Inorganic Janus particles for biomedical applications

• Isabel Schick,
• Steffen Lorenz,
• Dominik Gehrig,
• Stefan Tenzer,
• Wiebke Storck,
• Karl Fischer,
• Dennis Strand,
• Frédéric Laquai and
• Wolfgang Tremel

Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244

• enhanced optical characteristics such as high luminescence quantum yields [11][12], decreased fluorescence, as well as tunable emission color as a function of particle size and shell thickness. This optimization is governed by the depression of structural imperfections at the surface and the enhanced

• ]. The design of anisotropically shaped semiconductors is limited since the band-edge luminescence is further reduced due to a higher surface-to-volume ratio and the increased carrier delocalization lowering the probability of a radiative carrier recombination [10], but their major drawback, the

Influence of the supramolecular architecture on the magnetic properties of a Dy^III single-molecule magnet: an ab initio investigation

• Julie Jung,
• Olivier Cador,
• Kevin Bernot,
• Fabrice Pointillart,
• Javier Luzon and
• Boris Le Guennic

Beilstein J. Nanotechnol. 2014, 5, 2267–2274, doi:10.3762/bjnano.5.236

• -crystal magnetometry, low temperature luminescence, and wavefunction-based ab initio calculations, has demonstrated that subtle modification of the DyIII environment such as the rotation of the water molecule is enough to be the driving force of the easy-axis orientation in such a molecule [40

Hybrid spin-crossover nanostructures

• Carlos M. Quintero,
• Gautier Félix,
• Iurii Suleimanov,
• José Sánchez Costa,
• Gábor Molnár,
• Lionel Salmon,
• William Nicolazzi and
• Azzedine Bousseksou

Beilstein J. Nanotechnol. 2014, 5, 2230–2239, doi:10.3762/bjnano.5.232

• manner, the luminescence will be modulated as the complex switches its spin state. Nonetheless, in order to render this approach valuable at the nanoscale, it is imperative to place the luminophore close to the metallic centers of the complex (≈1–3 nm) to establish a non-radiative energy transfer [31

• nano-patterned polydimethylsiloxane (PDMS) stamp. The luminescence of the isolated dots as a function of temperature increased upon the LS to HS spin transition and decreased as the LS state was restored at low temperatures. The synergy between luminescence and SCO properties in these hybrid systems

The gut wall provides an effective barrier against nanoparticle uptake

• Heike Sinnecker,
• Thorsten Krause,
• Sabine Koelling,
• Ingmar Lautenschläger and
• Andreas Frey

Beilstein J. Nanotechnol. 2014, 5, 2092–2101, doi:10.3762/bjnano.5.218

• multi-mode microplate reader (SpectraMax M5; Molecular Devices, Biberach an der Riss, Germany) at excitation/emission wavelengths of 480/515 nm. The luminescence of the europium-containing 40 nm NPs was analyzed time resolved with a delay of 200 µs and an integration time of 1000 µs with excitation

• /emission wavelengths of 360/610 nm. The measured fluorescence/luminescence of every sample was transformed to particle numbers by comparison with a standard curve. Control experiments showed now alteration in the measured fluorescence when particles were suspended in any of the different solutes analyzed

Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• QDs with various small ligands, polymer-coated QDs and Fe–Pt NPs as well as DHLA-coated gold and silver nanoclusters (NCs) [49]. Affinity measurements on the latter NPs were performed by measuring their luminescence enhancement due to protein binding rather than by using FCS. For native HSA, the

Carbon nano-onions (multi-layer fullerenes): chemistry and applications

• Juergen Bartelmess and
• Silvia Giordani

Beilstein J. Nanotechnol. 2014, 5, 1980–1998, doi:10.3762/bjnano.5.207

• fluorescent CNO nanomaterial that accumulated in the organisms and could be observed by fluorescence microscopy. Control experiments with non-CNO fed specimens were performed, excluding auto-fluorescence as reason for the observed luminescence of the organisms. Following their initial work describing in vivo

• (green) and nuclei stain Hoechst (blue) (right). Reprinted with permission from [39]. Copyright 2013 John Wiley and Sons. Confocal images of azaBODIPY-CNOs in HeLa Kyoto cells (left) and BODIPY-CNOs in MCF-7 cells (right). The blue luminescence is due to Hoechst 33342 nuclear stain. Reproduced with

Carbon-based smart nanomaterials in biomedicine and neuroengineering

• Antonina M. Monaco and
• Michele Giugliano

Beilstein J. Nanotechnol. 2014, 5, 1849–1863, doi:10.3762/bjnano.5.196

• their magnetic properties [19]: Given the coupling between the spin state and luminescence, the luminescence of NDs can be modulated by local magnetic fields [20][21]. Graphene: Graphene is a mono-atomic, two-dimensional, sheet of sp2-hybridised carbon atoms arranged as a honeycomb lattice. Since the

Biocompatibility of cerium dioxide and silicon dioxide nanoparticles with endothelial cells

• Claudia Strobel,
• Martin Förster and
• Ingrid Hilger

Beilstein J. Nanotechnol. 2014, 5, 1795–1807, doi:10.3762/bjnano.5.190

• instructions. On the basis of the measured luminescence (LUMIStar Galaxy OPTIMA microplate reader, BMG LABTECH GmbH, Germany), the relative ATP content was calculated and normalized to corresponding untreated control cells. The threshold for cytotoxicity according to DIN EN ISO 10993-5:2009-10 was used as

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• comparable to traditional photovoltaic semiconductors, has been demonstrated [3]. Different approaches have been made to achieve light emission from group-IV semiconductor nanostructures despite the indirect nature of the energy gaps. The quantum confinement of carriers has led to efficient luminescence and

• luminescence intensity in the visible and near-infrared region. A size-dependent blue shift of the luminescence comparable to porous Si is well documented. Figure 1 shows PL spectra of Si NCs produced by ion implantation and subsequent annealing [34]. The emission is tuned by varying the implantation and

• result in either a quenching or an enhancement of the Si NCs PL, depending on the dopant concentration and NC sizes [28][35]. Crowe et al. [35] have shown that as phosphorus accumulates at the nanocrystal oxide interface it leads to the passivation of the dangling bonds as observed by the luminescence

Donor–acceptor graphene-based hybrid materials facilitating photo-induced electron-transfer reactions

• Anastasios Stergiou,
• Georgia Pagona and
• Nikos Tagmatarchis

Beilstein J. Nanotechnol. 2014, 5, 1580–1589, doi:10.3762/bjnano.5.170

• associating porphyrins with graphene was made by condensing an amino-modified tetraphenylporphyrin (TPP) to the carboxylic functionalities present in GO [44] providing the GO–TPP hybrid structure shown in Figure 2. The observed luminescence quenching of TPP in the GO–TPP hybrid material is indicative of a

Synthesis of hydrophobic photoluminescent carbon nanodots by using L-tyrosine and citric acid through a thermal oxidation route

• Venkatesh Gude

Beilstein J. Nanotechnol. 2014, 5, 1513–1522, doi:10.3762/bjnano.5.164

• CNDs are also soluble in water under basic conditions. The effects of base and silver nanoparticles on the luminescence properties of CNDs were studied and a quenching of fluorescence was observed. These tyrosine-passivated CNDs are applicable for both biologically and commercially. Keywords

• : composite materials; fluorescence quenching; hydrophobic; luminescence; upconversion; Introduction The synthesis of fluorescent functional materials raised significant interest in order to understand biological processes such as DNA sequencing, detection of DNA-hybridization, protein sensing, single

• -passivated CNDs are insoluble in water under normal conditions, but soluble under basic conditions. The luminescence properties of the CNDs were investigated in organic solvents and in water under basic conditions. The basic aqueous solution of the CNDs was used to prepare a composite material with silver

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

• Anh-Thu Thi Do,
• Hong Thai Giang,
• Thu Thi Do,
• Ngan Quang Pham and
• Giang Truong Ho

Beilstein J. Nanotechnol. 2014, 5, 1261–1267, doi:10.3762/bjnano.5.140

• transition between donor–acceptor pairs. In the Pd/ZnO sample, the excitonic band-edge emission completely vanished or was indistinct, while the structured green luminescence band and the transition shift of the emission maximum to higher energies was clearly visible. The second peak at 517 nm increased and

• the third peak at around 570 nm decreased. Interestingly, the obtained result is confirmed by the similarity of the luminescence bands of ZnO and ZnO:Cu [19][20][21]. The fine structure is assigned to the longitudinal optical phonon replica with an energy spacing of about 72 meV. This suggests that a

• green luminescence band originates from palladium ions, which replace zinc and always occur in ZnO in a small amount. The dominant peak at 517 nm corresponds to the exciton transition from the ground-state electronic subband to the ground-state of Pd in replacing Zn sites (i.e., PdZn vacancies). The

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

• luminescence intensity of the polymer to a considerable extent. The nanocrystals which lower the luminescence of the polymer the most are the best charge-transfer material from the polymer to nanocrystals. In our case, the best charge transfer capability is found for CZTSe nanocrystals. Further confirmation of

• between the polymer:CZTSe nanocomposites, that are contributing to the separated electron–hole pairs that ensues recombination non-radiatively. It is noteworthy that the quenching of the luminescence of P3HT only occurs to some extent even at high concentrations of chalcogenide nanocrystals. This could be

Surface processes during purification of InP quantum dots

• Natalia Mordvinova,
• Pavel Emelin,
• Alexander Vinokurov,
• Sergey Dorofeev,
• Artem Abakumov and
• Tatiana Kuznetsova

Beilstein J. Nanotechnol. 2014, 5, 1220–1225, doi:10.3762/bjnano.5.135

• precursor takes place, which leads to a better surface passivation. The electrophoretic purification technique does not increase luminescence efficiency but yields very pure quantum dots in only a few minutes. Additionally, the formation of In(OH)3 during the low temperature synthesis was explained

• method of purification, electrophoresis, is investigated and described in particular. Keywords: cadmium-free material; electrophoresis; luminescence; precipitation; purification; quantum dots; semiconductors; Introduction Colloidal semiconductor nanocrystals (NCs) have been studied extensively for the

• ampoules to monitor changes in the intensity of luminescence. Results and Discussion XRD shows that the QDs are pure InP nanocrystals (Figure 1). Figure 2a shows an overview HAADF-STEM image of the QDs that have a size ranging between 2 and 7 nm. The ring electron diffraction pattern (insert in Figure 2a

Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications

• Li-wei Liu,
• Si-yi Hu,
• Ying Pan,
• Jia-qi Zhang,
• Yue-shu Feng and
• Xi-he Zhang

Beilstein J. Nanotechnol. 2014, 5, 919–926, doi:10.3762/bjnano.5.105

• and obstetrics, China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130033, China 10.3762/bjnano.5.105 Abstract In this study, we report on CdS/ZnS nanocrystals as a luminescence probe for bioimaging applications. CdS nanocrystals capped with a ZnS shell had enhanced luminescence

• ZnS protective shell not only enhances the brightness of the QDs but also improves their stability in a biological environment. An in-vivo imaging study showed that F127-CdS/ZnS micelles had strong luminescence. These results suggest that these nanoparticles have significant advantages for bioimaging

• bandgap (Eg) of 2.42 eV. By tailoring its composition and size, or surface functionality, it is possible to enhance luminescence emission and quantum yield of these QDs. The use of a coating agent can make CdS more stable. ZnS QDs are less cytotoxic than CdTe and CdSe QDs of the same size and surface

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

• shows a CdTe deposition with and without UV illumination. We further note that the nanocrystal luminescence under ambient conditions is preserved. X-ray diffraction analysis The structural properties of the prepared samples were evaluated by XRD and Raman spectroscopy, using CdTe thin films deposited on

• lower than 2.4 mmol, impurity-free CdTe colloids were obtained. Optical characterization According to Figure 2, our CdTe colloids display a strong red luminescence, indicating quantum confinement in the nanosized CdTe crystals. It is known that quantum confinement can be observed for crystallite sizes

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• carriers, quantum dots have a unique photoluminescence (PL). In comparison with organic dyes, quantum dots are characterized by unique optical and electronic properties such as a higher PL quantum efficiency, a wide continuous absorption, a narrower PL band, tunable luminescence depending only on their

• semiconductor can change into a direct bandgap. Correspondingly, the monolayer of MoS2 exhibits 104 times enhancement of luminescence quantum efficiency than that of bulk material. This new finding has also been verified by other research groups [149][150]. Based on this new finding, one may easily imagine that

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

• Jinzhang Liu,
• Marco Notarianni,
• Llew Rintoul and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 485–493, doi:10.3762/bjnano.5.56

• –matter interaction within those crystals, the luminescence of the cavity material has been conventionally used as a light source. Under excitation, ZnO emits UV light at about 380 nm ascribed to its wide band gap (Eg ≈ 3.4 eV). With crystal defects such as oxygen vacancies, ZnO show visible

• photoluminescence under UV light excitation. Though ZnO micro/nanorods can be both light emitters and optical cavities, the drawback is that their luminescence is not tunable in terms of wavelength and efficiency. For laser applications, the visible emission of ZnO micro/nanocavities has a broad range which can be

• , ruling out the influence of ZnO luminescence in causing the shift of NDs emission. In Figure 6b, the PL spectrum of NDs in a thick ZnO microrod shows a different shape compared to that of naked NDs. The inset in Figure 6b is an optical microscope image, in which the relatively thick rod marked by a cross

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

• colloidal solutions with good luminescence properties are obtained by using PVP as stabilizer in the synthesis of ZnO nanoparticles by a sol–gel method assisted by ultrasound. Nanoparticles with sizes of 30–40 nm in a PVP matrix are produced as a solid product. The colloidal ZnO/PVP/methanol solution, apart

• (PL) spectra of the ZnO nanoparticles in methanol were measured at room temperature with an MDR-23 spectrometer. The samples were excited by a nitrogen laser with wavelength of 337.1 nm. Results and Discussion The image of a cell with ZnO colloidal solution is shown in Figure 1. A bright luminescence

• -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

One pot synthesis of silver nanoparticles using a cyclodextrin containing polymer as reductant and stabilizer

• Arkadius Maciollek and
• Helmut Ritter

Beilstein J. Nanotechnol. 2014, 5, 380–385, doi:10.3762/bjnano.5.44

• –visible spectrophotometer equipped with a Thermo Scientific CD10 Heating Circulator bath. Fluorescence spectra were recorded on a Perkin Elmer LS55 luminescence spectrometer. Zeta Potential and dynamic light scattering (DLS) experiments were carried out with a Malvern Zetasizer Nano; ZS ZEN 3600 at a

Photoactivation of luminescence in CdS nanocrystals

• Valentyn Smyntyna,
• Bogdan Semenenko,
• Valentyna Skobeeva and
• Nikolay Malushin

Beilstein J. Nanotechnol. 2014, 5, 355–359, doi:10.3762/bjnano.5.40

• Valentyn Smyntyna Bogdan Semenenko Valentyna Skobeeva Nikolay Malushin Experimental Physics Department Odessa; I.I. Mechnikov National University; 2, Dvoryanska St., Odessa, UA-65026, Ukraine 10.3762/bjnano.5.40 Abstract This paper presents the results of the research on the luminescence of

• the surface of NC. The observed effect is explained by the recombination mechanism that is responsible for the short-wavelength emission band. Keywords: cadmium sulfide (CdS); luminescence; nanoparticles; short-wavelength emission band; surface modification; Introduction Semiconductor nanocrystals

• spectrum. For that reason these materials are commonly used as luminophores in light emitting devices. A variety of luminescence colors can be produced from the same material by controlling the size of the nanocrystals. An important property of crystals that have a size in the nanometer-range and are

Energy transfer in complexes of water-soluble quantum dots and chlorin e6 molecules in different environments

• Irina V. Martynenko,
• Anna O. Orlova,
• Vladimir G. Maslov,
• Alexander V. Baranov,
• Anatoly V. Fedorov and
• Mikhail Artemyev

Beilstein J. Nanotechnol. 2013, 4, 895–902, doi:10.3762/bjnano.4.101

• of Ce6 is located and the QD absorption is relatively small, was used. Time resolved luminescence measurements were performed with a laser scanning luminescent microscope, Micro Time 100 (Pico Quant), that allows registration of the luminescence decay in the 430–850 nm spectral range with 100 ps time

• , normalized to the Ce6 optical density at excitation wavelength, is ≈1.5 times higher for 475 nm excitation than for the 640 nm one that indicates a presence of sensibilized Ce6 luminescence. These facts show intracomplex FRET from QD to Ce6. For this system, the energy transfer efficiency of 8%, calculated

• and their tendency to dissociation, they are supposed to be good model objects to explore the dependencies of FRET efficiency and Ce6 QY on n in the complexes by spectral luminescence methods. The samples for studies were prepared by stepwise increasing the Ce6 concentration in solution of QD and Ce6

Modulation of defect-mediated energy transfer from ZnO nanoparticles for the photocatalytic degradation of bilirubin

• Tanujjal Bora,
• Karthik K. Lakshman,
• Soumik Sarkar,
• Abhinandan Makhal,
• Samim Sardar,
• Samir K. Pal and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2013, 4, 714–725, doi:10.3762/bjnano.4.81

• ]. It has been reported that the native defects in the ZnO lattice, mostly the oxygen vacancy sites, play an important role in the photocatalytic activity of the nanostructures [11]. Oxygen vacancies have been reported as the cause of the characteristic green luminescence of ZnO [12][13][14]. These

• deep-level trap state (VO++) as the origin of the green luminescence. Whereas Vanheusden et al. [29] reported that the recombination of an electron from a VO+ state to a valence band hole lead to the green luminescence peak. In contrast, J. D. Ye et al. [27] has reported that both the above assumptions

• are correct and demonstrated that the broad green–yellow luminescence from ZnO is mainly composed of two individual emission bands centered at approx. 520 and approx. 590 nm respectively, as shown in Figure 3b. It was observed that with increasing annealing temperature the green–yellow emission from

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

• 1 nm steps over the 300–1100 nm range, and photoluminescence in the 370–800 nm range. A solid state LCS-DTL-374QT Nd:YAG 355 nm laser source (Russia) at the intensity of 19 mW/cm2 was used to excite the luminescence. Emission spectra were registered by the experimental setup described by Viter et al

Near-field effects and energy transfer in hybrid metal-oxide nanostructures

• Ulrich Herr,
• Barat Achinuq,
• Cahit Benel,
• Giorgos Papageorgiou,
• Manuel Goncalves,
• Johannes Boneberg,
• Paul Leiderer,
• Paul Ziemann,
• Peter Marek and
• Horst Hahn

Beilstein J. Nanotechnol. 2013, 4, 306–317, doi:10.3762/bjnano.4.34

• Eu fluorescence can be suppressed by covering the nanoantennas with a 10 nm thick SiOx layer. Keywords: confocal microscopy; energy transfer; field enhancement; light harvesting; luminescence; nano-antennas; nanosphere lithography; nanostructures; plasmonics; simulation; TiO2 nanoparticles