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Search for "excitons" in Full Text gives 63 result(s) in Beilstein Journal of Nanotechnology.

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

  • Parul Chawla,
  • Son Singh and
  • Shailesh Narain Sharma

Beilstein J. Nanotechnol. 2014, 5, 1235–1244, doi:10.3762/bjnano.5.137

Graphical Abstract
  • polymer P3HT, the generation of excitons takes place (process 1). The excitons then diffuse to the polymer–chalcopyrite interface where charge separation occurs (process 2). The overall energetic driving force ∆E for the electron transfer from the donor to the acceptor depends on the energy difference
  • the D/A interface, electron–hole pairs may remain coulombically bound and therefore susceptible to interfacial recombination. The local junction morphology and the crystallinity of both organic and inorganic components greatly affects such charge-transfer (CT) excitons. In the present case (Figure 11
  • . Generation of excitons (1), charge separation (2) and current generation (3) for (a) P3HT:CISe, (b) P3HT:CIGSe and (c) P3HT:CZTSe nanocomposites. Acknowledgements The authors are grateful to Prof. R.C. Budhani, Director (NPL) for his constant support and guidance. The authors gratefully acknowledge funding
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Published 08 Aug 2014

Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

  • Claudio Davet Gutiérrez-Lazos,
  • Mauricio Ortega-López,
  • Manuel A. Pérez-Guzmán,
  • A. Mauricio Espinoza-Rivas,
  • Francisco Solís-Pomar,
  • Rebeca Ortega-Amaya,
  • L. Gerardo Silva-Vidaurri,
  • Virginia C. Castro-Peña and
  • Eduardo Pérez-Tijerina

Beilstein J. Nanotechnol. 2014, 5, 881–886, doi:10.3762/bjnano.5.100

Graphical Abstract
  • technique to assess the structure of semiconductors also at the nanometer-scale. In particular, Raman spectroscopy is sensitive to size effects, because like the excitons, phonons experience quantum confinement effects depending on the crystal size. In CdTe, the quantum confinement effect is revealed by the
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Published 20 Jun 2014

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag2CrO4

  • Difa Xu,
  • Shaowen Cao,
  • Jinfeng Zhang,
  • Bei Cheng and
  • Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

Graphical Abstract
  • the smaller particle size, higher surface area, relatively stronger light absorption, and blue-shift absorption edge, which result in the adsorption of more MB molecules, a shorter diffusion process of more photogenerated excitons, and a stronger oxidation ability of the photogenerated holes
  • Ag2CrO4photocatalyst shows the best activity in the photodegradation of a MB aqueous solution, because of the higher adsorption of MB molecules, shorter diffusion process of more photogenerated excitons, and stronger oxidation ability of the photogenerated holes. The current investigation may provide new insight into
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Published 19 May 2014

Preparation of poly(N-vinylpyrrolidone)-stabilized ZnO colloid nanoparticles

  • Tatyana Gutul,
  • Emil Rusu,
  • Nadejda Condur,
  • Veaceslav Ursaki,
  • Evgenii Goncearenco and
  • Paulina Vlazan

Beilstein J. Nanotechnol. 2014, 5, 402–406, doi:10.3762/bjnano.5.47

Graphical Abstract
  • -bandgap luminescence with a maximum at 376 nm, which coincides with that observed in high-quality ZnO bulk crystals and is related to the recombination of free excitons. The observation of efficient free exciton emission at room temperature, as well as the weak visible emission observed at 550 nm is
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Published 03 Apr 2014

Many-body effects in semiconducting single-wall silicon nanotubes

  • Wei Wei and
  • Timo Jacob

Beilstein J. Nanotechnol. 2014, 5, 19–25, doi:10.3762/bjnano.5.2

Graphical Abstract
  • SiNTs from 0.65, 0.28 and 0.05 eV at DFT level to 1.9, 1.22 and 0.79 eV at GW level. The Coulomb electron−hole (e−h) interactions significantly modify optical absorption properties obtained at noninteracting-particle level with the formation of bound excitons with considerable binding energies (of the
  • ; excitons; GW approximation; many body effects; silicon; Introduction Silicon nanotubes [1][2][3][4][5] (SiNTs) have been demonstrated to be emerging materials with exclusive applications in micro- and nanoelectronics [6][7][8][9][10][11][12]. An extra advantage of SiNTs lies in the natural compatibility
  • screening leads to the formation of excitonic resonances or strongly bound excitons with considerable binding energies. Therefore, many-body effects [18][19][20][21][22][23][24][25][26][27][28][29][30][31] are required to understand this kind of systems sufficiently, especially their single-particle
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Published 06 Jan 2014

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

  • Adib Abou Chaaya,
  • Roman Viter,
  • Mikhael Bechelany,
  • Zanda Alute,
  • Donats Erts,
  • Anastasiya Zalesskaya,
  • Kristaps Kovalevskis,
  • Vincent Rouessac,
  • Valentyn Smyntyna and
  • Philippe Miele

Beilstein J. Nanotechnol. 2013, 4, 690–698, doi:10.3762/bjnano.4.78

Graphical Abstract
  • electric field of the surface charge in the depletion layer would stimulate dissociation of excitons in ZnO [18][48]. The absorption spectra of ultrathin ZnO ALD films show that the defect states are present in the gap. The defect states at 3.08–3.14 eV formed by neutral Zn vacancies and oxygen
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Published 28 Oct 2013

Photoresponse from single upright-standing ZnO nanorods explored by photoconductive AFM

  • Igor Beinik,
  • Markus Kratzer,
  • Astrid Wachauer,
  • Lin Wang,
  • Yuri P. Piryatinski,
  • Gerhard Brauer,
  • Xin Yi Chen,
  • Yuk Fan Hsu,
  • Aleksandra B. Djurišić and
  • Christian Teichert

Beilstein J. Nanotechnol. 2013, 4, 208–217, doi:10.3762/bjnano.4.21

Graphical Abstract
  • the emission of localized excitons. Therefore, the absorption of light with photon energies of 3.2 eV and higher may lead to the generation of excitons with possible subsequent dissociation into free charge carriers. The broad band visible in Figure 2b (integral spectrum) with the maximum at 504 nm is
  • photon energy ≥ 3.2 eV under the formation of free excitons, indicative of the possible presence of oxygen vacancies. Based on the latter findings, we conclude that the experimentally observed photocurrent cannot be simply explained by band-to-band transition with subsequent electron–hole pair
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Published 21 Mar 2013

Horizontal versus vertical charge and energy transfer in hybrid assemblies of semiconductor nanoparticles

  • Gilad Gotesman,
  • Rahamim Guliamov and
  • Ron Naaman

Beilstein J. Nanotechnol. 2012, 3, 629–636, doi:10.3762/bjnano.3.72

Graphical Abstract
  • to receive excitons from the donors. Therefore, this ability is controlled by the interactions among the acceptor NPs that are coupled through the DT molecules. The observed results indicate that here the energy transfer process probably occurs by the Dexter mechanism, since the Förster mechanism
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Published 06 Sep 2012

Low-temperature synthesis of carbon nanotubes on indium tin oxide electrodes for organic solar cells

  • Andrea Capasso,
  • Luigi Salamandra,
  • Aldo Di Carlo,
  • John M. Bell and
  • Nunzio Motta

Beilstein J. Nanotechnol. 2012, 3, 524–532, doi:10.3762/bjnano.3.60

Graphical Abstract
  • percolation paths created by the CNTs, which can effectively drive away the free carriers generated from the dissociation of the excitons at the dispersed heterojunctions. We observe, however, that the Jsc exhibits a noteworthy 40% increase in the case of cell C, but it does not vary much for sample C1. This
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Published 19 Jul 2012

Structural, electronic and photovoltaic characterization of multiwalled carbon nanotubes grown directly on stainless steel

  • Luca Camilli,
  • Manuela Scarselli,
  • Silvano Del Gobbo,
  • Paola Castrucci,
  • Eric Gautron and
  • Maurizio De Crescenzi

Beilstein J. Nanotechnol. 2012, 3, 360–367, doi:10.3762/bjnano.3.42

Graphical Abstract
  • electronic structures close to the π-plasmon, which can be assigned to transitions between Van Hove singularities and which explains the ability of CNTs to create electron–hole pairs (excitons) under illumination by light. These features are completely absent in HOPG, for which the π-plasmon peak has a sharp
  • different geometries (in-plane and top-down) to study the role played by the excitons generated in the MWCNTs. In the in-plane configuration the main contribution to the photocurrent comes from the MWCNTs, while in the top-down setup the role of silicon dominates, because the excitons generated in the
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Published 02 May 2012

Optical properties of fully conjugated cyclo[n]thiophenes – An experimental and theoretical approach

  • Elena Mena-Osteritz,
  • Fan Zhang,
  • Günther Götz,
  • Peter Reineker and
  • Peter Bäuerle

Beilstein J. Nanotechnol. 2011, 2, 720–726, doi:10.3762/bjnano.2.78

Graphical Abstract
  • previous theoretical work we showed that the optical excitations of thiophene-based linear and cyclic oligomers can be described by Frenkel excitons, which are delocalized over the oligomeric π-system [12][30]. Concerning the macrocycles of series I and II, we assume, as a first approach, that the
  • is distributed along the ring. These findings strongly corroborate the description of the electronic excitations by the model based on Frenkel excitons, despite the limitations assumed in this approach. A series of improvements of the model can be adopted in the future. Conclusion Oligothiophene
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Published 25 Oct 2011

Schottky junction/ohmic contact behavior of a nanoporous TiO2 thin film photoanode in contact with redox electrolyte solutions

  • Masao Kaneko,
  • Hirohito Ueno and
  • Junichi Nemoto

Beilstein J. Nanotechnol. 2011, 2, 127–134, doi:10.3762/bjnano.2.15

Graphical Abstract
  • the FTO. When TiO2 is excited by UV light, excitons are formed, but many of these would recombine simply wasting the excitation energy if band bending did not exist. However, due to the band bending in the space charge layer formed at the TiO2/liquid interface, the excitons formed here would be
  • layer holes (h+) of the excitons (excited e−–h+ couples, red circle) migrate in the VB onto the TiO2 surface reacting with the e− donor, and electrons (e−) of the exciton migrate into the bulk CB where e− then migrate through TiO2 grain boundaries and finally into the conductive layer on FTO. It should
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Published 28 Feb 2011

Oriented growth of porphyrin-based molecular wires on ionic crystals analysed by nc-AFM

  • Thilo Glatzel,
  • Lars Zimmerli,
  • Shigeki Kawai,
  • Ernst Meyer,
  • Leslie-Anne Fendt and
  • Francois Diederich

Beilstein J. Nanotechnol. 2011, 2, 34–39, doi:10.3762/bjnano.2.4

Graphical Abstract
  • transport of electrons and/or excitons along specific directions. Compared to semiconductor based devices, self-assembled molecules provide some distinct advantages such as self-healing [1] and a decreased number of defects [2][3][4]. For some time, studies on molecular growth were limited to metal
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Published 13 Jan 2011
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