Ultrasonication-assisted synthesis of CsPbBr₃ and Cs₄PbBr₆ perovskite nanocrystals and their reversible transformation

• Longshi Rao,
• Xinrui Ding,
• Xuewei Du,
• Guanwei Liang,
• Yong Tang,
• Kairui Tang and
• Jin Z. Zhang

Beilstein J. Nanotechnol. 2019, 10, 666–676, doi:10.3762/bjnano.10.66

• ; ultrasonication; Introduction Metal halide perovskite nanocrystals (PNCs) are promising candidates for application in the fields of light-emitting diodes (LEDs) [1][2], high-efficiency solar cells [3], low-threshold lasers [4], and photodetectors [5]. Compared to traditional semiconductors, colloidal PNCs

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

• depending on whether metallic nanotubes are above or below the percolation threshold [29][30]. In contrast, multiwall CNT mats always present a mild p-type semiconductor behavior which improves device to device reproducibility without the added burden of sorting nanotubes according to their metallic or

Choosing a substrate for the ion irradiation of two-dimensional materials

• Egor A. Kolesov

Beilstein J. Nanotechnol. 2019, 10, 531–539, doi:10.3762/bjnano.10.54

• (TMDs) due to the low displacement threshold barrier [18][19]. The latter is sufficient to create a considerable amount of defects – for example, through initiating a horizontal (in-plane) recoil cascade in a two-dimensional material, which is a chain of successive events of recoil atom energy transfer

• have close values, and therefore the curve components merge. In order to introduce defects into a two-dimensional material, sputtered substrate atoms and recoils reaching the interface need to have enough energy to pass the displacement threshold barrier which shows values from about 4 eV for chalcogen

• also increase the displacement threshold through creating a barrier for displaced atoms of the two-dimensional material, effectively making them “bounce back” after being displaced. For example, the threshold for graphene supported by a common SiO2 substrate increases to 68–196 eV [1], depending on the

Nanocomposite–parylene C thin films with high dielectric constant and low losses for future organic electronic devices

• Marwa Mokni,
• Gianluigi Maggioni,
• Abdelkader Kahouli,
• Sara M. Carturan,
• Walter Raniero and
• Alain Sylvestre

Beilstein J. Nanotechnol. 2019, 10, 428–441, doi:10.3762/bjnano.10.42

• polymers as gate dielectrics presents several advantages for the improvement of the electronic device properties such as higher dielectric constant [35] and dielectric strength [36], reduced threshold voltage [37], increased charge mobility and reduced leakage current [38]. Compared to pure parylene C and

Electromagnetic analysis of the lasing thresholds of hybrid plasmon modes of a silver tube nanolaser with active core and active shell

• Denys M. Natarov,
• Trevor M. Benson and
• Alexander I. Nosich

Beilstein J. Nanotechnol. 2019, 10, 294–304, doi:10.3762/bjnano.10.28

• 2RD, UK 10.3762/bjnano.10.28 Abstract Results from the electromagnetic modeling of the threshold conditions of hybrid plasmon modes of a laser based on a silver nanotube with an active core and covered with an active shell are presented. We study the modes of such a nanolaser that have their emission

• wavelengths in the visible-light range. Our analysis uses the mathematically grounded approach called the lasing eigenvalue problem (LEP) for the set of the Maxwell equations and the boundary and radiation conditions. As we study the modes exactly at the threshold, there is no need to invoke nonlinear and

• quantum models of lasing. Instead, we consider a laser as an open plasmonic resonator equipped with an active region. This allows us to assume that at threshold the natural-mode frequency is real-valued, according to the situation where the losses, in the metal and for the radiation, are exactly balanced

Uniform Sb₂S₃ optical coatings by chemical spray method

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Ilona Oja Acik,
• Arvo Mere and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 198–210, doi:10.3762/bjnano.10.18

• ratio exceed a critical value before or during process A, i.e., the energetic threshold for crystallization is surpassed. Absorption coefficient (α) vs wavelength of glass/ITO/TiO2/Sb2S3 samples incorporating as-deposited and vacuum treated (170 °C, 5 minutes) Sb2S3 layers. The α of glass/ITO/TiO2

Sputtering of silicon nanopowders by an argon cluster ion beam

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Zhenguo Wang,
• Wenbin Zuo,
• Sergey Belykh,
• Alexander Tolstogouzov,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2019, 10, 135–143, doi:10.3762/bjnano.10.13

• depth shows linear dependence on the cluster ion dose [8][12][13]. The energy dependence of the sputtering yield of Ag, Cu, Au, and Si exhibits a linear or ultralinear behavior [8][14][15]. In both cases, the energy threshold of 3–6 keV is observed. This value correlates with the surface binding energy

• the residual gas, E is the cluster energy, and Eth is the sputtering threshold energy. The threshold energy has been estimated to be about 6 keV. The same experimental data has also been fitted by the power function without incorporation of the threshold energy [34]: where N is the number of atoms in

• the cluster, A = 57 eV and q = 2.25 are the fitting parameters. At low energy, the denominator is close to 1 and the equation is simplified to The functional dependence in Equation 1 and Equation 3 is the same except for the presence of the threshold energy Eth in Equation 1. In general, the existence

New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water

• Emmanuel I. Unuabonah,
• Robert Nöske,
• Jens Weber,
• Christina Günter and
• Andreas Taubert

Beilstein J. Nanotechnol. 2019, 10, 119–131, doi:10.3762/bjnano.10.11

• synthesis temperature. Overall, nitrogen sorption analysis indicates that the porosity does not directly correlate with the synthesis conditions as soon as the threshold temperature of 500 °C is passed. As stated above, a high surface area is a key requirement for a material to work in water treatment. The

Threshold voltage decrease in a thermotropic nematic liquid crystal doped with graphene oxide flakes

• Mateusz Mrukiewicz,
• Krystian Kowiorski,
• Paweł Perkowski,
• Rafał Mazur and
• Małgorzata Djas

Beilstein J. Nanotechnol. 2019, 10, 71–78, doi:10.3762/bjnano.10.7

• /bjnano.10.7 Abstract We report a threshold voltage decrease in a nematic liquid crystal compound, 4-cyano-4′-pentylbiphenyl (5CB), doped with graphene oxide (GO) flakes at a concentration of 0.05–0.3 wt %. The threshold voltage decrease was observed at the same concentration in electro-optic and

• presence of the electric field was discussed. Keywords: graphene oxide; liquid crystal; nematic phase; switching; threshold voltage; Introduction Liquid crystals (LCs) are classified as a type of soft matter which are characterized by anisotropic molecules and a liquid-like fluidity behavior. Of all LC

• Frédericksz effect, the deformation of a homogeneous layer of a NLC is caused by the electric field E, which is initially perpendicular to the director. Such structural transition appears at a certain magnitude called the threshold voltage, Uth. When the applied voltage, U, is lower than the threshold U < Uth

Characterization and influence of hydroxyapatite nanopowders on living cells

• Przemyslaw Oberbek,
• Tomasz Bolek,
• Adrian Chlanda,
• Seishiro Hirano,
• Sylwia Kusnieruk,
• Julia Rogowska-Tylman,
• Ganna Nechyporenko,
• Viktor Zinchenko,
• Wojciech Swieszkowski and
• Tomasz Puzyn

Beilstein J. Nanotechnol. 2018, 9, 3079–3094, doi:10.3762/bjnano.9.286

• also shown relatively low cell viability results, but did not exceed the established toxicity threshold within the test concentration range. HApSA exhibits a toxic effect in the tested range only after having been doped with silicon. Only small differences between the GoHAP hydroxyapatites can be seen

• every figure, a blue line shows the level of control (100% of the living cells after 24 h) and the red line shows the toxicity threshold (50% of the living cells after 24 h). CLSM image of CHO cells and visible GoHAP90s (50 µg/mL) aggregates and agglomerates. A cell is visible a) during ) and b) after

Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics

• Franziska Ringleb,
• Stefan Andree,
• Berit Heidmann,
• Jörn Bonse,
• Katharina Eylers,
• Owen Ernst,
• Torsten Boeck,
• Martina Schmid and
• Jörg Krüger

Beilstein J. Nanotechnol. 2018, 9, 3025–3038, doi:10.3762/bjnano.9.281

• [22]. In a first set of experiments, LIFT of pure copper with varying layer thickness (10–100 nm) was investigated. The donor layers were irradiated by single pulses with fluences in the range of 0.8–7.8 J/cm2. The threshold for the LIFT decreases with decreasing copper layer thickness. In the case of

Hydrogen-induced plasticity in nanoporous palladium

• Markus Gößler,
• Eva-Maria Steyskal,
• Markus Stütz,
• Norbert Enzinger and
• Roland Würschum

Beilstein J. Nanotechnol. 2018, 9, 3013–3024, doi:10.3762/bjnano.9.280

• depletion of PdHα at a value below −0.99 V is consistent with values reported for palladium thin films [31][32]. The threshold values for the palladium hydride β-phase formation (−0.96 V) and the potential of α-phase depletion (−0.99 V) can be used for a phase distinction in current-controlled experiments

• formation threshold in the fifth loading cycle, which is marked as “onset of PdHβ” in Figure 5. The potential of PdHα depletion was crossed during the 11th loading cycle, which is also indicated in Figure 5. Both strain features present in potentiostatic experiments during desorption, namely the strain

• initiate deformation, this could explain the discrepancies between the mechanical performance of the two variants of npPd. In addition the contribution of dislocation plasticity is avoided when the phase transition proceeds fully coherently. Crossing the threshold potential of PdHβ-phase formation (−0.96 V

Site-controlled formation of single Si nanocrystals in a buried SiO₂ matrix using ion beam mixing

• Xiaomo Xu,
• Thomas Prüfer,
• Daniel Wolf,
• Hans-Jürgen Engelmann,
• Lothar Bischoff,
• René Hübner,
• Karl-Heinz Heinig,
• Wolfhard Möller,
• Stefan Facsko,
• Johannes von Borany and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2018, 9, 2883–2892, doi:10.3762/bjnano.9.267

• assumed to contribute whose start energy exceeds a displacement threshold of 8 eV. A more detailed discussion is given in Möller et al. [36]. The thermally activated phase separation process was simulated with a kinetic Monte Carlo (kMC) code [27]. Substrate preparation All substrates used in this study

Charged particle single nanometre manufacturing

• Philip D. Prewett,
• Cornelis W. Hagen,
• Claudia Lenk,
• Steve Lenk,
• Marcus Kaestner,
• Tzvetan Ivanov,
• Ahmad Ahmad,
• Ivo W. Rangelow,
• Xiaoqing Shi,
• Stuart A. Boden,
• Alex P. G. Robinson,
• Dongxu Yang,
• Sangeetha Hari,
• Marijke Scotuzzi and
• Ejaz Huq

Beilstein J. Nanotechnol. 2018, 9, 2855–2882, doi:10.3762/bjnano.9.266

• being the exposure dose required to clear out the resist from the centre of the doughnut due to the proximity effect, Qp being the threshold dose required for full clearance of the resist, R1 being the inner radius of the doughnut, α being the standard deviation of the forward-scattered deposited energy

Biomimetic surface structures in steel fabricated with femtosecond laser pulses: influence of laser rescanning on morphology and wettability

• Camilo Florian Baron,
• Alexandros Mimidis,
• Daniel Puerto,
• Evangelos Skoulas,
• Emmanuel Stratakis,
• Javier Solis and
• Jan Siegel

Beilstein J. Nanotechnol. 2018, 9, 2802–2812, doi:10.3762/bjnano.9.262

• below the single pulse ablation threshold, which we have determined experimentally as Fabl = 164 mJ/cm2 (following the method proposed by Liu in [38]). This indicates that the ablation is mediated by incubation and/or heat accumulation at the high repetition rate used [39][40] (a more detailed

Variation of the photoluminescence spectrum of InAs/GaAs heterostructures grown by ion-beam deposition

• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Eleonora M. Danilina and
• Sergei N. Chebotarev

Beilstein J. Nanotechnol. 2018, 9, 2794–2801, doi:10.3762/bjnano.9.261

• ][25]. But the IBD method differs from MBE. Therefore, it remains relevant to research the vertical stacking of QDs grown by using IBD. In the beginning, ST#1 samples were studied. The statistical analysis by the threshold tool in the Image Analysis 2.1.2 program showed that the density of QDs in the

Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

• Alexander Rostek,
• Marina Breisch,
• Kevin Pappert,
• Kateryna Loza,
• Marc Heggen,
• Manfred Köller,
• Christina Sengstock and
• Matthias Epple

Beilstein J. Nanotechnol. 2018, 9, 2763–2774, doi:10.3762/bjnano.9.258

• (Olympus MVX10, Olympus, Hamburg, Germany). The quantification of cell viability was performed by phase analysis (CellSens Dimensions, Olympus, Hamburg, Germany) of calcein-positive fluorescence signals calculating the fluorescent area. For calculating the phase analysis data, a threshold was set which

Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared

• Pavel Loiko,
• Tanujjal Bora,
• Josep Maria Serres,
• Haohai Yu,
• Magdalena Aguiló,
• Francesc Díaz,
• Uwe Griebner,
• Valentin Petrov,
• Xavier Mateos and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2018, 9, 2730–2740, doi:10.3762/bjnano.9.255

• output power of 221 mW at 1.942 µm with a slope efficiency η of 10% (with respect to the absorbed pump power Pabs), see Figure 5a,b. The laser threshold was at Pabs = 1.05 W. In the CW regime, the laser operated with higher efficiency, η of 56% and lower laser threshold of 0.70 W, so that the conversion

• average output power of 139 mW at 1.034 µm with η = 9%, as shown in Figure 6a,b. The laser threshold was at Pabs = 1.90 W. In the CW regime, the laser operated with higher η of 66% and ηconv was 14%. In the CW regime, a multi-peak emission at 1.035–1.040 µm was observed. These results correspond to the

Size-selected Fe₃O₄–Au hybrid nanoparticles for improved magnetism-based theranostics

• Maria V. Efremova,
• Yulia A. Nalench,
• Eirini Myrovali,
• Anastasiia S. Garanina,
• Ivan S. Grebennikov,
• Polina K. Gifer,
• Maxim A. Abakumov,
• Marina Spasova,
• Makis Angelakeris,
• Alexander G. Savchenko,
• Michael Farle,
• Natalia L. Klyachko,
• Alexander G. Majouga and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2018, 9, 2684–2699, doi:10.3762/bjnano.9.251

• the late stage of apoptosis. The two sets of experiments, direct AMF treatments and precultivation for 6 h, both show clear apoptosis/necrosis of 4T1 cells induced by the hyperthermia treatment. The more efficient precultivation might help to decrease the concentration threshold for MPH in future

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• topography images obtained after the scratching experiments. Figure 7b summarizes the scratching depth as a function of normal load. All samples get finally scratched when normal load reaches a certain threshold but this value is different for every material. After reaching this threshold, the scratching

• depth increases nearly linearly with normal load. Figure 7c condenses the scratching depth versus scratching distance. The scratching depth increases constantly for the sandfish scale, Teflon, and PMMA. For aluminium the chosen threshold (19.6 µN) was too small to obtain any wear, so the scratching

Enhancement of X-ray emission from nanocolloidal gold suspensions under double-pulse excitation

• Wei-Hung Hsu,
• Frances Camille P. Masim,
• Armandas Balčytis,
• Hsin-Hui Huang,
• Tetsu Yonezawa,
• Aleksandr A. Kuchmizhak,
• Saulius Juodkazis and
• Koji Hatanaka

Beilstein J. Nanotechnol. 2018, 9, 2609–2617, doi:10.3762/bjnano.9.242

• threshold of X-ray generation, which is obtained only under double-pulse irradiation. The delay of the main pulse relative to the pre-pulse, Δt, was controlled within three time zones: 0–5 ns (I), 5–10 ns (II) and 10–15 ns (III), which were set into the optical path of the pre-pulse. The optical delay for

• permittivity of material, ν is the electron–ion collision rate, ω is the optical cyclic frequency at the wavelength of excitation, ne,a,cr are the electron, atom and critical densities, respectively. The imaginary part of the permittivity is given by: The threshold fluence for water to reach the ENZ state can

• be calculated from the consideration that all absorbed energy density is converted to thermal energy of electrons. It can be calculated from the ablation threshold expression of a dielectric [37]: where ls = c/(κω) is the skin depth related to the imaginary part of the refractive index , c is the

Exploring the photoleakage current and photoinduced negative bias instability in amorphous InGaZnO thin-film transistors with various active layer thicknesses

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2018, 9, 2573–2580, doi:10.3762/bjnano.9.239

• works have highlighted that the electrical properties of the device (for both the initial and after stress conditions) such as threshold voltage, on/off ratio, and field effect mobility, can be effectively adjusted by controlling the active layer thickness [19][20][21][22][23]. Up to now, the impact of

• thicknesses were prepared by magnetron sputtering. The initial electrical properties and the photoleakage current of a-IGZO TFTs with various active layer thicknesses were investigated. The subthreshold value slightly increased while the threshold voltage (Vth) and mobility (μ) decreased with increasing TIGZO

• active layer thicknesses (TIGZO) measured at VDS = 20.1 V are shown in Figure 1b. Table 1 summarizes the electrical properties, such as field effect mobility in the saturation region (μsat), threshold voltage Vth (VGS at IDS of 1 nA), hysteresis of the transfer curves (the difference of VGS at IDS of 1

Cytotoxicity of doxorubicin-conjugated poly[N-(2-hydroxypropyl)methacrylamide]-modified γ-Fe₂O₃ nanoparticles towards human tumor cells

• Zdeněk Plichta,
• Yulia Kozak,
• Rostyslav Panchuk,
• Viktoria Sokolova,
• Matthias Epple,
• Lesya Kobylinska,
• Pavla Jendelová and
• Daniel Horák

Beilstein J. Nanotechnol. 2018, 9, 2533–2545, doi:10.3762/bjnano.9.236

• molecular weight of PHPMA can be kept below the renal threshold (Mw < 50 kDa), which allows for rapid renal clearance and avoids accumulation in the body. Indeed, the molecular weight of P(HPMA-MMAA) according to HPLC SEC chromatography was moderate (Mn = 33 kDa) with polydispersity index = 1.36. Formation

Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• (i) opposes the total driving force, so that Ffr(i) = −Fmot(i) , up to the threshold value Ffr(i) = µs(i) Fn(i). When this threshold is exceeded, a constant dynamic friction force with modulus Ffr(i) = µk(i) Fn(i) opposes the motion. Thus, Newton’s equation of motion for the block i can be written as

• velocity, and νc is the critical velocity for the transition [38]. This expression ensures that the value of the dynamic coefficient of friction is reached only when the sliding velocity is sufficiently high (i.e., ν >> νc). The static friction threshold is retrieved for ν = 0, so that the friction force

• shear stress is reached (i.e., the static friction threshold). The first detachment of the sliding surface produces a detachment avalanche propagating towards the region with higher static friction threshold, as shown in Figure 5 (see also Supporting Information File 1). Analogous effects on the

ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

• Marina Krasovska,
• Vjaceslavs Gerbreders,
• Irena Mihailova,
• Andrejs Ogurcovs,
• Eriks Sledevskis,
• Andrejs Gerbreders and
• Pavels Sarajevs

Beilstein J. Nanotechnol. 2018, 9, 2421–2431, doi:10.3762/bjnano.9.227

• was repeated with cadmium, where the same concentration of aqueous Cd(NO3)2 solution was used as a source of Cd2+ ions. The aqueous solutions of analytes were freshly prepared prior to measurement. In order to determine the sensor sensitivity threshold and quantify the change in ion concentration, a

• to 2 mM). The reduction peak current for the highest concentration can be explained by mass crystallization in the solution, in parallel with the sorption process. It is the threshold above which crystallites of lead oxides become visible on the ZnO nanostructured surface by SEM. In order to visually

• maximum concentration was chosen 10 and 100 times lower than CV sensitivity threshold of 1.5–3 mM. As shown in Figure 8, the DPV method is actually more sensitive than the CV method: using the same electrodes, it is possible to detect concentrations that are 100 times smaller than the CV sensitivity