In situ optical sub-wavelength thickness control of porous anodic aluminum oxide

• Aleksandrs Dutovs,
• Raimonds Popļausks,
• Oskars Putāns,
• Vladislavs Perkanuks,
• Aušrinė Jurkevičiūtė,
• Tomas Tamulevičius,
• Uldis Malinovskis,
• Iryna Olyshevets,
• Donats Erts and
• Juris Prikulis

Beilstein J. Nanotechnol. 2024, 15, 126–133, doi:10.3762/bjnano.15.12

• , Latvia Faculty of Physics, Mathematics and Optometry, University of Latvia, 3 Jelgavas Str., Riga LV-1004, Latvia 10.3762/bjnano.15.12 Abstract Porous anodic aluminum oxide (PAAO), sometimes referred to as nanoporous anodic alumina, serves as a cost-effective template for nanofabrication in many fields

• microscopy and is particularly valuable for the small-scale production of PAAO-based functional optical coatings. Keywords: electrochemistry; ellipsometry; porous anodic alumina; spectroscopy; thin films; Introduction Porous anodic aluminum oxide (PAAO) is a versatile self-organized material with

• stage of anodization, the alumina layer may not be correctly represented by a single-layer effective RI. This typically resulted in fitting errors during the first 1–2 min of anodization (hPAAO < 200 nm) as shown in Figure 3a. Moreover, the LM algorithm is sensitive to the initial guess value of the fit

A graphene quantum dots–glassy carbon electrode-based electrochemical sensor for monitoring malathion

• Sanju Tanwar,
• Aditi Sharma and
• Dhirendra Mathur

Beilstein J. Nanotechnol. 2023, 14, 701–710, doi:10.3762/bjnano.14.56

• collected after centrifugation. To obtain the GQDs, the final black suspension was filtered through a 0.22 µm syringe filter. Fabrication of the electrochemical sensor A mirror-like surface was first achieved on the bare GCE by polishing it with 0.3 and 0.05 μm alumina powder. In the next step the GCE was

On the use of Raman spectroscopy to characterize mass-produced graphene nanoplatelets

• Keith R. Paton,
• Konstantinos Despotelis,
• Naresh Kumar,
• Piers Turner and
• Andrew J. Pollard

Beilstein J. Nanotechnol. 2023, 14, 509–521, doi:10.3762/bjnano.14.42

• was then vacuum-filtered through alumina membranes (20 nm pore size), rinsed with IPA to remove residual NMP, and dried in a vacuum oven at 60 °C overnight. For samples 2 to 7, 3 mL of the dispersion was filtered, while for sample 1, ca. 30 mL was used to ensure adequate coverage of the membrane

Mixed oxides with corundum-type structure obtained from recycling can seals as paint pigments: color stability

• Dienifer F. L. Horsth,
• Julia de O. Primo,
• Nayara Balaba,
• Fauze J. Anaissi and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2023, 14, 467–477, doi:10.3762/bjnano.14.37

• sample (alumina) (Figure 1a) shows single-phase θ-Al2O3, which is an alumina phase obtained through heat treatment above 900 °C [16]. In the diffractogram of sample 1 (Figure 1b), two phases are observed, θ-Al2O3 [96-120-0006] and eskolaite α-Cr2O3 [96-901-6564]. The crystal structure of the eskolaite

• from 57.3% (alumina) to 63.9% (sample 2) (Table 1). The crystallinity of the synthesized oxides is superior to the ones obtained via coprecipitation [1]. Raman spectroscopy The Raman spectrum observed for sample 1 (Figure 2a) is characteristic of chromium oxide (Cr2O3), in agreement with what was

• Regarding the colorimetric parameters (Table 3), it was observed that the pristine alumina sample is the most luminous (79.75) with the lowest chromaticity (C*). The addition of coloring ions yielded a very strong color difference in the samples in relation to the alumina sample, varying the chromatic

Hydroxyapatite–bioglass nanocomposites: Structural, mechanical, and biological aspects

• Olga Shikimaka,
• Mihaela Bivol,
• Bogdan A. Sava,
• Marius Dumitru,
• Christu Tardei,
• Beatrice G. Sbarcea,
• Daria Grabco,
• Constantin Pyrtsac,
• Daria Topal,
• Andrian Prisacaru,
• Vitalie Cobzac and
• Viorel Nacu

Beilstein J. Nanotechnol. 2022, 13, 1490–1504, doi:10.3762/bjnano.13.123

• was heated up to 240 °C in an electrical oven, than introduced in an alumina crucible and heated in an electric furnace in two steps, namely a pre-melting step at low heating rate of about 50 °C/h from 240 up to 800 °C, followed by a melting step, at a higher heating rate of 250 °C/h, up to the

• melting temperature of 1200 °C, where the mixture maintained for 0.5 h. To obtain a homogeneous glass, an alumina stirrer homogenized the melt at 200–240 rpm. (iv) Casting, that is, the melt was cast into graphite molds, previously preheated at 1.1 Tg. (v) Cooling of the glass in air. (vi) Grinding the

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

• Nirmalendu S. Mishra and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2022, 13, 1380–1392, doi:10.3762/bjnano.13.114

• was fixed at 80 wt %. The obtained mixture was placed in a boat-type alumina crucible and subjected to heat treatment in a tube furnace at 900 °C for 3 h with a heating ramp rate of 5 °C/min under nitrogen atmosphere. Finally, the obtained MBN was naturally cooled to room temperature, washed multiple

Studies of probe tip materials by atomic force microscopy: a review

• Ke Xu and
• Yuzhe Liu

Beilstein J. Nanotechnol. 2022, 13, 1256–1267, doi:10.3762/bjnano.13.104

• criteria required for a high-quality AFM conductive probe. Colloidal probe Colloidal probes (CPs) [47] can simulate the determination of forces between many types of colloidal particles, such as silica-alumina cellulose, and have several advantages for accurate force measurements: tunable and well

• the sample, and are suitable for high-resolution test experiments. Colloidal probes are mainly used to study colloidal interactions. They can simulate the determination of the forces between various types of colloidal particles such as silica-alumina cellulose, providing a good detection tool for a

A nonenzymatic reduced graphene oxide-based nanosensor for parathion

• Sarani Sen,
• Anurag Roy,
• Ambarish Sanyal and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2022, 13, 730–744, doi:10.3762/bjnano.13.65

• micron alumina slurry (CHI Instruments) on micro cloth pads sequentially to a mirror-like finish with fine wet emery paper (grain size 4000), and rinsed with ultrapure water. Then the electrode was separately dipped into concentrated NaOH, nitric acid, and methanol for 120 s, followed by sonication in

Tubular glassy carbon microneedles with fullerene-like tips for biomedical applications

• Sharali Malik and
• George E. Kostakis

Beilstein J. Nanotechnol. 2022, 13, 455–461, doi:10.3762/bjnano.13.38

• the nanoarchitectonics concept of bottom-up creation of functional materials, we use methane rather than a polymer to form glassy carbon. Here we show that tubular glassy carbon microneedles with fullerene-like tips form when methane undergoes pyrolysis on a curved alumina surface. X-ray diffraction

• al. observed that carbon deposition in the mesopores of alumina is responsible for catalytic activity resulting in the decomposition of methane [12]. Here, we examine the characteristics of the glassy carbon produced by catalytic pyrolysis of methane. Our results show clear experimental evidence for

• pyrolysis of methane on a curved alumina surface. The surface provides the catalyst as well as the “strain” required to direct nucleation and growth. Figure 1a is a scanning electron microscopy (SEM) overview image showing a number of glassy carbon microneedles, which grow in the direction of the gas flow

Selected properties of Al_xZn_yO thin films prepared by reactive pulsed magnetron sputtering using a two-element Zn/Al target

• Witold Posadowski,
• Artur Wiatrowski,
• Jarosław Domaradzki and
• Michał Mazur

Beilstein J. Nanotechnol. 2022, 13, 344–354, doi:10.3762/bjnano.13.29

• of aluminum oxide in such targets is approximately 2% [6][7][8][9][10][11][12][13][14][15][16][17][18]. However, in research in which the objective was to obtain films with minimum resistivity, the alumina content was typically varied in the range of 1–6% [8][9][12]. AZO films have also been obtained

Photothermal ablation of murine melanomas by Fe₃O₄ nanoparticle clusters

• Xue Wang,
• Lili Xuan and
• Ying Pan

Beilstein J. Nanotechnol. 2022, 13, 255–264, doi:10.3762/bjnano.13.20

• effects of alumina-coated Fe3O4 nanoparticles against bacteria upon exposure to NIR light [13]. Further studies with esophageal cancer demonstrate that Fe3O4 nanoparticles induce hyperthermia post absorption to suppress tumor growth in a dosage-dependent manner [14]. However, due to very high dosage

Plasmon-enhanced photoluminescence from TiO₂ and TeO₂ thin films doped by Eu³⁺ for optoelectronic applications

• Marcin Łapiński,
• Jakub Czubek,
• Katarzyna Drozdowska,
• Anna Synak,
• Wojciech Sadowski and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2021, 12, 1271–1278, doi:10.3762/bjnano.12.94

• basis of emission spectra for structures with alumina oxide, 4 nm of titanium dioxide was selected as a dielectric layer. The optical characteristics are presented in Figure 12 and Figure 13. Because of the different dielectric constants of both types of dielectric layers, a shift of plasmon resonance

Uniform arrays of gold nanoelectrodes with tuneable recess depth

• Elena O. Gordeeva,
• Ilya V. Roslyakov,
• Alexey P. Leontiev,
• Alexey A. Klimenko and
• Kirill S. Napolskii

Beilstein J. Nanotechnol. 2021, 12, 957–964, doi:10.3762/bjnano.12.72

• approaches for the preparation of such systems is templated electrodeposition. In the present study, porous anodic alumina templates are used to prepare Au nanoelectrode arrays. Multistage electrodeposition is proposed for the formation of recessed electrodes with the ability to tune the distance between the

• pathways to further improve the recessed nanoelectrode arrays based on anodic alumina templates are discussed. Keywords: anodic alumina; gold; nanoelectrode array; recessed electrode; templated electrodeposition; Introduction A nanoelectrode array (NEA) is a set of regularly arranged isolated metal

• of Cu/Au/Cu segments into the pores of an anodic alumina template with the subsequent selective dissolution of the sputtered Cu current collector and the first Cu segment. The reported design of NEAs allows one to tune the recess of Au nanoelectrodes relative to the AAO surface with high precision

The role of deep eutectic solvents and carrageenan in synthesizing biocompatible anisotropic metal nanoparticles

• Nabojit Das,
• Akash Kumar and
• Raja Gopal Rayavarapu

Beilstein J. Nanotechnol. 2021, 12, 924–938, doi:10.3762/bjnano.12.69

• maintaining high yield and monodispersity. Initially, gold nanorods were synthesized using electrochemical methods using polycarbonate membrane templates or porous alumina for shape control in the presence of surfactants (mostly CTAB) [34][35]. Because of their optical properties, gold nanorods became

Solution combustion synthesis of a nanometer-scale Co₃O₄ anode material for Li-ion batteries

• Monika Michalska,
• Huajun Xu,
• Qingmin Shan,
• Shiqiang Zhang,
• Yohan Dall'Agnese,
• Yu Gao,
• Amrita Jain and
• Marcin Krajewski

Beilstein J. Nanotechnol. 2021, 12, 424–431, doi:10.3762/bjnano.12.34

• , the resulting gel precursor was heated in an alumina crucible from 300 to 700 °C for 5 h in air. The flowchart of the synthesis is presented in Figure 4. Characterization of the Co3O4 material: The structural properties of the Co3O4 material were determined using powder X-ray diffraction (XRD) and

Mapping the local dielectric constant of a biological nanostructured system

• Wescley Walison Valeriano,
• Rodrigo Ribeiro Andrade,
• Juan Pablo Vasco,
• Angelo Malachias,
• Bernardo Ruegger Almeida Neves,
• Paulo Sergio Soares Guimarães and
• Wagner Nunes Rodrigues

Beilstein J. Nanotechnol. 2021, 12, 139–150, doi:10.3762/bjnano.12.11

• surface is stronger than on the alumina disk. The tip radius was obtained using the α coefficient for measurements on the gold surface for h = 0, and was R = (36.7 ± 0.2) nm (Figure 9b). The tip–sample distance z is 44 nm, determined by the sum of 40 nm of the lift height of the setup and the 4 nm of the

• alumina film disk on gold. Acknowledgements The authors would like to thank Prof. Angelo Machado (in memoriam) for his generosity and enthusiasm for this work, supplying us with the precious specimens of damselflies studied here. We acknowledge the Center of Microscopy at the Universidade Federal de

Atomic layer deposited films of Al₂O₃ on fluorine-doped tin oxide electrodes: stability and barrier properties

• Hana Krýsová,
• Michael Neumann-Spallart,
• Hana Tarábková,
• Pavel Janda,
• Ladislav Kavan and
• Josef Krýsa

Beilstein J. Nanotechnol. 2021, 12, 24–34, doi:10.3762/bjnano.12.2

• amorphous to polycrystalline γ-Al2O3 [12] or to oriented θ-Al2O3 [13]. However, on thermodynamic grounds, alumina is soluble in both acidic and alkaline media [8]. Besides protection, Al2O3 ALD layers have also been used for passivating surface states on water-oxidizing hematite photoanodes [14][15]. Very

• alumina coatings was ascribed to its capability of passivating semiconductor/electrolyte interfaces, thus reducing photogenerated charge-carrier recombination (e.g., on BiVO4 [16]). In this work, Al2O3 films were deposited via ALD on thermally grown SiO2 on silicon or on fluorine-doped tin oxide (FTO

• buffer, pH 7.2) are shown in Figure S6 (Supporting Information File 1). The change in the surface nanoscale morphology can be explained by the replacement of SnO2 by Sn. Figure 8 and Table 2 show that increasing thickness values of ALD alumina layers led to an increase in the efficacy of suppression of

Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

• Matías Guerrero Correa,
• Fernanda B. Martínez,
• Cristian Patiño Vidal,
• Camilo Streitt,
• Juan Escrig and
• Carol Lopez de Dicastillo

Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129

• particle sizes, are listed in Table 2. The atomic layer deposition method is employed to grow metal oxide and metallic three-dimensional nanostructures using porous alumina membranes [41], electrostatically spun nanofibers [39][40] or electrosprayed spherical particles [38] as templates. As Figure 1 shows

Plant growth regulation by seed coating with films of alginate and auxin-intercalated layered double hydroxides

• Vander A. de Castro,
• Valber G. O. Duarte,
• Danúbia A. C. Nobre,
• Geraldo H. Silva,
• Vera R. L. Constantino,
• Frederico G. Pinto,
• Willian R. Macedo and
• Jairo Tronto

Beilstein J. Nanotechnol. 2020, 11, 1082–1091, doi:10.3762/bjnano.11.93

• analyses (TG-DSC-MS) were performed on a Netzsch thermoanalyzer model TGA/DSC 409 PC – Luxx coupled to an Aëolos 403 C mass spectrometer, using alumina crucibles and a heating rate of 10 °C/min under synthetic air flow of 50 cm3/min from ambient temperature up to 1000 °C. Surface area analysis was

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

Beilstein J. Nanotechnol. 2020, 11, 1010–1018, doi:10.3762/bjnano.11.85

• present work is related to investigations of the interaction between nanostructured Te films and toxic gases. According to the literature, such investigations firstly have been provided utilizing the nanocrystalline Te films grown onto Pyrex glass, alumina (Al2O3), oxidized silicon or sapphire substrates

A 3D-polyphenylalanine network inside porous alumina: Synthesis and characterization of an inorganic–organic composite membrane

• Jonathan Stott and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2020, 11, 938–951, doi:10.3762/bjnano.11.78

• ) in porous alumina membranes (ALOX-membranes) with respect to different solvent mixtures (tetrahydrofuran (THF) and dichloromethane (DCM)). It was found that increasing the volume fraction of DCM leads to an increasing amount of fibrillar polymer structures within the porous ALOX-membrane. A three

• polymer functionalization schemes for reversed-phase solid phase extraction applications. The adsorption capability of the functionalized composite membrane was increased from 16.7% to 38.1% compared to the native ALOX-membrane. Keywords: alumina; composite membrane; polymer-based sorbent

• ; polyphenylalanine; porous alumina membranes; surface-initiated ring-opening polymerization (SI-ROP); Introduction Porous materials with functional surfaces are a topic of immense interest in science and technology. The high surface area and high mechanical stability of such materials allows for applications in

Transition from freestanding SnO₂ nanowires to laterally aligned nanowires with a simulation-based experimental design

• Jasmin-Clara Bürger,
• Sebastian Gutsch and
• Margit Zacharias

Beilstein J. Nanotechnol. 2020, 11, 843–853, doi:10.3762/bjnano.11.69

• downstream temperature zone. An alumina boat with 0.3 g of a 1:1 w/w% mixture of pulverized SnO2:graphite was placed in the upstream temperature zone. After closing the system, the pressure was pumped down to a vacuum level below 4.6 × 10−5 mbar by means of a turbo molecular pump. This step was performed to

Exfoliation in a low boiling point solvent and electrochemical applications of MoO₃

• Matangi Sricharan,
• Bikesh Gupta,
• Sreejesh Moolayadukkam and
• H. S. S. Ramakrishna Matte

Beilstein J. Nanotechnol. 2020, 11, 662–670, doi:10.3762/bjnano.11.52

• (SCE) as reference electrode were used for the electrochemical testing of the exfoliated MoO3 dispersions and its composites. In brief, the GCE was cleaned with a polishing cloth using fine alumina abrasive powders and washed thoroughly in deionized water. The required amount of the dispersion of known

Abrupt elastic-to-plastic transition in pentagonal nanowires under bending

• Sergei Vlassov,
• Magnus Mets,
• Boris Polyakov,
• Jianjun Bian,
• Leonid Dorogin and
• Vahur Zadin

Beilstein J. Nanotechnol. 2019, 10, 2468–2476, doi:10.3762/bjnano.10.237

• -fold twinned structure prevents propagation of critical defects, leading to dislocation pile up that may lead to sudden stress release, which is observed as an abrupt plastic event. Moreover, we found that if the NWs are coated with alumina, the abrupt plastic event is not observed and the NWs can

• demonstrate an unusual, abrupt elastic-to-plastic transition, observed as a sudden change of the NW profile from smooth arc-shaped to angled knee-like during the bending in the narrow range of bending angles (critical bending angle). Moreover, we show that if the NWs are coated with alumina, an abrupt plastic

• extreme surface-to-volume ratio. If surface nucleation is mitigated by, for example, external materials (coating), the onset of plastic yield can be significantly postponed. Hence, we performed a few preliminary tests on Ag NWs coated by atomic layer deposition (ALD) with a few-nm thick layer of alumina

pH-Controlled fluorescence switching in water-dispersed polymer brushes grafted to modified boron nitride nanotubes for cellular imaging

• Saban Kalay,
• Yurij Stetsyshyn,
• Volodymyr Donchak,
• Khrystyna Harhay,
• Ostap Lishchynskyi,
• Halyna Ohar,
• Yuriy Panchenko,
• Stanislav Voronov and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2019, 10, 2428–2439, doi:10.3762/bjnano.10.233

• ) and Fe2O3 (0.166 g) [25]. Briefly, the precursor mixture was transferred to an alumina boat and preheated at 180 °C for 15 min and then the alumina boat was placed into the center of the tubular furnace (Protherm, Furnaces PTF 14/50/450). The BNNT synthesis was performed under saturated NH3 atmosphere

• . The furnace temperature was set to a heating rate of 8 °C/min up to 1280 °C and then held at this temperature for 3 h. The furnace was cooled down to ambient temperature. Thereafter, the BNNTs were collected from the top of the alumina boat and stored in a dry environment. For the purification, the