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

• -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

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

• 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

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

• 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

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

• 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

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

• 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

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

• 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

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

• 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

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

• 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

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

• 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

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

• 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