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Author |
Cambré, S.; Campo, J.; Beirnaert, C.; Verlackt, C.; Cool, P.; Wenseleers, W. |
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Title |
Asymmetric dyes align inside carbon nanotubes to yield a large nonlinear optical response |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Nature nanotechnology |
Abbreviated Journal |
Nat Nanotechnol |
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Volume |
10 |
Issue |
10 |
Pages |
248-252 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Nanostructured and organic optical and electronic materials (NANOrOPT); Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Asymmetric dye molecules have unusual optical and electronic properties1, 2, 3. For instance, they show a strong second-order nonlinear optical (NLO) response that has attracted great interest for potential applications in electro-optic modulators for optical telecommunications and in wavelength conversion of lasers2, 3. However, the strong Coulombic interaction between the large dipole moments of these molecules favours a pairwise antiparallel alignment that cancels out the NLO response when incorporated into bulk materials. Here, we show that by including an elongated dipolar dye (p,p′-dimethylaminonitrostilbene, DANS, a prototypical asymmetric dye with a strong NLO response4) inside single-walled carbon nanotubes (SWCNTs)5, 6, an ideal head-to-tail alignment in which all electric dipoles point in the same sense is naturally created. We have applied this concept to synthesize solution-processible DANS-filled SWCNTs that show an extremely large total dipole moment and static hyperpolarizability (β0 = 9,800 × 10−30 e.s.u.), resulting from the coherent alignment of arrays of ∼70 DANS molecules. |
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Wos |
000350799700016 |
Publication Date |
2015-02-02 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-3387;1748-3395; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
38.986 |
Times cited |
46 |
Open Access |
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Notes |
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Approved |
Most recent IF: 38.986; 2015 IF: 34.048 |
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Call Number |
c:irua:125405 |
Serial |
158 |
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Permanent link to this record |
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Author |
Godefroo, S.; Hayne, M.; Jivanescu, M.; Stesmans, A.; Zacharias, M.; Lebedev, O.I.; Van Tendeloo, G.; Moshchalkov, V.V. |
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Title |
Classification and control of the origin of photoluminescence from Si nanocrystals |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
Nature nanotechnology |
Abbreviated Journal |
Nat Nanotechnol |
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Volume |
3 |
Issue |
3 |
Pages |
174-178 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Silicon dominates the electronics industry, but its poor optical properties mean that III-V compound semiconductors are preferred for photonics applications. Photoluminescence at visible wavelengths was observed from porous Si at room temperature in 1990, but the origin of these photons (do they arise from highly localized defect states or quantum confinement effects?) has been the subject of intense debate ever since. Attention has subsequently shifted from porous Si to Si nanocrystals, but the same fundamental question about the origin of the photoluminescence has remained. Here we show, based on measurements in high magnetic fields, that defects are the dominant source of light from Si nanocrystals. Moreover, we show that it is possible to control the origin of the photoluminescence in a single sample: passivation with hydrogen removes the defects, resulting in photoluminescence from quantum-confined states, but subsequent ultraviolet illumination reintroduces the defects, making them the origin of the light again. |
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Wos |
000254743600017 |
Publication Date |
2008-03-02 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-3387;1748-3395; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
38.986 |
Times cited |
426 |
Open Access |
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Notes |
Fwo |
Approved |
Most recent IF: 38.986; 2008 IF: 20.571 |
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Call Number |
UA @ lucian @ c:irua:102630 |
Serial |
373 |
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Permanent link to this record |
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Author |
Talgorn, E.; Gao, Y.; Aerts, M.; Kunneman, L.T.; Schins, J.M.; Savenije, T.J.; van Huis, M.A.; van der Zant, H.S.J.; Houtepen, A.J.; Siebbeles, L.D.A. |
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Title |
Unity quantum yield of photogenerated charges and band-like transport in quantum-dot solids |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Nature nanotechnology |
Abbreviated Journal |
Nat Nanotechnol |
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Volume |
6 |
Issue |
11 |
Pages |
733-739 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Solid films of colloidal quantum dots show promise in the manufacture of photodetectors and solar cells. These devices require high yields of photogenerated charges and high carrier mobilities, which are difficult to achieve in quantum-dot films owing to a strong electronhole interaction and quantum confinement. Here, we show that the quantum yield of photogenerated charges in strongly coupled PbSe quantum-dot films is unity over a large temperature range. At high photoexcitation density, a transition takes place from hopping between localized states to band-like transport. These strongly coupled quantum-dot films have electrical properties that approach those of crystalline bulk semiconductors, while retaining the size tunability and cheap processing properties of colloidal quantum dots. |
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Wos |
000296737300012 |
Publication Date |
2011-09-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-3387;1748-3395; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
38.986 |
Times cited |
129 |
Open Access |
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Notes |
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Approved |
Most recent IF: 38.986; 2011 IF: 27.270 |
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Call Number |
UA @ lucian @ c:irua:93296 |
Serial |
3813 |
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Permanent link to this record |
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Author |
Jiang, Y.; Mao, J.; Moldovan, D.; Masir, M.R.; Li, G.; Watanabe, K.; Taniguchi, T.; Peeters, F.M.; Andrei, E.Y. |
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Title |
Tuning a circular p-n junction in graphene from quantum confinement to optical guiding |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Nature nanotechnology |
Abbreviated Journal |
Nat Nanotechnol |
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Volume |
12 |
Issue |
11 |
Pages |
1045-+ |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
<script type='text/javascript'>document.write(unpmarked('The photon-like propagation of the Dirac electrons in graphene, together with its record-high electronic mobility(1-3), can lead to applications based on ultrafast electronic response and low dissipation(4-6). However, the chiral nature of the charge carriers that is responsible for the high mobility also makes it difficult to control their motion and prevents electronic switching. Here, we show how to manipulate the charge carriers by using a circular p-n junction whose size can be continuously tuned from the nanometre to the micrometre scale(7,8). The junction size is controlled with a dual-gate device consisting of a planar back gate and a point-like top gate made by decorating a scanning tunnelling microscope tip with a gold nanowire. The nanometre-scale junction is defined by a deep potential well created by the tip-induced charge. It traps the Dirac electrons in quantum-confined states, which are the graphene equivalent of the atomic collapse states (ACSs) predicted to occur at supercritically charged nuclei(9-13). As the junction size increases, the transition to the optical regime is signalled by the emergence of whispering-gallery modes(14-16), similar to those observed at the perimeter of acoustic or optical resonators, and by the appearance of a Fabry-Perot interference pattern(17-20) for junctions close to a boundary.')); |
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Wos |
000414531800011 |
Publication Date |
2017-09-15 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-3387; 1748-3395 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
38.986 |
Times cited |
65 |
Open Access |
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Notes |
; The authors acknowledge funding provided by DOE-FG02-99ER45742 (STM/STS) and NSF DMR 1708158 (fabrication). Theoretical work was supported by ESF-EUROCORES-EuroGRAPHENE, FWO VI and the Methusalem program of the Flemish government. ; |
Approved |
Most recent IF: 38.986 |
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Call Number |
UA @ lucian @ c:irua:147406 |
Serial |
4902 |
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Permanent link to this record |
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Author |
Hu, S.; Gopinadhan, K.; Rakowski, A.; Neek-Amal, M.; Heine, T.; Grigorieva, I.V.; Haigh, S.J.; Peeters, F.M.; Geim, A.K.; Lozada-Hidalgo, M. |
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Title |
Transport of hydrogen isotopes through interlayer spacing in van der Waals crystals |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Nature nanotechnology |
Abbreviated Journal |
Nat Nanotechnol |
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Volume |
13 |
Issue |
6 |
Pages |
468-+ |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
Atoms start behaving as waves rather than classical particles if confined in spaces commensurate with their de Broglie wavelength. At room temperature this length is only about one angstrom even for the lightest atom, hydrogen. This restricts quantum-confinement phenomena for atomic species to the realm of very low temperatures(1-5). Here, we show that van der Waals gaps between atomic planes of layered crystals provide angstrom-size channels that make quantum confinement of protons apparent even at room temperature. Our transport measurements show that thermal protons experience a notably higher barrier than deuterons when entering van der Waals gaps in hexagonal boron nitride and molybdenum disulfide. This is attributed to the difference in the de Broglie wavelengths of the isotopes. Once inside the crystals, transport of both isotopes can be described by classical diffusion, albeit with unexpectedly fast rates comparable to that of protons in water. The demonstrated angstrom-size channels can be exploited for further studies of atomistic quantum confinement and, if the technology can be scaled up, for sieving hydrogen isotopes. |
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Wos |
000434715700015 |
Publication Date |
2018-04-04 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-3387; 1748-3395 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
38.986 |
Times cited |
32 |
Open Access |
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Notes |
; The authors acknowledge support from the Lloyd's Register Foundation, EPSRC – EP/N010345/1, the European Research Council ARTIMATTER project – ERC-2012-ADG and from Graphene Flagship. M.L.-H. acknowledges a Leverhulme Early Career Fellowship. ; |
Approved |
Most recent IF: 38.986 |
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Call Number |
UA @ lucian @ c:irua:152014UA @ admin @ c:irua:152014 |
Serial |
5046 |
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Permanent link to this record |
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Author |
Mogg, L.; Hao, G.-P.; Zhang, S.; Bacaksiz, C.; Zou, Y.; Haigh, S.J.; Peeters, F.M.; Geim, A.K.; Lozada-Hidalgo, M. |
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Title |
Atomically thin micas as proton-conducting membranes |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Nature nanotechnology |
Abbreviated Journal |
Nat Nanotechnol |
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Volume |
14 |
Issue |
10 |
Pages |
962-+ |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
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Abstract |
Monolayers of graphene and hexagonal boron nitride (hBN) are highly permeable to thermal protons1,2. For thicker two-dimensional (2D) materials, proton conductivity diminishes exponentially, so that, for example, monolayer MoS2 that is just three atoms thick is completely impermeable to protons1. This seemed to suggest that only one-atom-thick crystals could be used as proton-conducting membranes. Here, we show that few-layer micas that are rather thick on the atomic scale become excellent proton conductors if native cations are ion-exchanged for protons. Their areal conductivity exceeds that of graphene and hBN by one to two orders of magnitude. Importantly, ion-exchanged 2D micas exhibit this high conductivity inside the infamous gap for proton-conducting materials3, which extends from ∼100 °C to 500 °C. Areal conductivity of proton-exchanged monolayer micas can reach above 100 S cm−2 at 500 °C, well above the current requirements for the industry roadmap4. We attribute the fast proton permeation to ~5-Å-wide tubular channels that perforate micas’ crystal structure, which, after ion exchange, contain only hydroxyl groups inside. Our work indicates that there could be other 2D crystals5 with similar nanometre-scale channels, which could help close the materials gap in proton-conducting applications. |
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Place of Publication |
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Editor |
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Language |
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Wos |
000488977100016 |
Publication Date |
2019-09-02 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-3387; 1748-3395 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
38.986 |
Times cited |
44 |
Open Access |
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Notes |
; The work was supported by the Lloyd's Register Foundation, the Engineering and Physical Sciences Research Council (EPSRC)-EP/N010345/1, EP/M010619/1 and EP/ P009050/1, the European Research Council, the Graphene Flagship and the Royal Society. M.L.-H. acknowledges a Leverhulme Early Career Fellowship, G.-P.H. acknowledges a Marie Curie International Incoming Fellowship, and L.M. acknowledges the EPSRC NOWNano programme for funding. Y.Z. acknowledges the assistance of Eric Prestat in TEM specimen preparation. Computational resources were provided by the TUBITAK ULAKBIM High Performance and Grid Computing Center (TR-Grid e-Infrastructure). ; |
Approved |
Most recent IF: 38.986 |
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Call Number |
UA @ admin @ c:irua:163589 |
Serial |
5407 |
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Permanent link to this record |