Templated green synthesis of plasmonic silver nanoparticles in onion epidermal cells suitable for surface-enhanced Raman and hyper-Raman scattering

• Marta Espina Palanco,
• Klaus Bo Mogensen,
• Marina Gühlke,
• Zsuzsanna Heiner,
• Janina Kneipp and
• Katrin Kneipp

Beilstein J. Nanotechnol. 2016, 7, 834–840, doi:10.3762/bjnano.7.75

• space they surround provide a biological template for the growth process of plasmonic silver structures. In our experimental study, we exploit luminescence spectroscopy and dark-field microscopy for probing the formation of metal nanostructures in situ in the onion tissue. Local optical fields related

• -Aldrich Denmark A/S) instead of AgNO3. Luminescence measurements and dark-field microscopy Luminescence spectra and images were measured through a 100× oil immersion objective (Leica DMLM microscope) using a laser diode (473 nm, ca. 20 mW) for excitation and equipped with a λ = 520 nm long-wave pass

• to AgNO3 solution, and a following drying period of 2–3 h, the onion samples appear in a reddish color, compared to their initial whitish color, suggesting the formation of nanoparticles. Additionally, Figure 1 shows a strong luminescence signal in yellow-greenish colors emitted from the onion layers

Facile synthesis of water-soluble carbon nano-onions under alkaline conditions

• Gaber Hashem Gaber Ahmed,
• Rosana Badía Laíño,
• Josefa Angela García Calzón and
• Marta Elena Díaz García

Beilstein J. Nanotechnol. 2016, 7, 758–766, doi:10.3762/bjnano.7.67

• measurement The PL quantum yield was calculated through the well-established comparative method using quinine sulfate as a reference. The following equations were used in the quantum yield measurement: where is the quantum yield, F is the calculated integrated luminescence intensity, n is the refractive

Highly compact refractive index sensor based on stripe waveguides for lab-on-a-chip sensing applications

• Chamanei Perera,
• Kristy Vernon,
• Elliot Cheng,
• Juna Sathian,
• Esa Jaatinen and
• Timothy Davis

Beilstein J. Nanotechnol. 2016, 7, 751–757, doi:10.3762/bjnano.7.66

• quantum dots (QDs) with emission wavelength at 655 nm (from Invitrogen Cat. No. Q21321MP). An optimum QD spacer layer thickness of 18 nm SiO2 was selected [23]. The sensor designs with separations between two outer arms of 300 nm (Figure 4a) and 200 nm (Figure 4b) were observed under QD luminescence. We

• of 633 nm. These simulations were done using COMSOL Multiphysics. SEM images of interferometers with gap separation a) 200 nm and b) 300 nm. The scale bar in the figure represents 10 µm. QD luminescence images of interferometers with 300 nm gap and 200 nm gap when excited via input arm with a 633 nm

Hierarchical coassembly of DNA–triptycene hybrid molecular building blocks and zinc protoporphyrin IX

• Rina Kumari,
• Sumit Singh,
• Mohan Monisha,
• Sourav Bhowmick,
• Anindya Roy,
• Neeladri Das and
• Prolay Das

Beilstein J. Nanotechnol. 2016, 7, 697–707, doi:10.3762/bjnano.7.62

• the orientation of the DNA strands relative to one another in a programmed manner [21][36][37][38][39]. The diverse structural features and functionalities of the organic core such as luminescence, redox, magnetic, and catalytic properties play a vital role in enhancing the versatility of the discrete

Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles

• Julia A. Burunkova,
• Ihor Yu. Denisiuk,
• Dmitri I. Zhuk,
• Lajos Daroczi,
• Attila Csik,
• István Csarnovics and
• Sándor Kokenyesi

Beilstein J. Nanotechnol. 2016, 7, 630–636, doi:10.3762/bjnano.7.55

• , suitable for direct, light-induced formation of photonic elements. Introduction of preformed gold nanoparticles in such a nanocomposite was also performed and an enhancement of luminescence due to the influence of plasmon effects was detected. Keywords: gold nanoparticles; luminescence; optical materials

• results in large, i.e., tens of nanometers, REO particles. At the same time it is important to avoid the high level of light scattering in a composite with a rather high concentration of RE ions nanoparticles and to assure a high luminescence output. The simple increase of the concentration of small

• nanoparticles is not always a good solution to the problem because of the possible decrease of luminescence intensity due to the counterproductive introduction of energy-transfer processes at high concentrations of rare earth ions. For example, as it was shown in [5] for Er-doped silicon materials, a practical

Dependence of lattice strain relaxation, absorbance, and sheet resistance on thickness in textured ZnO@B transparent conductive oxide for thin-film solar cell applications

• Kuang-Yang Kou,
• Yu-En Huang,
• Chien-Hsun Chen and
• Shih-Wei Feng

Beilstein J. Nanotechnol. 2016, 7, 75–80, doi:10.3762/bjnano.7.9

• ]. The variation in the physical properties of nanostructures drastically influences the optoelectronic properties of ZnO [11][12][13]. X-ray-excited optical luminescence of ZnO nanoneedles shows a sharp band gap emission and a broad red emission related to surface defects, while that of ZnO

Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties

• Uliana Kostiv,
• Miroslav Šlouf,
• Hana Macková,
• Alexander Zhigunov,
• Hana Engstová,
• Katarína Smolková,
• Petr Ježek and
• Daniel Horák

Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235

• :Yb3+/Er3+ nanoparticles at temperatures above 300 °C was confirmed by both ED and XRD. Upconversion luminescence under excitation at 980 nm was observed in the luminescence spectra of OM–NaYF4:Yb3+/Er3+ nanoparticles. Finally, the OM–NaYF4:Yb3+/Er3+ nanoparticles were coated with a silica shell to

• functionalization and biocompatibility [27]. We herein report the preparation of OM–NaYF4:Yb3+/Er3+ nanoparticles with controlled morphology, size, composition, phase and luminescence. Thorough particle characterization was performed to elucidate the relationship between synthetic conditions and particle structure

• ATR correction was applied. Upconversion luminescence spectra were recorded on a Leica TCS SP2 AOBS confocal inverted fluorescent microscope (Leica Microsystems; Mannheim, Germany) using a PL APO 100×/1.40–0.70 oil immersion objective (a pinhole 1 Airy unit) and a Chameleon laser Ultra Ti:sapphire

A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials

• Daniela Lehr,
• Markus R. Wagner,
• Johanna Flock,
• Julian S. Reparaz,
• Clivia M. Sotomayor Torres,
• Alexander Klaiber,
• Thomas Dekorsy and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2015, 6, 2161–2172, doi:10.3762/bjnano.6.222

• recorded at room temperature (Figure 4c). Furthermore, Cl doping strongly affects the so-called green luminescence, which is associated with electrons trapped at oxygen vacancies (VO•• in Kröger–Vink notation) present in many different types of ZnO materials [63]. It can be seen that the intensity of the

• green luminescence (normalized to the near band-edge emission) gradually decreases with increasing amount of chlorine (Figure 4b). The latter observation might be explained as follows. Substitution of O2− by Cl− leads to an excess of positive charges in the lattice (ClO•). Thus, point defects that also

• lead to relative positive charges such as VO•• become more and more unfavorable and the green luminescence is suppressed. The low-temperature photoluminescence spectra measured at 7 K (Figure 4d) provide detailed information about the near band-edge luminescence. The spectrum of the undoped ZnO sample

Light-powered, artificial molecular pumps: a minimalistic approach

• Giulio Ragazzon,
• Massimo Baroncini,
• Serena Silvi,
• Margherita Venturi and
• Alberto Credi

Beilstein J. Nanotechnol. 2015, 6, 2096–2104, doi:10.3762/bjnano.6.214

• the system so that the directional transit could be caused solely by light irradiation [18]. To this aim, the benzene units of macrocycle 2 were replaced with naphthalene ones (ring 3, Figure 4). Such naphthalene units are strongly fluorescent and thus enable the use of luminescence spectroscopy (a

Mapping bound plasmon propagation on a nanoscale stripe waveguide using quantum dots: influence of spacer layer thickness

• Chamanei S. Perera,
• Alison M. Funston,
• Han-Hao Cheng and
• Kristy C. Vernon

Beilstein J. Nanotechnol. 2015, 6, 2046–2051, doi:10.3762/bjnano.6.208

• homogeneous QD layer (with a spacer layer of thickness 20 nm), we observed the bright luminescence around the waveguide rapidly decaying along the waveguide length (Figure 6b). If the frequency of the plasmons propagating on the stripe lies within the broad absorption band of the QDs, QDs in the immediate

• has an increased PL intensity when excited using a TM polarised laser. This increase in the DoP is an evidence that plasmons are causing the near-waveguide luminescence and QDs near the waveguide are excited by the propagating surface plasmons on the waveguide. PL of the QDs can be quenched due to non

NanoE-Tox: New and in-depth database concerning ecotoxicity of nanomaterials

• Katre Juganson,
• Angela Ivask,
• Irina Blinova,
• Monika Mortimer and
• Anne Kahru

Beilstein J. Nanotechnol. 2015, 6, 1788–1804, doi:10.3762/bjnano.6.183

• endpoints used The toxicity values for ENMs, irrespective of the endpoint, were based on nominal concentrations of ENMs. As expected, in most of the studies (77% of the entries) the toxicological endpoint was viability (e.g., mortality, immobilisation, growth inhibition, luminescence/fluorescence inhibition

Nonlinear optical properties of near-infrared region Ag₂S quantum dots pumped by nanosecond laser pulses

• Li-wei Liu,
• Si-yi Hu,
• Yin-ping Dou,
• Tian-hang Liu,
• Jing-quan Lin and
• Yue Wang

Beilstein J. Nanotechnol. 2015, 6, 1781–1787, doi:10.3762/bjnano.6.182

• fluorescence lifetimes, high quantum yields, and luminescence emission with large Stokes shift [2]. The development of synthetic nanoparticles has facilitated research on the nonlinear behavior of QDs and shown the great potential of QDs for different applications [3][4]. The synthesis of QDs with nonlinear

A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe₃O₄ magnetic and fluorescent nanocrystals

• Houcine Labiadh,
• Tahar Ben Chaabane,
• Romain Sibille,
• Lavinia Balan and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2015, 6, 1743–1751, doi:10.3762/bjnano.6.178

• luminescence efficiency, and vice versa. The Mn:ZnS/ZnS/Fe3O4 (1) sample, which exhibited the best fluorescence quantum yield, also exhibited limited magnetic characteristics. Nevertheless, samples Mn:ZnS/ZnS/Fe3O4 (1.5) and Mn:ZnS/ZnS/Fe3O4 (2) are a good compromise to maintain both fluorescence and magnetic

Addition of Zn during the phosphine-based synthesis of indium phospide quantum dots: doping and surface passivation

• Natalia E. Mordvinova,
• Alexander A. Vinokurov,
• Oleg I. Lebedev,
• Tatiana A. Kuznetsova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2015, 6, 1237–1246, doi:10.3762/bjnano.6.127

• obtained quantum dots. We propose a mechanism for the introduction of Zn in the QDs and show that the incorporation of Zn atoms into the InP lattice leads to the formation of Zn acceptor levels and a luminescence tail in the red region of the spectra. Using photochemical etching with HF, we confirmed that

• luminescence quantum yield through the reduction of phosphorous dangling bonds. A scenario for the growth of the colloidal InP(Zn) QDs was proposed and discussed. Keywords: core–shell nanoparticles; doped semiconductor nanocrystals; InP(Zn) quantum dots; luminescence; zinc; Introduction Colloidal quantum

• –V materials InP colloidal QDs have gained the most attention due to their stability and the most intensive luminescence in the visible and near-IR spectral regions. There are several synthetic approaches to obtain InP QDs [6][7][8][9][10]. One of the most commonly used methods nowadays includes the

Charge carrier mobility and electronic properties of Al(Op)₃: impact of excimer formation

• Andrea Magri,
• Pascal Friederich,
• Bernhard Schäfer,
• Valeria Fattori,
• Xiangnan Sun,
• Timo Strunk,
• Velimir Meded,
• Luis E. Hueso,
• Wolfgang Wenzel and
• Mario Ruben

Beilstein J. Nanotechnol. 2015, 6, 1107–1115, doi:10.3762/bjnano.6.112

• considerably lower, 0.014, and the lifetime (τ) is an order of magnitude longer, 7.1 ns. The lifetimes were calculated by the luminescence decays, in solution and in the thin film, as shown in Figure 4. Field effect mobility in TFT devices From the electrical characteristics measured in a field-effect

• emission spectra were recorded with an excitation wavelength of 350 nm. The excimer formation is clearly noticeable from the difference in the emission peaks in solution and in the thin film. Photographs of the samples under UV irradiation are included to show the visible color change. Luminescence decay

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

• Kai Braun,
• Xiao Wang,
• Andreas M. Kern,
• Hilmar Adler,
• Heiko Peisert,
• Thomas Chassé,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2015, 6, 1100–1106, doi:10.3762/bjnano.6.111

• resolution [3]. For pure metal surfaces [4][5] or organic monolayers adsorbed directly on a metal surface [6], the emission of light originates predominantly from the radiative decay of localized surface plasmons (LSP) excited by inelastic electron tunneling (IET) as the direct luminescence of the molecules

• is quenched. If the molecules are decoupled from the metal surface by an ultrathin dielectric spacer, intrinsic molecular luminescence can be observed down to the single-molecule level [7], showing vibronic bands [8][9]. Very recently electroluminescence from a conducting molecule, bridging the gap

• scattering (TERS) [11][12] or gap mode near-field optical microscopy [13]. This technique has attracted great interest as a means for local Raman [14][15] or luminescence spectroscopy [16] with nanometer spatial resolution. Since efficient Raman scattering from molecules in the gap requires gap widths as

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

• Desiré M. De los Santos,
• Javier Navas,
• Teresa Aguilar,
• Antonio Sánchez-Coronilla,
• Concha Fernández-Lorenzo,
• Rodrigo Alcántara,
• Jose Carlos Piñero,
• Ginesa Blanco and
• Joaquín Martín-Calleja

Beilstein J. Nanotechnol. 2015, 6, 605–616, doi:10.3762/bjnano.6.62

• . This band is energetically very close to the excitation source used in Raman spectroscopy (785 nm). The luminescence phenomena associated with Tm3+are well-documented [20][23][36][40][41]. At this excitation wavelength, it is assumed that photon absorption occurs, which then results in the luminescence

• processes. The 3H4 excited state is accessible with this laser excitation (see UV–vis results), and electrons in this state can transition to the lower levels of the 3H6 ground state, generating luminescence. The shape of the resulting Raman signal is typical of luminescence processes: a very wide band (in

• contrast to the sharp, characteristic, Raman bands) is observed. When the electronic transition that generates the luminescence process takes place between two triplet states, absorption (and thus the relaxation in luminescence) processes are permitted, and intense signals are generated. This can be

Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

• Shanka Walia and
• Amitabha Acharya

Beilstein J. Nanotechnol. 2015, 6, 546–558, doi:10.3762/bjnano.6.57

• electronic transitions involved are of the type 4fn→4fn−15d1, which accounts for their strong luminescence spectra. Further the high magnetic moment of the lanthanide complexes can be attributed to the spin–orbit coupling of the 4f electrons. Hence, the lanthanides complexes are fluorescent as well as

Tunable white light emission by variation of composition and defects of electrospun Al₂O₃–SiO₂ nanofibers

• Jinyuan Zhou,
• Gengzhi Sun,
• Hao Zhao,
• Xiaojun Pan,
• Zhenxing Zhang,
• Yujun Fu,
• Yanzhe Mao and
• Erqing Xie

Beilstein J. Nanotechnol. 2015, 6, 313–320, doi:10.3762/bjnano.6.29

• defects, green emission from ≡Si(Al)–O–C∙=O, and red emission from intersystem radiative crossing. White light emission was realized at a Al/(Al–Si) ratio of 40 and 60 mol %. This research may offer a deeper understanding of the preparation of efficient and environmentally friendly, white luminescence

• wavelengths, allowing for potential application in white light emission devices. It has been demonstrated that the luminescence emission and emission intensity of SiO2 nanostructures are strongly dependent upon the intrinsic structural defects and extrinsic environmental influences introduced during the

• assigned to OH-related radiative emission centers formed in the samples [11]. Additionally, Yoldas also showed that the A12O3–SiO2 composites respond to UV light by emission of strong, visible luminescence (400–700 nm), which is due to the (≡Si–O¨O–Si≡) radiative centers [17]. Chen et al. reported a peapod

Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization

• Lisa Landgraf,
• Ines Müller,
• Peter Ernst,
• Miriam Schäfer,
• Christina Rosman,
• Isabel Schick,
• Oskar Köhler,
• Hartmut Oehring,
• Vladimir V. Breus,
• Thomas Basché,
• Carsten Sönnichsen,
• Wolfgang Tremel and
• Ingrid Hilger

Beilstein J. Nanotechnol. 2015, 6, 300–312, doi:10.3762/bjnano.6.28

• used a colorimetric (MTS: 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; Aqueous One Solution Cell Proliferation Assay, Promega, Germany) and a luminescence (ATPLite assay, PerkinElmer, Germany) based cytotoxicity assay. In this context, cells were

• , Germany) after a 4 h incubation period at 37 °C. The production of light was measured with a luminescence plate reader (BMG LABATECH GmbH, Germany). Relative cellular dehydrogenase and ATP levels were expressed as relative values to the untreated control. Measuring cell viability through impedance

Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

• Jes Ærøe Hyllested,
• Marta Espina Palanco,
• Nicolai Hagen,
• Klaus Bo Mogensen and
• Katrin Kneipp

Beilstein J. Nanotechnol. 2015, 6, 293–299, doi:10.3762/bjnano.6.27

• excitation. Keywords: fruits; green synthesis; luminescence; plants; plasmonics; SERS; silver cluster; silver nanoparticles; Introduction Metal nanoparticles in various size ranges play an increasingly important role in many different fields of science, technology and medicine ranging from applications as

• increase of the characteristic surface plasmon absorption around 420–470 nm and shifts of the absorption peak, respectively. Absorption signatures in the UV range which can be assigned to small silver clusters and surface enhanced luminescence spectra collected from the particles can provide information on

• 270 nm related to Ag42+ confirming the conversion of silver clusters to plasmonic silver nanoparticles. A strong luminescence signal in bright colors emitted from small silver clusters is a very interesting finding [26][27]. As it is shown in Figure 6, the presence of various silver clusters on the

Functionalization of α-synuclein fibrils

• Simona Povilonienė,
• Vida Časaitė,
• Virginijus Bukauskas,
• Arūnas Šetkus,
• Juozas Staniulis and
• Rolandas Meškys

Beilstein J. Nanotechnol. 2015, 6, 124–133, doi:10.3762/bjnano.6.12

• solution (calculated from the initial concentration of protein prior to fibrillization) and incubated for 10 minutes at room temperature. Fluorescence emission spectra of ThT, excited at 450 nm, were recorded between 460 and 600 nm on a PerkinElmer LS55 luminescence spectrometer using excitation and

Synthesis of boron nitride nanotubes and their applications

• Saban Kalay,
• Zehra Yilmaz,
• Ozlem Sen,
• Melis Emanet,
• Emine Kazanc and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 84–102, doi:10.3762/bjnano.6.9

• luminescence properties and good dispersibility in organic solvents [7]. The BNNTs were also coated with PEGylated phospholipid 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(poly(ethylene glycol))] conjugates (mPEG–DSPE)] [17]. This polymer was selected due to its water solubility and

Size-dependent density of zirconia nanoparticles

• Agnieszka Opalinska,
• Iwona Malka,
• Wojciech Dzwolak,
• Tadeusz Chudoba,
• Adam Presz and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2015, 6, 27–35, doi:10.3762/bjnano.6.4

• as a luminescent material, the luminescence intensity increases with crystallite size [17]. The size and surface properties of NPs are also important for toxicology and health applications. The size of the NPs can influence their distribution in the human body and the mechanism of their penetration

• as their chemical reactivity and hydrophilic properties. The hydroxy groups on the NP surface can also operate as effective adsorption sites for organic substances from the atmosphere [23]. Grave and colleagues attributed the increase of the nanopowder luminescence intensity with gain growth to the

Bright photoluminescence from ordered arrays of SiGe nanowires grown on Si(111)

• D. J. Lockwood,
• N. L. Rowell,
• A. Benkouider,
• A. Ronda,
• L. Favre and
• I. Berbezier

Beilstein J. Nanotechnol. 2014, 5, 2498–2504, doi:10.3762/bjnano.5.259

• from the substrate. They are not strained to any significant extent and x for these samples is confirmed from the PL to be 0.15. These NWs with their well-controlled position, composition, and size and their efficient luminescence exhibit relevant features that are a significant improvement in quality