405705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a structural and optical study of solid-state dispersions of Ge nanocrystals prepared by plasma-enhanced chemical vapor deposition. Structural analysis shows the presence of nanocrystalline germanium inclusions embedded in an amorphous matrix of Si-rich SiO(2).Optical characterization reveals two prominent emission bands centered around 2.6 eV and 3.4 eV, and tunable by excitation energy. In addition, the lower energy band shows an excitation power-dependent blue shift of up to 0.3 eV. Decay dynamics of the observed emission contains fast (nanosecond) and slow (microseconds) components, indicating contributions of several relaxation channels. Based on these material characteristics, a possible microscopic origin of the individual emission bands is discussed.
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