A silver-nanoparticle/cellulose-nanofiber composite as a highly effective substrate for surface-enhanced Raman spectroscopy

• Yongxin Lu,
• Yan Luo,
• Zehao Lin and
• Jianguo Huang

Beilstein J. Nanotechnol. 2019, 10, 1270–1279, doi:10.3762/bjnano.10.126

• bacterial nanocellulose adsorbed with gold nanoparticles in the form of a hydrogel had a detection limit of 1 × 10−9 M for R6G [54], the Au–Ag bimetallic microfluidic SERS sensor had a detection limit of 1 × 10−13 M for the same analyte [64]; and a detection limit of 1 × 10−6 M was offered by a hybrid

Angle-dependent structural colors in a nanoscale-grating photonic crystal fabricated by reverse nanoimprint technology

• Xu Zheng,
• Qing Wang,
• Jinjin Luan,
• Yao Li,
• Ning Wang and
• Rui Zhang

Beilstein J. Nanotechnol. 2019, 10, 1211–1216, doi:10.3762/bjnano.10.120

• , there is a blue-shift of the peak wavelength when the observation angle is increased. An equation for the observed wavelength as a function of the observation angle is proposed. Keywords: observation angle; photonic crystal; reverse nanoimprint lithography; structural color; visualized sensor

• ][17][18][19]. Duempelmann et al. fabricated asymmetric periodic nanostructures to explore the effects of the optical properties on the structural color [20]. Then, they used the photonic crystal as a strain sensor by mechanically changing the structural period to achieve the different structural

• experimental results, a function for reflection wavelength and observation angle is proposed. These results are useful for a possible application as visual sensor. Results and Discussion Figure 1 shows scanning electron microscopy (SEM) images of the photonic crystal with nanoscale grating pattern. The top

Direct growth of few-layer graphene on AlN-based resonators for high-sensitivity gravimetric biosensors

• Jimena Olivares,
• Teona Mirea,
• Lorena Gordillo-Dagallier,
• Bruno Marco,
• José Miguel Escolano,
• Marta Clement and
• Enrique Iborra

Beilstein J. Nanotechnol. 2019, 10, 975–984, doi:10.3762/bjnano.10.98

• quartz crystal microbalances (QCMs), and can be configured in sensor arrays and integrated (on-wafer or in-package) along with their driving electronics and microfluidic arrangements, offering compact and inexpensive measurement systems [5][6]. Among the wide variety of thin-film resonators exploiting

• sensor with the desired selectivity and sensitivity to the targeted species. Selectivity mainly depends on the specificity of the receptor (e.g., for proteins, aptamers or antibodies) to the targeted species and the non-specific binding degree of other species that can be achieved; effective

• also account for the observed trend. The response of the SMR-based gravimetric sensor is comparable to that obtained in similar biosensors subjected to a silane-based functionalization [24]. Non-covalent functionalization According to previous studies [25], non-covalent binding is possible on pristine

Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures

• Jad Sabek,
• Francisco Javier Díaz-Fernández,
• Luis Torrijos-Morán,
• Zeneida Díaz-Betancor,
• Ángel Maquieira,
• María-José Bañuls,
• Elena Pinilla-Cienfuegos and
• Jaime García-Rupérez

Beilstein J. Nanotechnol. 2019, 10, 967–974, doi:10.3762/bjnano.10.97

• sites towards the target sample. Then, the biofunctionalized PBG biosensor has been used to perform a direct and real-time detection of the target BSA antigen. Keywords: evanescent field; half-antibodies; light-assisted immobilization; photonic bandgap sensor; SNOM characterization; Introduction The

• that part of the optical mode going into the cladding, it is important to maximize that interaction. This is achieved for distances closer to the sensor surface, where the intensity of the evanescent field is higher. Therefore, to achieve an optimum biodetection performance, it is important to consider

• optical microscopy (SNOM) in order to determine how the interaction will vary with the distance to the sensor surface. This near-field characterization has demonstrated the importance of having biorecognition layers being as thin as possible in order to reach optimal sensitivities. Taking this requirement

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

• Alberto Perrotta,
• Julian Pilz,
• Stefan Pachmajer,
• Antonella Milella and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2019, 10, 746–759, doi:10.3762/bjnano.10.74

• layers, the THMS600 temperature stage was equipped with a custom-made humidity pump, and the principles of ellipsometric porosimetry (EP) were used. The relative humidity was monitored via a sensor in the measurement chamber (Sparkfun SHT-15) and tuned in the range of 0–95% [44]. In this way, pores with

Commercial polycarbonate track-etched membranes as substrates for low-cost optical sensors

• Paula Martínez-Pérez and
• Jaime García-Rupérez

Beilstein J. Nanotechnol. 2019, 10, 677–683, doi:10.3762/bjnano.10.67

• porous sensors with such easily available mesoporous material. Keywords: chemical sensor; Fabry–Pérot interferometer; optical sensor; polycarbonate; track-etched membrane; Introduction Sensors are present in our daily life in order to detect and monitor chemical, biological and physical agents of

• an evanescent field with the target substance are the best known [2]. However, this kind of optical sensor presents a limited sensitivity, as only part of the light interacts with the substances of interest. To overcome this limitation, porous materials are a good option. Since they allow the

• shift registered for the first FTIR measurement after the deposition of the drop is the maximum shift achieved by the spectrum, as the liquid could have slightly evaporated during this time lapse [16] allowing the air to refill the pores. To check this, we calculated the sensitivity of our sensor

A carrier velocity model for electrical detection of gas molecules

• Ali Hosseingholi Pourasl,
• Sharifah Hafizah Syed Ariffin,
• Mohammad Taghi Ahmadi,
• Razali Ismail and
• Niayesh Gharaei

Beilstein J. Nanotechnol. 2019, 10, 644–653, doi:10.3762/bjnano.10.64

• remarkable changes in their electrical characteristics when exposed to different gases through molecular adsorption. In this paper, the adsorption effects of the target gas molecules (CO and NO) on the electrical properties of the armchair graphene nanoribbon (AGNR)-based sensor are analytically modelled

• the presence of the gas molecules. Furthermore, the I–V characteristics and energy band structure of the AGNR sensor are simulated using first principle calculations to investigate the gas adsorption effects on these properties. To ensure the accuracy of the proposed model, the I–V characteristics of

• the AGNR sensor that are simulated based both on the proposed model and first principles calculations are compared, and an acceptable agreement is achieved. Keywords: armchair graphene nanoribbons; carrier velocity; gas sensor; I–V characteristics; molecular adsorption; Introduction The unique

Hydrophilicity and carbon chain length effects on the gas sensing properties of chemoresistive, self-assembled monolayer carbon nanotube sensors

• Juan Casanova-Cháfer,
• Carla Bittencourt and
• Eduard Llobet

Beilstein J. Nanotechnol. 2019, 10, 565–577, doi:10.3762/bjnano.10.58

• attributed to the interaction, via strong hydrogen bonding, of the polar molecules tested to the polar surface of hydrophilic thiols. The approach discussed here could be extended further by combining hydrophilic and hydrophobic thiol SAMs in Au-MWCNT sensor arrays as a helpful strategy for tuning sensor

• gas sensitive nanomaterial to higher temperatures [3] or to irradiate the sensor employing ultraviolet (UV) light, in order to promote surface cleaning. Despite these efforts, sometimes CNTs present irreversible resistance changes due to the chemisorption of gas molecules. In addition, other problems

• such as lack of selectivity, environmental variations (e.g., changes in humidity level) affecting sensor response, or the difficulty to detect gases characterized by low adsorption energies are often encountered [11]. In order to enhance their selectivity and/or their sensitivity, CNTs have been

Wearable, stable, highly sensitive hydrogel–graphene strain sensors

• Jian Lv,
• Chuncai Kong,
• Chao Yang,
• Lu Yin,
• Itthipon Jeerapan,
• Fangzhao Pu,
• Xiaojing Zhang,
• Sen Yang and
• Zhimao Yang

Beilstein J. Nanotechnol. 2019, 10, 475–480, doi:10.3762/bjnano.10.47

• 21500, P. R. China Research institute of Xi'an Jiaotong University, Hangzhou, Zhejiang, 311215, P. R. China 10.3762/bjnano.10.47 Abstract A stable and highly sensitive graphene/hydrogel strain sensor is designed by introducing glycerol as a co-solvent in the formation of a hydrogel substrate and then

• casting a graphene solution onto the hydrogel in a simple, two-step method. This hydrogel-based strain sensor can effectively retain water in the polymer network due to the formation of strong hydrogen bonding between glycerol and water. The addition of glycerol not only enhances the stability of the

• sensor to be used in both stretching and bending modes. As a demonstration, the as-prepared strain sensor was applied to sense the movement of finger knuckles. Given the outstanding performance of this wearable sensor, together with the proposed scalable fabrication method, this stable and sensitive

Temperature-dependent Raman spectroscopy and sensor applications of PtSe₂ nanosheets synthesized by wet chemistry

• Mahendra S. Pawar and
• Dattatray J. Late

Beilstein J. Nanotechnol. 2019, 10, 467–474, doi:10.3762/bjnano.10.46

• well with the reported 2D transition metal dichalcogenides. A PtSe2 nanosheet-based sensor device was tested for its applicability as a humidity sensor and photodetector. The humidity sensor based on PtSe2 nanosheets showed an excellent recovery time of ≈5 s, indicating the great potential of PtSe2 for

• future sensor devices. Keywords: nanosheets; PtSe2; Raman spectroscopy; sensor; thermal effect; Introduction Graphene, the most well-studied example of the two-dimensional (2D) aromatic compounds, is the building block of all forms of carbon allotropes [1]. In recent years, it has been widely studied

• onto a Si substrate and heated at 100 °C on a hot plate. After complete evaporation, the substrate was annealed in a chemical vapour deposition system at 500 °C in argon gas atmosphere for 5 h. Supporting Information File 1, Figure S1 shows the schematic of the PtSe2 nanosheet synthesis steps. Sensor

Ultraviolet patterns of flowers revealed in polymer replica – caused by surface architecture

• Anna J. Schulte,
• Matthias Mail,
• Lisa A. Hahn and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2019, 10, 459–466, doi:10.3762/bjnano.10.45

• (Camag, Muttenz, Switzerland) illumination at 366 nm. An extension of the sensor detection spectrum of the D 300s camera from 340 nm to 1100 nm was implemented by Optik Makario (Mönchengladbach, Germany) and allowed images in the UV-spectrum to be captured. An analog Nikon FM2 was used to take pictures

Sub-wavelength waveguide properties of 1D and surface-functionalized SnO₂ nanostructures of various morphologies

• Venkataramana Bonu,
• Binaya Kumar Sahu,
• Arindam Das,
• Sankarakumar Amirthapandian,
• Sandip Dhara and
• Harish C. Barshilia

Beilstein J. Nanotechnol. 2019, 10, 379–388, doi:10.3762/bjnano.10.37

• commercial application as a gas sensor, transparent conducting electrodes, and catalyst [13][14][15]. SnO2 NSs have been used in several other areas such as sub-wavelength waveguide sensors [4], microelectronics [6], Li-ion batteries [16], and lubricants [17]. Oxygen vacancy related defects in SnO2

Transport signatures of an Andreev molecule in a quantum dot–superconductor–quantum dot setup

• Zoltán Scherübl,
• András Pályi and
• Szabolcs Csonka

Beilstein J. Nanotechnol. 2019, 10, 363–378, doi:10.3762/bjnano.10.36

• the price of decreasing the currents, too. Charge sensing [76][77] is another method to map out the boundaries of the phase diagram, as we illustrate in the right column of Figure 2. A charge sensor is usually engineered to be mostly sensitive to the average electron occupation of one of the quantum

• charge sensor is an additional device element. Similar methods, yielding information related to average electron occupation, are based on reflectometry with electromagnetic radiofrequency signals [78][79] or microwave resonators [80][81]; those are not discussed further in this work. The ground-state

• tunnel-coupled to the QD–SC–QD system. Transport Calculation As pointed out earlier, a charge-sensing measurement is demanding, since the addition of the charge sensor complicates device fabrication. However, the ground-state phase diagrams discussed above can also be explored experimentally by

Intuitive human interface to a scanning tunnelling microscope: observation of parity oscillations for a single atomic chain

• Sumit Tewari,
• Jacob Bakermans,
• Christian Wagner,
• Federica Galli and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2019, 10, 337–348, doi:10.3762/bjnano.10.33

• structural evolution of the junction during the manipulation operation and alter the trajectory at will. Figure 1 shows the scheme of communication between operator and STM using the MD simulator. The 3D motion tracking sensor sends the same x,y,z- signals to both the STM and the simulator simultaneously and

• the operator, and depends on the speed with which the 3D motion control sensor is moved. In the scale of the operator this is approximately 5 cm/sec, which corresponds to 1 Å/sec on the atomic scale. We perform a classical MD simulation here in which we ignore the electronic effects (which in fact

Nitrous oxide as an effective AFM tip functionalization: a comparative study

• Taras Chutora,
• Bruno de la Torre,
• Pingo Mutombo,
• Jack Hellerstedt,
• Jaromír Kopeček,
• Pavel Jelínek and
• Martin Švec

Beilstein J. Nanotechnol. 2019, 10, 315–321, doi:10.3762/bjnano.10.30

• with exposures of 0.5–1.7 L. AFM measurements were performed with a qPlus sensor (resonance frequency ca. 30 kHz; k ≈ 1800 N/m), using an oscillation amplitude of 50 pm. Prior to functionalization, the Pt tip was repeatedly indented into the Au(111) substrate several nanometers deep for sharpening and

Relation between thickness, crystallite size and magnetoresistance of nanostructured La_1−xSr_xMn_yO_3±δ films for magnetic field sensors

• Rasuole Lukose,
• Valentina Plausinaitiene,
• Milita Vagner,
• Nerija Zurauskiene,
• Skirmantas Kersulis,
• Virgaudas Kubilius,
• Karolis Motiejuitis,
• Birute Knasiene,
• Voitech Stankevic,
• Zita Saltyte,
• Martynas Skapas,
• Algirdas Selskis and
• Evaldas Naujalis

Beilstein J. Nanotechnol. 2019, 10, 256–261, doi:10.3762/bjnano.10.24

• films consisting of columnar nanograins have already been successfully applied for the sensing of high pulsed magnetic fields (B-scalar sensor) [13][14]. Despite this development, the scalar (independent of field orientation) CMR effect under a low magnetic field is still a challenging goal towards

Magnetic-field sensor with self-reference characteristic based on a magnetic fluid and independent plasmonic dual resonances

• Kun Ren,
• Xiaobin Ren,
• Yumeng He and
• Qun Han

Beilstein J. Nanotechnol. 2019, 10, 247–255, doi:10.3762/bjnano.10.23

• , Tianjin 300222, China 10.3762/bjnano.10.23 Abstract A magnetic-field sensor with self-reference characteristic based on metal–dielectric–metal (MDM) plasmonic waveguides and a magnetic fluid (MF) is proposed and theoretically investigated. Independent dual resonances are supported by the coupled

• resonances on the external field, a magnetic-field sensor with self-reference characteristic is achieved. The magnetic-field nanosensor shows an excellent performance with a high sensitivity of 27 pm/Oe, i.e., 270 pm/mT. The proposed sensor takes advantage of the refractive-index tunability of the MF and the

• compactness of the MDM waveguide structure. This research may open new opportunities to design nanoscale magnetic sensors with good performance. Keywords: dual resonance; magnetic fluid; magnetic sensor; plasmonic waveguide; self-reference; surface plasmon polaritons; Introduction Sensors that can detect

Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing

• Hussam M. Elnabawy,
• Juan Casanova-Chafer,
• Badawi Anis,
• Mostafa Fedawy,
• Mattia Scardamaglia,
• Carla Bittencourt,
• Ahmed S. G. Khalil,
• Eduard Llobet and
• Xavier Vilanova

Beilstein J. Nanotechnol. 2019, 10, 105–118, doi:10.3762/bjnano.10.10

• with iron oxide nanoparticles substantially ameliorated the response towards nitrogen dioxide. Keywords: benzene detection; doping; gas sensor; metal nanoparticle decoration; multiwalled carbon nanotubes; NO2 detection; room temperature gas sensing; surface modification; Introduction Carbon nanotubes

• ) well below air quality guidelines [24][25], which indicates the importance of fabricating such a gas sensor to be used in different applications. In this paper, we report on a wet chemistry route that was successfully employed to chemically modify CNTs by decorating them with iron oxide nanoparticles

• study of the gas sensing properties of the different hybrid nanomaterials was conducted in an effort to determine the optimal functionalization parameters to maximize sensor response. The selectivity of the resulting layer for potential interfering gases such as CO and benzene has also been investigated

Graphene–graphite hybrid epoxy composites with controllable workability for thermal management

• Idan Levy,
• Eyal Merary Wormser,
• Maxim Varenik,
• Matat Buzaglo,
• Roey Nadiv and
• Oren Regev

Beilstein J. Nanotechnol. 2019, 10, 95–104, doi:10.3762/bjnano.10.9

• method requires a transiently heated plane sensor, which consists of an electrically conducting pattern in the shape of a double spiral. This spiral is sandwiched between two thin sheets of an insulating material (kapton). When performing a TD measurement, the plane Hot Disk sensor is fitted within the

• two composite samples. While heating up, the sensor measures the temperature increase inside the sample over time. The time-dependent change in temperature is used to calculate the TD and thermal conductivity of the measured material. The measurements were conducted in air at 25 °C [67]. Electron

Pull-off and friction forces of micropatterned elastomers on soft substrates: the effects of pattern length scale and stiffness

• Peter van Assenbergh,
• Marike Fokker,
• Julian Langowski,
• Jan van Esch,
• Marleen Kamperman and
• Dimitra Dodou

Beilstein J. Nanotechnol. 2019, 10, 79–94, doi:10.3762/bjnano.10.8

• samples without a terminal layer. For these two conditions, one of the five measurements could not be completed because the sensor reached its maximum capacity. Because of the small sample size, we refrained from presenting boxplots with median and interquartile range, and present only raw data instead

• friction stress on glass for samples of PDMS-580 with various geometries and feature sizes. Sub-microscale samples without terminal layer seem to generate higher friction than the remainder of the samples, but we refrain from drawing any conclusions, as for 6 out of the 35 measurements the sensor reached

Bidirectional biomimetic flow sensing with antiparallel and curved artificial hair sensors

• Claudio Abels,
• Antonio Qualtieri,
• Toni Lober,
• Alessandro Mariotti,
• Lily D. Chambers,
• Massimo De Vittorio,
• William M. Megill and
• Francesco Rizzi

Beilstein J. Nanotechnol. 2019, 10, 32–46, doi:10.3762/bjnano.10.4

• stimuli. Inspired by the neuromasts found in the lateral line of fish, we present a novel flow sensor design based on two curved cantilevers with bending orientation antiparallel to each other. Antiparallel cantilever pairs were designed, fabricated and compared to a single cantilever based hair sensor in

• μV/(m s−1) for a higher air flow velocity range (between ±20–32 m s−1). The antiparallel cantilever design improves directional sensitivity and provides a sinusoidal response to flow angle. In forward flow, the single sensor reaches its saturation limitation, flattening at 67% of the ideal sinusoidal

• curve which is earlier than the antiparallel cantilevers at 75%. The antiparallel artificial hair sensor better compensates for temperature changes than the single sensor. Conclusion: This work demonstrated the successive improvement of the bidirectional sensitivity, that is, improved temperature

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• ], photocatalysts for rhodamine 6G dye degradation in aqueous solution [27] and were proposed as a thermal UV sensor for high-radiation environments [4]. Moreover, the ZTO materials were also employed as volatile organic compound (VOC) (such as methanol, ethanol or acetone vapors) sensors [28], as an anode for Li

A new bioinspired method for pressure and flow sensing based on the underwater air-retaining surface of the backswimmer Notonecta

• Matthias Mail,
• Adrian Klein,
• Horst Bleckmann,
• Anke Schmitz,
• Torsten Scherer,
• Peter T. Rühr,
• Goran Lovric,
• Robin Fröhlingsdorf,
• Stanislav N. Gorb and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2018, 9, 3039–3047, doi:10.3762/bjnano.9.282

• . Keywords: mechanoreceptor; Notonecta sensor; pressure sensor; Salvinia effect; superhydrophobic surfaces; Introduction The surfaces of animals and plants are interfaces between the organisms and the environment. Since animals and plants inhabit many different environments, it is not surprising that over

• mechanosensitive setae not only for drag reduction, but also for the detection of prey or predators. With one exception [16], the involvement of air layers in a sensory function has never been demonstrated. A possible principle for a sensor that uses an air layer for the detection of pressure changes is shown in

• a technical air-retaining surface and an optical sensor (for details see Experimental section). With this setup (Figure 8), which represents a biomimetic proof of principle, we were able to record the verbal conversation of two persons standing in front of the experimental tank. This was the final

Electrostatic force microscopy for the accurate characterization of interphases in nanocomposites

• Diana El Khoury,
• Richard Arinero,
• Jean-Charles Laurentie,
• Mikhaël Bechelany,
• Michel Ramonda and
• Jérôme Castellon

Beilstein J. Nanotechnol. 2018, 9, 2999–3012, doi:10.3762/bjnano.9.279

• , while exciting the probe at its first eigenmode f0 [58]. During the first scan, sample topography was extracted and collected on a first image using the tapping mode. For the second scan, the sensor was lifted by a known distance from the surface, the so-called “lift” distance, and controlled to follow

Size limits of magnetic-domain engineering in continuous in-plane exchange-bias prototype films

• Alexander Gaul,
• Daniel Emmrich,
• Timo Ueltzhöffer,
• Henning Huckfeldt,
• Hatice Doğanay,
• Johanna Hackl,
• Muhammad Imtiaz Khan,
• Daniel M. Gottlob,
• Gregor Hartmann,
• André Beyer,
• Dennis Holzinger,
• Slavomír Nemšák,
• Claus M. Schneider,
• Armin Gölzhäuser,
• Günter Reiss and
• Arno Ehresmann

Beilstein J. Nanotechnol. 2018, 9, 2968–2979, doi:10.3762/bjnano.9.276

• sensor applications [3][4][5], for stray field design [6][7] and particle transport in lab-on-chip systems [8][9][10][11], or in spintronics and magnonics [12][13][14]. Currently available techniques for domain patterning are either based on focused ion beams (FIB) [15][16][17], ion implantation [18][19

• ][20][21], laser annealing [22][23][24], thermally assisted scanning probe lithography [25], or a combination of spatially broad laser- or ion-beams and shadow masks [26][27][28][29][30]. Especially in magnonic [14] and sensor applications [4] in-plane magnetic domain patterns play a key role and are