Colloidal solution of silver nanoparticles for label-free colorimetric sensing of ammonia in aqueous solutions

• Alessandro Buccolieri,
• Antonio Serra,
• Gabriele Giancane and
• Daniela Manno

Beilstein J. Nanotechnol. 2018, 9, 499–507, doi:10.3762/bjnano.9.48

• (NH3) in the concentration range from 10−2 to 103 ppm to develop an optical sensor for NH3 in aqueous solutions. Ammonia affects the features of the nanoparticles obtained in a concentration-dependent manner as determined by UV–vis absorption analysis and TEM observations. Structural and morphological

• nanoparticles, we show in Figure 1 the UV–vis absorption spectra obtained from the most representative samples. The peak at about 400 nm is due to SPR of the electrons in the conduction band of silver and indicates the formation of silver colloids with nanometre-sized dimensions. Ammonia modulates the UV–vis

• particular, the results were interpreted by a first-order kinetic model [30][31]. As expected, the final result depends on NH3 concentration and on reaction time. Figure 6 shows the time evolution of UV–vis absorption spectra of two different colloidal solutions containing 200 ppm and 5 ppm ammonia (Figure

Sugarcane juice derived carbon dot–graphitic carbon nitride composites for bisphenol A degradation under sunlight irradiation

• Lan Ching Sim,
• Jing Lin Wong,
• Chen Hong Hak,
• Jun Yan Tai,
• Kah Hon Leong and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2018, 9, 353–363, doi:10.3762/bjnano.9.35

• content. Optical properties Figure 3a shows the UV–vis absorption spectra of CDs in an aqueous solution in the range from 200 nm to 750 nm. The obvious peak at about 330 nm could be ascribed to the n–π* transition of C=O bond [56]. The inset of Figure 3a shows that the CD solution emitted a strong blue

Synthesis and characterization of electrospun molybdenum dioxide–carbon nanofibers as sulfur matrix additives for rechargeable lithium–sulfur battery applications

• Ruiyuan Zhuang,
• Shanshan Yao,
• Maoxiang Jing,
• Xiangqian Shen,
• Jun Xiang,
• Tianbao Li,
• Kesong Xiao and
• Shibiao Qin

Beilstein J. Nanotechnol. 2018, 9, 262–270, doi:10.3762/bjnano.9.28

• composite. (c) Optical photo of Li2S6 adsorption on MoO2–CNFs and (d) UV–vis absorption spectra of the Li2S6 solution before and after the addition of MoO2–CNFs. (a) The CV curves of cells assembled with S/MoO2–CNF cathodes and pure sulfur cathodes. (b) Cycling performance of MoO2–CNFs calcined at different

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

• Jiajun Wang,
• Xia Liu,
• Gesmi Milcovich,
• Tzu-Yu Chen,
• Edel Durack,
• Sarah Mallen,
• Yongming Ruan,
• Xuexiang Weng and
• Sarah P. Hudson

Beilstein J. Nanotechnol. 2018, 9, 137–145, doi:10.3762/bjnano.9.16

• sp2-bonded carbon atoms [36], which agrees well with the proposed co-reduction pathway to effectively produce more reduced carbon with a higher C-dot QY. UV–vis absorption and fluorescence properties were studied at room temperature to explore the optical properties of the three optimized C-dots. As

• spectroscopy (XPS), using a K-Alpha XPS spectrometer (Scientific Escalab 250) with an Al Kα X-ray radiation (1486.6 eV) source for excitation. UV–vis absorption spectra of the samples were recorded on a Perkin Elmer Lambda 950 spectrophotometer. FT-IR was conducted at room temperature on a Nicolet 670

• –vis absorption, excitation and emission spectra, (D–F) fluorescence emission spectra recorded at different excitation wavelengths and (G–I) fluorescence intensity decay curves of Sa, Sb and Se, respectively. Fourier transform infrared spectra of Sa, Sb, and Se. XPS spectra of Sa, Sb, and Se. (A) full

Facile synthesis of silver/silver thiocyanate (Ag@AgSCN) plasmonic nanostructures with enhanced photocatalytic performance

• Xinfu Zhao,
• Dairong Chen,
• Abdul Qayum,
• Bo Chen and
• Xiuling Jiao

Beilstein J. Nanotechnol. 2017, 8, 2781–2789, doi:10.3762/bjnano.8.277

• taken every 10 min and centrifuged to remove the dispersed photocatalyst, and the supernatant was transferred to a quartz cuvette to measure the UV–vis absorption spectrum. The concentration change of oxytetracycline was monitored according to its maximum absorbance at 364 nm (λmax) recorded by a Perkin

• experimental data. The Supporting Information contains details of the AgSCN characterization, Nyquist plots, EDS spectrum of different Ag/AgSCN samples, and UV–vis absorption spectra of oxytetracycline solutions with M2 as a catalyst. Acknowledgements This work is supported by the National Natural Science

CdSe nanorod/TiO₂ nanoparticle heterojunctions with enhanced solar- and visible-light photocatalytic activity

• Fakher Laatar,
• Hatem Moussa,
• Halima Alem,
• Lavinia Balan,
• Emilien Girot,
• Ghouti Medjahdi,
• Hatem Ezzaouia and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 2741–2752, doi:10.3762/bjnano.8.273

• discolored during photocatalytic experiments (Figure 6c) and the dye was also partially decomposed (the TOC value decreased from 6.9 ± 0.3 to 2.4 ± 0.2 mg/L after the 150 min of irradiation). The temporal evolution of the UV–vis absorption spectra is displayed in Figure 6b. The intensity of the RhB

PTFE-based microreactor system for the continuous synthesis of full-visible-spectrum emitting cesium lead halide perovskite nanocrystals

• Chengxi Zhang,
• Weiling Luan,
• Yuhang Yin and
• Fuqian Yang

Beilstein J. Nanotechnol. 2017, 8, 2521–2529, doi:10.3762/bjnano.8.252

• nanocrystals have a mostly rod-like shape is ≈120 °C. For the reaction temperature of 160 °C, the color and shape of the formed CsPbBr3 QDs are green and cubic, respectively. Such results demonstrate the morphological dependence of the QDs on the reaction temperature in the PTFE-based microsystem. UV–vis

• absorption was used to analyze the optical characteristics of the CsPbX3 QD solutions exhibiting a blue, green, yellow, orange and red color (see Figure S3 in Supporting Information File 1). The maximum UV absorption wavelengths are 475 nm (2.61 eV), 523 nm (2.37 eV), 520 nm (2.38 eV), 600 nm (2.07 eV), and

Hydrothermal synthesis of ZnO quantum dot/KNb₃O₈ nanosheet photocatalysts for reducing carbon dioxide to methanol

• Xiao Shao,
• Weiyue Xin and
• Xiaohong Yin

Beilstein J. Nanotechnol. 2017, 8, 2264–2270, doi:10.3762/bjnano.8.226

• . The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UV–vis absorption spectroscopy (UV–vis). The photocatalytic activity of the

Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites

• Claudio Larosa,
• Niranjan Patra,
• Marco Salerno,
• Lara Mikac,
• Remo Merijs Meri and
• Mile Ivanda

Beilstein J. Nanotechnol. 2017, 8, 2026–2031, doi:10.3762/bjnano.8.203

• presence of submicrometer-scale filler particles throughout the polymer matrix is also observed even at the highest MWCNT loading (see Figure 1d). UV–vis absorption spectra of the PC/MWCNT composite films are presented in Figure 2. Good dispersion is crucial for optimal optical properties and ensures

Fabrication of carbon nanospheres by the pyrolysis of polyacrylonitrile–poly(methyl methacrylate) core–shell composite nanoparticles

• Dafu Wei,
• Youwei Zhang and
• Jinping Fu

Beilstein J. Nanotechnol. 2017, 8, 1897–1908, doi:10.3762/bjnano.8.190

• (BJH) method. UV–vis absorption spectra were performed on a Perkin Elmer Lambda 25 spectrophotometer. Results and Discussion PAN–PMMA nanoparticles To realize the efficient and controlled fabrication of PAN-based carbon nanospheres from a PAN–PMMA nanoparticle precursor via the pyrolysis method, one

(Metallo)porphyrins for potential materials science applications

• Lars Smykalla,
• Carola Mende,
• Michael Fronk,
• Pablo F. Siles,
• Michael Hietschold,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1786–1800, doi:10.3762/bjnano.8.180

• the spectral range of the Q band. In the case of H2TPP(OMe)4 the MCD spectrum in Figure 6a shows only one B-term pair. The energies of the two features of opposite sign correspond to the first and third absorption peak of the UV–vis absorption spectrum. According to [14] the observation of a B-term

Methionine-mediated synthesis of magnetic nanoparticles and functionalization with gold quantum dots for theranostic applications

• Arūnas Jagminas,
• Agnė Mikalauskaitė,
• Vitalijus Karabanovas and
• Jūrate Vaičiūnienė

Beilstein J. Nanotechnol. 2017, 8, 1734–1741, doi:10.3762/bjnano.8.174

• . Typical UV–vis absorption spectra of aqueous methionine, tetrachlorauric acid and gold species solution are shown in Figure 3. The pure methionine solution does not exhibit any absorption peaks in the measured spectral range. For the chloroauric acid solution, however, a clearly resolved absorption peak

• at 291 nm is observed. The UV–vis absorption spectrum of the solution containing the gold species collected from the surface of the cobalt ferrite NPs (Figure 3, plot 3) exhibits two absorption shoulders at 522 and 377 nm. The former seems to be originated from the surface plasmon absorption of

Bright fluorescent silica-nanoparticle probes for high-resolution STED and confocal microscopy

• Isabella Tavernaro,
• Christian Cavelius,
• Henrike Peuschel and
• Annette Kraegeloh

Beilstein J. Nanotechnol. 2017, 8, 1283–1296, doi:10.3762/bjnano.8.130

• nanoparticles were performed. First of all, we studied the influence of the integration of the dyes into the silica matrix on the absorption and fluorescence signal. Comparison of the UV–vis absorption and fluorescence spectra of dye-doped silica nanoparticles and those of free dye molecules indicated no

• silica nanoparticles and the free dye molecules indicate a nearly similar maximum at 660 nm. Identical results were obtained for the comparison of the free other dyes with the embedded ones (data not shown). Also a comparison of the UV–vis absorption and fluorescence spectra of the synthesised dye

Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

• Rasha K. Al-Shewiki,
• Carola Mende,
• Roy Buschbeck,
• Pablo F. Siles,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1191–1204, doi:10.3762/bjnano.8.121

• terminal –C(O)NR2 groups. UV–vis studies The UV–vis absorption spectra of 2/2a–d and 3/3a–d were recorded in CHCl3 solution in the spectral range of 230–700 nm. In order to avoid possible impact of the concentrations on λabs and ε, which was reported for (metallo)phthalocyanines [28], we performed

• , which appear different in intensity from spectra to spectra, are due to CO2.) C, H, N elemental analyses were performed using a Thermo FlashAE 1112 series analyzer. High-resolution mass spectra were recorded with a Bruker micrOTOF QII equipped with an Apollo II ESI source. UV–vis absorption spectra were

• H2TPP(OH)4. Synthetic methodology to prepare (metallo)porphyrins 2, 2a–d and 3, 3a–d. Wavenumbers of numbered IR vibrations of 2/2a–d and 3/3a–d in the range from 500–1800 cm−1.a Wavelengths of UV–vis absorption bands of 2/2a–d and 3/3a–d in the range of 280–700 nm.a Supporting Information Supporting

Surface-enhanced Raman spectroscopy of cell lysates mixed with silver nanoparticles for tumor classification

• Mohamed Hassoun,
• Iwan W.Schie,
• Tatiana Tolstik,
• Sarmiza E. Stanca,
• Christoph Krafft and
• Juergen Popp

Beilstein J. Nanotechnol. 2017, 8, 1183–1190, doi:10.3762/bjnano.8.120

• after testing each batch permutation were summed up. UV–vis absorption spectra of (a) silver nanoparticles with an absorption band at 415 nm and (b) solution of silver nanoparticles and potassium chloride. The absorption band of aggregated nanoparticles was shifted to near infrared region. (a) Scanning

Enhanced catalytic activity without the use of an external light source using microwave-synthesized CuO nanopetals

• Govinda Lakhotiya,
• Sonal Bajaj,
• Arpan Kumar Nayak,
• Debabrata Pradhan,
• Pradip Tekade and
• Abhimanyu Rana

Beilstein J. Nanotechnol. 2017, 8, 1167–1173, doi:10.3762/bjnano.8.118

• the same morphology, further experiments were performed with as-synthesized nanopetals. Optical study The UV–vis absorption spectra of as-synthesized CuO nanopetals is shown in the Figure 2a. It reflects a wide absorption spectrum up to 700 nm covering almost the entire visible spectrum. The

• suspension at regular intervals and were centrifuged to filter suspended CuO powder. The MB concentration in the filtered suspension was studied with a Perkin Elmer Lambda 750 UV–vis spectrophotometer. Figure 2b shows the UV–vis absorption spectra of the aliquots taken out at different time intervals. In

• out to investigate the effect of different concentrations of H2O2 for MB degradation in the absence of CuO nanopetals (catalyst) without any irradiation (UV/visible light). Figure 2c shows the UV–vis absorption spectra for different concentrations of H2O2 in MB solution, without catalyst, after one

AgCl-doped CdSe quantum dots with near-IR photoluminescence

• Pavel A. Kotin,
• Sergey S. Bubenov,
• Natalia E. Mordvinova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2017, 8, 1156–1166, doi:10.3762/bjnano.8.117

• stored in glass vials in dark. The elemental analysis was done with a Bruker Mistral M1 μ-XRF spectrometer. The Ag to Cd ratio was determined from the relative intensities of the Kα1 peaks with the use of a calibration curve (Supplementary data of [22]). UV–vis absorption measurements were carried out

ZnO nanoparticles sensitized by CuInZn_xS_2+x quantum dots as highly efficient solar light driven photocatalysts

• Florian Donat,
• Serge Corbel,
• Halima Alem,
• Steve Pontvianne,
• Lavinia Balan,
• Ghouti Medjahdi and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 1080–1093, doi:10.3762/bjnano.8.110

• nanoparticles by a thermal treatment at 400 °C for 15 min. The ZnO/ZCIS composite was characterized by TEM, SEM, XRD, XPS and UV–vis absorption spectroscopy. ZCIS QDs, with an average diameter of ≈4.5 nm, were found to be homogeneously distributed at the surface of ZnO nanoparticles. ZCIS-sensitized ZnO

• photocatalyst. Supporting Information The Supporting Information contains UV–vis absorption, photoluminescence emission and diffuse reflectance spectra, Tauc plots, EDS analysis, XPS spectra, plots of ln(C0/C), an XRD pattern and an SEM image of the reused catalyst and the photocatalytic experiments in air

• continuous stirring. Using a radiometer, the light intensity was estimated to be 5 mW/cm2. At regular intervals, 2 mL sample aliquots were withdrawn from the reaction flask and centrifuged (15,000 rpm for 2 min) to remove the photocatalyst. The photodegradation progress was monitored by measuring the UV–vis

Dispersion of single-wall carbon nanotubes with supramolecular Congo red – properties of the complexes and mechanism of the interaction

• Anna Jagusiak,
• Barbara Piekarska,
• Tomasz Pańczyk,
• Małgorzata Jemioła-Rzemińska,
• Elżbieta Bielańska,
• Barbara Stopa,
• Grzegorz Zemanek,
• Janina Rybarska,
• Irena Roterman and
• Leszek Konieczny

Beilstein J. Nanotechnol. 2017, 8, 636–648, doi:10.3762/bjnano.8.68

• total amount of CR added to the sample. UV–vis absorption spectra were recorded on a Cary 300Bio Varian spectrophotometer. Absorption coefficient for CR: ε489 = 50.46 M−1·cm−1. In order to avoid errors caused by clogging of the membrane (in case of samples containing higher amounts of CR) the filtering

Nanoscale isoindigo-carriers: self-assembly and tunable properties

• Tatiana N. Pashirova,
• Andrei V. Bogdanov,
• Lenar I. Musin,
• Julia K. Voronina,
• Irek R. Nizameev,
• Marsil K. Kadirov,
• Vladimir F. Mironov,
• Lucia Ya. Zakharova,
• Shamil K. Latypov and
• Oleg G. Sinyashin

Beilstein J. Nanotechnol. 2017, 8, 313–324, doi:10.3762/bjnano.8.34

• available classical anionic (SDS), cationic (CTAB) and nonionic (Tween 80) surfactants. Because isatin and isoindigo derivatives are new dyes, their extinction coefficients were determined for the first time. UV–vis absorption spectra of 2a–h and 3 in chloroform are presented in Figures S11–S18 (Supporting

Photocatalysis applications of some hybrid polymeric composites incorporating TiO₂ nanoparticles and their combinations with SiO₂/Fe₂O₃

• Andreea Laura Chibac,
• Tinca Buruiana,
• Violeta Melinte and
• Emil C. Buruiana

Beilstein J. Nanotechnol. 2017, 8, 272–286, doi:10.3762/bjnano.8.30

• photodecomposition process of an aqueous solution of phenol (1.06 × 10−3 M) in the presence of hybrid materials with TiO2 nanoparticles, pure or combined with SiO2 and/or Fe2O3, was investigated by monitoring the characteristic absorption band of phenol at λ = 270 nm. Figure 6a,b shows the UV–vis absorption spectra

• performed. As expected, S1 exhibited a very low photodegradation activity (Figure 7a), only 10% of phenol being reduced after 250 min of visible-light irradiation. The UV–vis absorption spectra measured in the presence of S4 hybrid (Figure 7b) show that phenol is decomposed with increasing irradiation time

• observed for aqueous hydroquinone solutions (0.5 × 10−3 M) in the presence of our hybrids catalysts S1–S4. Figure 8a displays the hydroquinone UV–vis absorption spectra under UV irradiation in the presence of S4 film. It can be observed that after only 5 min of UV irradiation the typical absorption band of

Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles

• Anurag Roy,
• Partha Pratim Das,
• Mukta Tathavadekar,
• Sumita Das and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23

• longitudinal optical (LO) phonon modes of CdS, respectively. The peak 876 cm−1 is assigned to a combination of (1LO + 2LO) [37][38]. The UV–vis absorption spectrum of CdS NPs exhibited an absorption edge (λe) at ≈480 nm (Figure 2c) which further depicted an average nanoparticle size of 4.71 nm as derived from

• NPs. (c) UV–vis absorption spectrum (Inset: corresponding Tauc Plot for optical band gap measurement) and (d) excitation wavelength dependent emission spectra of the CdS NP dispersion at room temperature. (a) Respective X-ray diffraction patterns of the CdS-sensitized ZnO-P and ZnO-R films. (b

A novel electrochemical nanobiosensor for the ultrasensitive and specific detection of femtomolar-level gastric cancer biomarker miRNA-106a

• Maryam Daneshpour,
• Kobra Omidfar and
• Hossein Ghanbarian

Beilstein J. Nanotechnol. 2016, 7, 2023–2036, doi:10.3762/bjnano.7.193

• the assembly of gold NPs and reached 20 nm. The estimated sizes from TEM images showed a good agreement with the DLS measurements (the insets). The UV–vis absorption spectrum of a colloidal solution of gold NPs is presented in Figure 2B and compared with the ones resulted from other synthesized NPs

• . The results indicated a remarkable peak near 520 nm in the gold (curve a) and final gold–magnetic (curve d) NPs analysis. This peak, which forms because of the excitation of surface plasmon vibrations and corroborates the presence of spherical gold NPs, is predictably absent in UV–vis absorption

Effect of Anderson localization on light emission from gold nanoparticle aggregates

• Mohamed H. Abdellatif,
• Marco Salerno,
• Gaser N. Abdelrasoul,
• Ioannis Liakos,
• Alice Scarpellini,
• Sergio Marras and
• Alberto Diaspro

Beilstein J. Nanotechnol. 2016, 7, 2013–2022, doi:10.3762/bjnano.7.192

• on the dielectric constant of the particles. We studied the UV–vis absorption of the AuNPs in water solution as a reference sample, assuming no aggregation in the colloidal solution. When another two samples were drop cast on the glass and on the quartz substrates, the difference in medium dielectric

• the aggregated density and pattern as explained by the theory. Figure 4a–c shows the UV–vis absorption spectra of AuNPs in solution, deposited on quartz and deposited on glass substrate, respectively. The absorption band of AuNPs on quartz is quite broad, with a FWHM of ≈150 nm, while for the AuNPs on

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

• Suneel Kumar,
• Rahul Sharma,
• Vipul Sharma,
• Gurunarayanan Harith,
• Vaidyanathan Sivakumar and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2016, 7, 1684–1697, doi:10.3762/bjnano.7.161

• spectra of (a) GO, (b) ZnO, (c) CdS, (d) CdS–ZnO and (e) CdS–ZnO–RGO nanocomposite. UV–vis absorption spectra of GO, ZnO NR, CdS NP, CdS–ZnO and CdS–ZnO–RGO nanocomposite. Time-dependent UV–vis spectra of photocatalytic degradation of MO: (a) visible light irradiation from a solar simulator using CdS–ZnO