Direct measurement of surface photovoltage by AC bias Kelvin probe force microscopy

• Masato Miyazaki,
• Yasuhiro Sugawara and
• Yan Jun Li

Beilstein J. Nanotechnol. 2022, 13, 712–720, doi:10.3762/bjnano.13.63

• [41][42][43][44]. Rutile TiO2 has a bandgap of 3.0 eV [45] and shows the SPV under UV illumination [46][47][48]. A clean rutile TiO2(110) surface (Crystal Base) was prepared by several cycles of Ar+ sputtering (1 keV, 1 × 10−6 Torr, 15 min) and annealing (993 K, less than 2 × 10−10 Torr, 30 min

• to ensure sufficient sensitivity (CPD ≈ 600 mV). Then we applied VAC, which was synchronized with the modulated laser, and measured the amplitude of that peak at 100 Hz depending on VAC (Figure 2c). The amplitude of the peak showed linear behavior as a function of VAC under UV illumination, which is

• consistent with Equation 12. While the x-intercept was 0 V in darkness, the x-intercept was 22.1 mV under UV illumination, at which VAC nullified the modulated frequency shift and the SPV value |VSPV| of 34.7 mV was determined from Equation 14. Therefore, when VAC was set to 22.1 mV, the peak at 100 Hz

A self-powered, flexible ultra-thin Si/ZnO nanowire photodetector as full-spectrum optical sensor and pyroelectric nanogenerator

• Liang Chen,
• Jianqi Dong,
• Miao He and
• Xingfu Wang

Beilstein J. Nanotechnol. 2020, 11, 1623–1630, doi:10.3762/bjnano.11.145

• systematically analyzed. The self-powered PDs exhibit high responsivity (1200 mA/W), high detectivity (1013 Jones) and fast response (τr = 18 μs, τf = 25 μs) under UV illumination. High and stable short-circuit output currents at each wavelength from ultraviolet (UV) to near-infrared (NIR) demonstrates that the

• -infrared (NIR) (1064 nm) under zero bias with fast response speed at each wavelength. The self-power PDs exhibit high responsivity (1200 mA/W), high detectivity (1013 Jones) and fast response speed (τr = 18 μs, τf = 25 μs) under UV illumination. The pyroelectric output current can drive a LED by harvesting

• significantly improved by reducing the thickness of Si [21]. In order to investigate the performance of self-powered PDs, a dynamic response curve I–t was measured under periodic 325 nm ultraviolet (UV) illumination and zero bias (Figure 1c). The photoresponsivity is calculated by Equation 1 [21]: where ipy

Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films

• Vadim Morari,
• Aida Pantazi,
• Nicolai Curmei,
• Vitalie Postolache,
• Emil V. Rusu,
• Marius Enachescu,
• Ion M. Tiginyanu and
• Veaceslav V. Ursaki

Beilstein J. Nanotechnol. 2020, 11, 899–910, doi:10.3762/bjnano.11.75

• temperature and b) at 20 K with a linear intensity axis. Current–voltage characteristics in dark and under UV illumination for a p-Si/n-Zn0.9Mg0.1O heterostructure plotted on linear (a), semi-logarithmic (b) and double logarithmic coordinates (c). Current–voltage characteristics in dark and under UV

• illumination for a p-Si/n-Zn0.6Mg0.4O heterostructure plotted on linear (a), semi-logarithmic (b) and double logarithmic coordinates (c). The PL band spectral position and the bandgap value for ZnMgO films at room temperature. The PL band spectral position and the bandgap value for ZnMgO films at 20 K. The

Rapid, ultraviolet-induced, reversibly switchable wettability of superhydrophobic/superhydrophilic surfaces

• Yunlu Pan,
• Wenting Kong,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 866–873, doi:10.3762/bjnano.10.87

• switching and extreme wettability changes upon ultraviolet (UV) illumination were investigated. TiO2 nanoparticles were modified in solutions of trimethoxy(alkyl)silane, and the suspensions were sprayed on glass substrates. For such samples, the water contact angle (WCA) was shown to transition from a

• superhydrophobic (WCA ≈ 165°) to a superhydrophilic (WCA ≈ 0°) state within 10 min upon UV illumination and subsequent recovery to superhydrophobicity occurred after heat treatment. It was found that the changes in the trimethoxy(alkyl)silane upon UV illumination can explain the rapid decrease of the WCA from more

• understanding, the effect of the trimethoxy(alkyl)silane concentration on the number of recycle cycles was investigated. Keywords: superhydrophilic surfaces; superhydrophobic surfaces; switchable wettability; TiO2; trimethoxy(alkyl)silane; UV illumination; Introduction Wettability is an important property of

Polydopamine-coated Au nanorods for targeted fluorescent cell imaging and photothermal therapy

• Boris N. Khlebtsov,
• Andrey M. Burov,
• Timofey E. Pylaev and
• Nikolai G. Khlebtsov

Beilstein J. Nanotechnol. 2019, 10, 794–803, doi:10.3762/bjnano.10.79

• ) Fluorescence spectra of 1.5 µM rhodamine 123 solution (curve 1) and AuNRs-PDA-R123-folate nanocomposite particles (curve 2). The inset shows a photo of cuvettes with as-prepared AuNRs, PDA-coated AuNRs, 1.5 µM rhodamine 123 solution, and AuNRs-PDA-R123-folate nanocomposite particles under UV illumination

Enhanced antineoplastic/therapeutic efficacy using 5-fluorouracil-loaded calcium phosphate nanoparticles

• Shanid Mohiyuddin,
• Saba Naqvi and
• Gopinath Packirisamy

Beilstein J. Nanotechnol. 2018, 9, 2499–2515, doi:10.3762/bjnano.9.233

Nanocellulose: Recent advances and its prospects in environmental remediation

• Katrina Pui Yee Shak,
• Yean Ling Pang and
• Shee Keat Mah

Beilstein J. Nanotechnol. 2018, 9, 2479–2498, doi:10.3762/bjnano.9.232

• species/sites, leading to a decrease in methanol reaction rate. Besides, Puls et al. [127] clarified that TiO2 could cause pitting on the surface of cellulose acetate/cellulose pulp fibres under UV illumination. Therefore, cellulose nanomaterials need to be coated and covered perfectly by inert UV

Self-assembled quasi-hexagonal arrays of gold nanoparticles with small gaps for surface-enhanced Raman spectroscopy

• Emre Gürdal,
• Simon Dickreuter,
• Fatima Noureddine,
• Pascal Bieschke,
• Dieter P. Kern and
• Monika Fleischer

Beilstein J. Nanotechnol. 2018, 9, 1977–1985, doi:10.3762/bjnano.9.188

• duration of the process [18]. A schematic overview of the fabrication process is shown in Figure 1. In a first step a silicon substrate is coated with gold-loaded polymer micelles (Figure 1a) via spin-coating. In a second step the micelles are exposed to deep UV illumination while the substrate is covered

• ED confirming that the micelles cover the entire silicon surface are shown in Figure 2a,b. The distribution is mostly regular, except for occasional defects, and shows a roughly hexagonal order. The center-to-center-spacing of the ordered particles amounts to 109 ± 20 nm. After deep UV illumination

• silicon substrate: (a) Gold nanoparticles with block copolymer micelles after spin-coating. (b) Deep UV illumination with water and a quartz glass on top of the substrate. (c) Electroless deposition. (d) Substrate after oxygen plasma, which removes the organic components. SEM images of the gold precursor

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

• Hana Krýsová,
• Josef Krýsa and
• Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

• observed at around −0.35 V (Figure 1a). In the applied potential range of 0.25–1.2 V there is a photocurrent plateau at ≈14 μA/cm2 at the UV illumination intensity applied (7.5 mW/cm2). For the deposition temperature of 450 °C, our titania films are photoactive already in the as-grown state (see Figure 1b

Optical orientation of nematic liquid crystal droplets via photoisomerization of an azodendrimer dopant

• Sergey A. Shvetsov,
• Alexander V. Emelyanenko,
• Natalia I. Boiko,
• Alexander S. Zolot'ko,
• Yan-Song Zhang,
• Jui-Hsiang Liu and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 870–879, doi:10.3762/bjnano.9.81

• conditions with glycerol (Figure 1b), and the droplet structure becomes almost homogeneous with the director being preferably oriented normally to the substrate and visualized as dark regions (Figure 3b). The UV illumination with λmax = 365 nm (or 384 nm) provides the boojum defect formation due to planar

Comparative study of antibacterial properties of polystyrene films with TiO_x and Cu nanoparticles fabricated using cluster beam technique

• Vladimir N. Popok,
• Cesarino M. Jeppesen,
• Peter Fojan,
• Anna Kuzminova,
• Jan Hanuš and
• Ondřej Kylián

Beilstein J. Nanotechnol. 2018, 9, 861–869, doi:10.3762/bjnano.9.80

• ], and they are also cheaper compared to silver. These particles mainly show bactericidal effects through mechanisms (i) and (iii). Among the metal oxides, TiO2 is the best-known and most widely used semiconductor material with a wide band gap that under UV illumination generates electron–hole pairs

• than 5%. Antibacterial tests The results of the antibacterial tests for the samples of type 1 are shown in Figure 5a. It can be seen that the amount of live cells is reduced by about 10–15% during the first 10 min upon UV illumination. Longer exposures of up to 120 min lead to a significant decrease of

• occur under longer UV illumination. For longer interaction times one should also consider the increasing coverage of NPs by dead cells, which impedes affecting the live cells. Thus, one can expect some kind of saturation in the antibacterial efficiency of our samples. UV light without the presence of

Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices

• T. Anh Thu Do,
• Truong Giang Ho,
• Thu Hoai Bui,
• Quang Ngan Pham,
• Hong Thai Giang,
• Thi Thu Do,
• Duc Van Nguyen and
• Dai Lam Tran

Beilstein J. Nanotechnol. 2018, 9, 771–779, doi:10.3762/bjnano.9.70

• on the surface of ZnO sub-micrometer spheres due to the photogenerated electrons from ZnO under UV illumination that reacted with AuCl4− ions. Figure 2a shows the high-resolution TEM images of Au NPs incorporated in ZnO at different magnifications. The observed size distribution of the Au NPs is in

Light-induced magnetoresistance in solution-processed planar hybrid devices measured under ambient conditions

• Sreetama Banerjee,
• Daniel Bülz,
• Danny Reuter,
• Karla Hiller,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2017, 8, 1502–1507, doi:10.3762/bjnano.8.150

• exposure to ambient under UV illumination leads to a reaction, most probably with singlet oxygen and/or ozone [15]. As the magnetoresistance measurements are performed in presence of white light with a spectrum ranging from 400 to 700 nm, we believe that different parts of the wavelength spectra can have

CVD transfer-free graphene for sensing applications

• Chiara Schiattarella,
• Sten Vollebregt,
• Tiziana Polichetti,
• Brigida Alfano,
• Ettore Massera,
• Maria Lucia Miglietta,
• Girolamo Di Francia and
• Pasqualina Maria Sarro

Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102

• electronics, able to perform data analysis [8] or a refresh of the device through UV illumination or thermal annealing [9][10][11][12][13]. All that said, the development of new approaches enabling the direct growth of large-area graphene layers on arbitrary insulating substrates, compatible with conventional

High photocatalytic activity of Fe₂O₃/TiO₂ nanocomposites prepared by photodeposition for degradation of 2,4-dichlorophenoxyacetic acid

• Shu Chin Lee,
• Hendrik O. Lintang and
• Leny Yuliati

Beilstein J. Nanotechnol. 2017, 8, 915–926, doi:10.3762/bjnano.8.93

• of the TiO2. With increased loading of Fe2O3, the photocatalytic performance of TiO2 in fact decreased. As another control experiment, α-Fe2O3 synthesized at 500 °C for 4 h was also tested for the removal of 2,4-D. The removal of 2,4-D using α-Fe2O3 was only 2% after 1 h of UV illumination, which

• -butanol has fast reaction with hydroxyl radicals [27][40] and hence, they were selected for the scavenger studies. As shown in Figure 7, the photocatalytic reactions under 1 h of UV illumination were evaluated in the presence of each scavenger on the unmodified TiO2 (NT) and the Fe2O3(0.5)/TiO2 (PD). For

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

Graphene functionalised by laser-ablated V₂O₅ for a highly sensitive NH₃ sensor

• Margus Kodu,
• Artjom Berholts,
• Tauno Kahro,
• Mati Kook,
• Peeter Ritslaid,
• Helina Seemen,
• Tea Avarmaa,
• Harry Alles and
• Raivo Jaaniso

Beilstein J. Nanotechnol. 2017, 8, 571–578, doi:10.3762/bjnano.8.61

• clearly observed for single-layer graphene functionalised by a thin layer of laser-deposited ZrO2 or Ag. First, under UV exposure, the sensor responses were at least 2 to 3 times faster. Second, without UV illumination, the recovery of the signal in pure air was almost absent in the case of ZrO2, and only

• and NH3 gases. The measurements were performed at room temperature under UV illumination. The horizontal bars indicate the time intervals of gas exposure. The inset depicts a response to 100 ppm CO gas. Response of the graphene sensor to different concentrations of NH3 gas before (dashed line) and

• after (solid line) PLD functionalisation, measured under UV illumination at the room temperature. The grey bars indicate the duration of gas exposure for the given concentration. Photograph of a gas sensor device based on PLD-functionalised CVD graphene. The gap between the electrodes is 1 × 4 mm2. The

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

• . The phenol photolysis degree under visible light in the presence of S3 and S4 films (with TiO2 and Fe2O3 NPs) is about 80% and 83%, respectively (Figure 7c). This means that the photodecomposition of phenol is similarly effective as under UV illumination if a proper catalyst is used. The apparent rate

• hydroquinone (λ = 292 nm) is reduced by 51%, and in the spectrum appears a new well-defined band at 260 nm, characteristic to p-benzoquinone. This finding suggests that 51% of hydroquinone is oxidized to p-benzoquinone in the first 5 min of UV illumination, and the two compounds (hydroquinone and p

Facile fabrication of luminescent organic dots by thermolysis of citric acid in urea melt, and their use for cell staining and polyelectrolyte microcapsule labelling

• Nadezhda M. Zholobak,
• Anton L. Popov,
• Alexander B. Shcherbakov,
• Nelly R. Popova,
• Mykhailo M. Guzyk,
• Valeriy P. Antonovich,
• Alla V. Yegorova,
• Yuliya V. Scrypynets,
• Inna I. Leonenko,
• Alexander Ye. Baranchikov and
• Vladimir K. Ivanov

Beilstein J. Nanotechnol. 2016, 7, 1905–1917, doi:10.3762/bjnano.7.182

• O-dot formation is represented in Scheme 1, which also demonstrates the appearance of 0.01% O-dots solution under UV illumination. The formation of a fluorescent O-dot requires the presence not only of primary fluorophores, but also of a binder joining them together, for instance, the products of

• -polyelectrolyte deposition, decoration with O-dots and subsequent CaCO3-core decomposition. Left: Possible mechanism of O-dot formation. Right: Appearance of 0.01% O-dots colloidal solution under UV illumination. Supporting Information Supporting Information File 184: Additional pictures and experimental data

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• conduction through metallic MWCNTs (Figure 5a). No influence of the concentration of HfO2 NPs decorating the MWCNTs is noticed in the dark I–V curves. UV illumination (365 nm) also has no detectable effect on bare MWCNTs. Although it was reported that MWCNTs generate a photocurrent [62], this effect is

• O2− states in HfO2 and thus supporting the metallic nature of the MWCNTs. For the MWCNT:HfO2 hybrid material, a clear shift of the I–V curve is observed in Figure 5a upon UV illumination. In the present experiment, the short-circuit current (ISC) is 0.7 µA and the open-circuit voltage (Voc) is −12 mV

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• current of the sensor at a bias voltage of 10 or 5 V was recorded. A UV light-emitting diode (310 nm at 0.3 mW·cm−2) was placed above the sensor for UV-assisted sensing. Two sensing modes were applied. For the first, called UV-activation mode, the sensor was under constant UV illumination through the

• negatively charged by catching electrons. The conductance of the ND with NO (or O2) adsorption is thus smaller than that in the pristine state of the ND (i.e., without adsorbed molecules). Under UV illumination, the ND conductance becomes larger since the adsorbed NO (or O2) molecules are neutralized by

• again by molecular adsorption and desorption. In the UV-activation mode, the adsorption and desorption of NO molecules rapidly reach a dynamic equilibrium under UV illumination during NO exposure. In the UV-recovery mode, it takes much longer time to reach full adsorption during NO exposure. Therefore

Impact of ultrasonic dispersion on the photocatalytic activity of titania aggregates

• Hoai Nga Le,
• Frank Babick,
• Klaus Kühn,
• Minh Tan Nguyen,
• Michael Stintz and
• Gianaurelio Cuniberti

Beilstein J. Nanotechnol. 2015, 6, 2423–2430, doi:10.3762/bjnano.6.250

• dispersion. The photocatalytic activity was examined by the color removal of methylene blue (MB) with a laboratory-scale setup based on a plug flow reactor (PFR) and planar UV illumination. The process parameters such as flow regime, optical path length and UV intensity are well-defined and can be varied

• procedures between different laboratories. The central part of the paper was the study of the discoloration of MB in the presence of P25 under UV illumination. The size of the aggregates appeared to have only a minor influence on the intrinsic reaction rate constant, even though the efficiency of photon

Novel ZnO:Ag nanocomposites induce significant oxidative stress in human fibroblast malignant melanoma (Ht144) cells

• Syeda Arooj,
• Samina Nazir,
• Akhtar Nadhman,
• Nafees Ahmad,
• Bakhtiar Muhammad,
• Ishaq Ahmad,
• Kehkashan Mazhar and
• Rashda Abbasi

Beilstein J. Nanotechnol. 2015, 6, 570–582, doi:10.3762/bjnano.6.59

• differential cytotoxicity in cancer versus normal cells. A recent study by Ismail et al. [31] reported ZnO:Ag NPs (IC50 values 45.10) as cytotoxic to HepG2 cells under UV illumination; however, their effect was similar to the effect of ZnO-NPs (IC50 values 42.60) under the same conditions. The authors however

Synthesis of radioactively labelled CdSe/CdS/ZnS quantum dots for in vivo experiments

• Gordon M. Stachowski,
• Christoph Bauer,
• Christian Waurisch,
• Denise Bargheer,
• Peter Nielsen,
• Jörg Heeren,
• Stephen G. Hickey and
• Alexander Eychmüller

Beilstein J. Nanotechnol. 2014, 5, 2383–2387, doi:10.3762/bjnano.5.247

• of CdSe/CdS QDs with a radioactive 65ZnS shell using a modified, operator-safe, SILAR procedure is presented. Under UV illumination, no difference in the photoluminescence of the radioactive and non-radioactive CdSe/CdS/ZnS colloidal solutions was observed. Furthermore, a down-scaled synthesis for

• safety issues, spectra could not be taken for the CdSe/CdS/65ZnS/ZnS QDs. However, the PL of both the cleaned CdSe/CdS/ZnS and the CdSe/CdS/65ZnS/ZnS QDs show no significant difference under UV illumination (Figure 1C) with the PL remaining unchanged even after one month. The radiation due to the 65Zn

• . Therefore, an encapsulation and phase transfer method described by Shtykova et al. was used to introduce the QDs, stabilized by nonpolar ligands, into an amphiphilic polymer [14]. Under UV illumination, similar emission colours for both, the hydrophilic, encapsulated and the hydrophobic QDs were detected

Low cost, p-ZnO/n-Si, rectifying, nano heterojunction diode: Fabrication and electrical characterization

• Vinay Kabra,
• Lubna Aamir and
• M. M. Malik

Beilstein J. Nanotechnol. 2014, 5, 2216–2221, doi:10.3762/bjnano.5.230

• an n-Si substrate using a dip coating technique. The device was then characterized by current–voltage (I–V) and capacitance–voltage (C–V) measurements. The effect of UV illumination on the I–V characteristics was also explored and indicated the formation of a highly rectifying, nano heterojunction

• with a rectification ratio of 101 at 3 V, which increased nearly 2.5 times (232 at 3 V) under UV illumination. However, the cut-in voltage decreases from 1.5 V to 0.9 V under UV illumination. The fabricated device could be used in switches, rectifiers, clipper and clamper circuits, BJTs, MOSFETs and

• other electronic circuitry. Keywords: capacitance–voltage measurements; current–voltage measurement; solution-processed rectifying p-ZnO/n-Si heterojunction diode; UV illumination; Introduction The fabrication of homo- and hetero-junction diodes based on nanomaterials is an emerging field that could