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

• elastic constant [19][20][21]. In this work, we discuss our approach in reducing the threshold voltage by using graphene oxide (GO) flakes. The extraordinary properties of GO make this material a good candidate for this purpose. GO is an oxidized form of graphene [22][23][24]. In GO, carbon atoms are

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

• values. A clear optical behavior influence of the presence of carbon layers on tin dioxide can be observed for the SnO2@C and SnO2@SiO2@C nanostructured microspheres (C symbolizing here reduced graphene oxide, rGO) reported in [53], where the UV–vis spectra show a clear increase in absorbance (mostly in

Co-intercalated layered double hydroxides as thermal and photo-oxidation stabilizers for polypropylene

• Qian Zhang,
• Qiyu Gu,
• Fabrice Leroux,
• Pinggui Tang,
• Dianqing Li and
• Yongjun Feng

Beilstein J. Nanotechnol. 2018, 9, 2980–2988, doi:10.3762/bjnano.9.277

• functional additives have attracted increasing attention for their wide applications in polymers [7]. Organic anti-aging species have been immobilized onto inorganic supports (e.g., carbon nanotubes, SiO2, graphene oxide) to produce inorganic–organic composites with higher migration resistance [8][9][10

Ternary nanocomposites of reduced graphene oxide, polyaniline and hexaniobate: hierarchical architecture and high polaron formation

• Claudio H. B. Silva,
• Maria Iliut,
• Christopher Muryn,
• Christian Berger,
• Zachary Coldrick,
• Vera R. L. Constantino,
• Marcia L. A. Temperini and
• Aravind Vijayaraghavan

Beilstein J. Nanotechnol. 2018, 9, 2936–2946, doi:10.3762/bjnano.9.272

• nanocomposite composed of polyaniline (PANI), reduced graphene oxide (rGO) and hexaniobate (hexNb) nanoscrolls. Atomic force microscopy images show an interesting architecture of rGO flakes coated with PANI and decorated by hexNb. Such features are attributed to the high stability of the rGO flakes prepared at

• morphological aspects. Therefore, the new nanocomposite presents promising properties for development of new materials in the film form on substrates for sensing or corrosion protection for example. Keywords: graphene oxide; hexaniobate; polyaniline; Raman spectroscopy; secondary doping; Introduction

• bipolaronic to polaronic segments compared to the neat polymer and a superior thermal stability (the doped form of PANI is observed even after heating at 150 °C for 90 min). The literature has shown that PANI and reduced graphene oxide (rGO) show enhanced properties when combined at the nanoscale domain and

Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• for semiconductor gas sensors [6]. Graphene oxide (GO), as a derivative of graphene, is prepared via the oxidation of graphene. Epoxy groups, hydroxy groups and defects are produced at the surface when oxidizing graphene [7][8][9][10]. These variations will alter the electronic structure of graphene

• -sensing material. Therefore, further reduction of GO is necessary and the product after reduction is called reduced graphene oxide (rGO). Some oxygen functional groups remain after the reduction, some defects and vacancies are generated during the reduction, which are beneficial for the gas adsorption [13

• of semiconductor interfaces Reduced graphene oxide (rGO), which plays the role of a p-type semiconductor, can form heterojunctions when forming composites with most metal-oxide semiconductors. In the example of a SnO2–rGO sensor [45], SnO2 and rGO formed p–n heterojunctions. The enhancement mechanism

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

• ” saturable absorbers (SAs) for lasers operating in the passively Q-switched (PQS) and mode-locked regimes. These include carbon nanostructures (e.g., graphene, graphene oxide, graphite nanoparticles, single-walled carbon nanotubes (SWCNTs)) [12][13][14][15], few-layer transition metal dichalcogenides (TMDs

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

• nanostructures in the form of thin film, membrane, fibre and hybrid materials under UV and visible light irradiation. Nanocellulose–metal oxide (TiO2, ZnO, graphene oxide, and Fe2O3) composites have been used as photocatalysts to improve the degradation rate of organic pollutants as compared to individual

• synergistic effect that enhanced the catalytic performance of the individual materials. Besides, Pastrana-Martínez et al. [124] observed that three photocatalysts, i.e., commercial TiO2 P25, lab-made TiO2, and graphene oxide doped TiO2 (GO-TiO2), which were assembled on flat sheet cellulose membranes

Nanotribology

• Enrico Gnecco,
• Susan Perkin,
• Andrea Vanossi and
• Ernst Meyer

Beilstein J. Nanotechnol. 2018, 9, 2330–2331, doi:10.3762/bjnano.9.217

• including nanodiamonds [1] and novel materials such as nitrogen-doped graphene oxide [2] and imidazolium-based ionic liquids [3] used as additives to mineral oils. Standard large-scale applications to steel surfaces, but also to a material of key importance in micro- and nanoelecromechanical systems, i.e

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• polyurethane (PU) nanofibers using electrospinning [64]. These nanoparticles embedded in polymer nanofibers could be promising materials for room temperature gas sensing. Furthermore, graphene oxide (GO) sheets have also been incorporated with electrospun polyacrylonitrile (PAN) fibers [65][66][67]. The fibers

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

• Mattia Scardamaglia and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

• -sensitized solar cells [67]. A high-performance anode material for lithium-ion batteries was obtained using graphene co-doped with nitrogen and fluorine, which was prepared by a hydrothermal reaction of an aqueous dispersion of graphene oxide with trimethylamine trihydrofluoride [68]. In nitrogen-doped

• underwent different temperature treatments, yielding different surface compositions of nitrogen functionalities, as observed by XPS [114]. They produced N-graphene either by the annealing of graphene oxide (GO) in NH3 or by annealing a composite of N-containing polymer (polyaniline or polypyrrole) and rGO

SO₂ gas adsorption on carbon nanomaterials: a comparative study

• Deepu J. Babu,
• Divya Puthusseri,
• Frank G. Kühl,
• Sherif Okeil,
• Michael Bruns,
• Manfred Hampe and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 1782–1792, doi:10.3762/bjnano.9.169

• -walled carbon nanotubes (SWNTs) and vertically aligned carbon nanotubes (VACNTs) are investigated and compared against the adsorption characteristics of activated carbon and graphene oxide (GO). A comprehensive overview of the adsorption behavior of this family of carbon adsorbents is given for the first

• nanohorns (CNHs), graphene and graphene oxide were discovered. Unlike activated carbon, these nanomaterials have a defined geometry with distinct pore structure. Sun et al. investigated the SO2 adsorption characteristics of SWNTs, MWNTs and activated carbon at atmospheric pressure and at very low SO2

• -graphene layers [18]. With this morphology it represents a typological carbon adsorbent with extended structural disorder. Graphene oxide (GO) has a 2D layered structure as shown schematically in Figure 1b. The starting material for the synthesis of GO is graphite, the oxidation of which introduces oxygen

Sheet-on-belt branched TiO₂(B)/rGO powders with enhanced photocatalytic activity

• Huan Xing,
• Wei Wen and
• Jin-Ming Wu

Beilstein J. Nanotechnol. 2018, 9, 1550–1557, doi:10.3762/bjnano.9.146

• -on-belt branched TiO2(B) powder was synthesized with the simultaneous incorporation of reduced graphene oxide (rGO). The monophase, hierarchically nanostructured TiO2(B) exhibited a reaction rate constant 1.7 times that of TiO2(B)/rGO and 2.9 times that of pristine TiO2(B) nanobelts when utilized to

• assist the photodegradation of phenol in water under UV light illumination. The enhanced photocatalytic activity can be attributed to the significantly increased surface area and enhanced charge separation. Keywords: branched nanostructure; photocatalysis; reduced graphene oxide; TiO2(B); Introduction

• harvesting efficiency, which also contributes to increased photocatalytic activity [22][27]. Herein, we report a novel approach to synthesize branched TiO2(B) nanobelts incorporated at the same time with reduced graphene oxide (rGO). The unique sheet-on-belt nanostructure demonstrates a high specific surface

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• six sections. The optical and electrochemical characteristics of modified TiO2 photocatalysts are discussed in the first section. In the second section, we have reviewed how carbon-based advanced materials like reduced graphene oxide (RGO), carbon nanotubes (CNTs) and carbon dots (CDs) improve the

• TiO2 are listed in Table 1. Photocatalytic reduction of Cr(VI) over reduced graphene oxide modified TiO2 Graphene is a single layer of two-dimensional carbon material with graphite structure. Because of its low cost, excellent conductivity, superior chemical stability and exceptionally high specific

• with visible light, in the second step. Third step involves either release of Cr(III) species into the solution due to their electrostatic repulsion from the protonated surfaces of TiO2–RGO or their adsorption by deprotonated surfaces. Li et al. fabricated a composite of TiO2 and reduced graphene oxide

Electrodeposition of reduced graphene oxide with chitosan based on the coordination deposition method

• Mingyang Liu,
• Yanjun Chen,
• Chaoran Qin,
• Zheng Zhang,
• Shuai Ma,
• Xiuru Cai,
• Xueqian Li and
• Yifeng Wang

Beilstein J. Nanotechnol. 2018, 9, 1200–1210, doi:10.3762/bjnano.9.111

• attention due to its appealing applications for sensors, supercapacitors and lithium-ion batteries. However, there are still some limitations in the current electrodeposition methods for graphene. Here, we present a novel electrodeposition method for the direct deposition of reduced graphene oxide (rGO

• , which can then be used for electrochemical detection. Keywords: chitosan; coordination; electrodeposition; nanocomposite films; reduced graphene oxide; Introduction Graphene has attracted tremendous attention due to its large surface area, excellent mechanical strength, high electronic conductivity

• and good adsorption capacity [1][2].Graphene has a diverse range of applications in solar cells, hydrogen storage materials, electroluminescent devices and electrode materials [3][4][5]. In particular, graphene or reduced graphene oxide (rGO) and biopolymer (e.g., gellan gum, chitosan, and alginate

Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• (EFM) phase with high resolution as a function of the electrical direct current bias applied either to the probe or sample. Based on the dielectric constant difference of graphene oxide (GO) sheets (reduced using various methods), EFS can be used to characterize the degree of reduction of uniformly

• reduced one-atom-thick GO sheets at the nanoscale. In this paper, using thermally or chemically reduced individual GO sheets on mica substrates as examples, we characterize their degree of reduction at the nanoscale using EFS. For the reduced graphene oxide (rGO) sheets with a given degree of reduction

• ; electrostatic force microscopy; electrostatic force spectroscopy; graphene oxide; Introduction Graphene is a two dimensional (2D) crystal with superior mechanical [1], thermal [2], electrical [3][4] and optical [5] properties. It can be produced using graphene oxide (GO) as a precursor through cost-effective

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar

• : adhesion; atomic force microscopy (AFM); graphene oxide (GO); nanoscale dielectric properties; reduced graphene oxide (RGO); Introduction The local dielectric distribution is a key factor that influences the physical properties and functionalities of various materials such as polymer nanocomposites [1][2

• samples [39] or lifting of the AFM tip to scan for a second time [40], which may result in a lower spatial resolution. The method was validated by local dielectric mapping of graphene oxide (GO) and reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric

Graphene composites with dental and biomedical applicability

• Sharali Malik,
• Felicite M. Ruddock,
• Adam H. Dowling,
• Kevin Byrne,
• Wolfgang Schmitt,
• Ivan Khalakhan,
• Yoshihiro Nemoto,
• Hongxuan Guo,
• Lok Kumar Shrestha,
• Katsuhiko Ariga and
• Jonathan P. Hill

Beilstein J. Nanotechnol. 2018, 9, 801–808, doi:10.3762/bjnano.9.73

• materials. They must be compatible with oral fluids, must not release toxic products into the oral location and must have sufficient strength and durability to be fit for purpose [4]. Most other studies of graphene-dental polymer materials have used graphene oxide (GO) [5] which may be cytotoxic [6][7

• rather than graphene oxide [14][15]. FLG-dental polymers Six types of FLG-dental polymers were made up; one control plus five with different loadings of graphene. Figure 3 shows FLG-polymer A (lowest concentration of FLG) and FLG-polymer E (highest concentration of FLG used), hence E appears much darker

A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide

• Shahreen Binti Izwan Anthonysamy,
• Syahidah Binti Afandi,
• Mehrnoush Khavarian and
• Abdul Rahman Bin Mohamed

Beilstein J. Nanotechnol. 2018, 9, 740–761, doi:10.3762/bjnano.9.68

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• photoreduction of graphene oxide (GO) to graphene or reduced graphene oxide (rGO) by Wu et al. Their study revealed the photocatalytic Ag NP reduction at λ > 390 nm [95]. The schematic diagram representing the interaction of GO with Ag is shown in Figure 8. The LSPR effect on the Ag NPs generated a strong

Anchoring Fe₃O₄ nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating

• Błażej Scheibe,
• Radosław Mrówczyński,
• Natalia Michalak,
• Karol Załęski,
• Michał Matczak,
• Mateusz Kempiński,
• Zuzanna Pietralik,
• Mikołaj Lewandowski,
• Stefan Jurga and
• Feliks Stobiecki

Beilstein J. Nanotechnol. 2018, 9, 591–601, doi:10.3762/bjnano.9.55

• Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland 10.3762/bjnano.9.55 Abstract Reduced graphene oxide–magnetite hybrid aerogels attract great interest thanks to their potential applications, e.g., as

• magnetic actuators. However, the tendency of magnetite particles to migrate within the matrix and, ultimately, escape from the aerogel structure, remains a technological challenge. In this article we show that coating magnetite particles with polydopamine anchors them on graphene oxide defects

• ; polydopamine; reduced graphene oxide; Introduction Preparation of hybrid aerogels based on two-dimensional carbon nanomaterials with unique physicochemical properties is among the most popular recent nanotechnological trends [1]. With this respect, graphene oxide (GO) is one of the most exploited aerogel

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

• Nagamalai Vasimalai,
• Vânia Vilas-Boas,
• Juan Gallo,
• María de Fátima Cerqueira,
• Mario Menéndez-Miranda,
• José Manuel Costa-Fernández,
• Lorena Diéguez,
• Begoña Espiña and
• María Teresa Fernández-Argüelles

Beilstein J. Nanotechnol. 2018, 9, 530–544, doi:10.3762/bjnano.9.51

• characteristic peaks of graphene oxide [42][43][44], and they are also in agreement with the HR-TEM lattice distances measured. FTIR spectroscopy of the synthesized C-dots confirms the presence of different functional groups in each sample depending on the starting material. The FTIR spectrum of cinnamon C-dots

Ultralight super-hydrophobic carbon aerogels based on cellulose nanofibers/poly(vinyl alcohol)/graphene oxide (CNFs/PVA/GO) for highly effective oil–water separation

• Zhaoyang Xu,
• Huan Zhou,
• Sicong Tan,
• Xiangdong Jiang,
• Weibing Wu,
• Jiangtao Shi and
• Peng Chen

Beilstein J. Nanotechnol. 2018, 9, 508–519, doi:10.3762/bjnano.9.49

• 10.3762/bjnano.9.49 Abstract With the worsening of the oil-product pollution problem, oil–water separation has attracted increased attention in recent years. In this study, a porous three-dimensional (3D) carbon aerogel based on cellulose nanofibers (CNFs), poly(vinyl alcohol) (PVA) and graphene oxide (GO

• facile preparation process of carbon aerogels, these materials are viable candidates for use in oil–water separation and environmental protection. Keywords: 3D network structure; carbon aerogel; cellulose nanofibers; graphene oxide; oil absorption; poly(vinyl alcohol); Introduction In recent years, oil

• to remove the excess metal ions. After the chemical treatment, the slurry of 1 wt % purified cellulose was ground by a grinder to obtain a CNF slurry [46]. Preparation of graphene oxide GO was synthesized from graphite powder using a modified Hummers’ method [47][48]. The fabrication process was

Blister formation during graphite surface oxidation by Hummers’ method

• Olga V. Sinitsyna,
• Georgy B. Meshkov,
• Anastasija V. Grigorieva,
• Alexander A. Antonov,
• Inna G. Grigorieva and
• Igor V. Yaminsky

Beilstein J. Nanotechnol. 2018, 9, 407–414, doi:10.3762/bjnano.9.40

• microscopy (AFM); graphene; graphite intercalation compounds (GICs); graphite oxide (GO); highly annealed pyrolythic graphite (HAPG); Introduction Graphite oxide (GO) and its single-layer derivative, graphene oxide, are of great importance due to their potential applications as a part of supercapacitors

• , lithium-ion batteries, catalysts, systems for water pollution treatment, nonlinear optical devices and sensors [1][2][3][4]. One of the most important applications of graphene oxide is the synthesis of reduced graphene oxide, which exhibits properties similar to graphene [4][5]. The formation of GO

• to note that a similar surface relief was observed in [23] for graphene oxide obtained by Hummers’ method. Most likely, graphene oxide inherits the microstructure from an intermediate GIC. Particular attention was paid to regions containing bunches of the cleavage steps (Figure 8). Some steps became

BN/Ag hybrid nanomaterials with petal-like surfaces as catalysts and antibacterial agents

• Konstantin L. Firestein,
• Denis V. Leybo,
• Alexander E. Steinman,
• Andrey M. Kovalskii,
• Andrei T. Matveev,
• Anton M. Manakhov,
• Irina V. Sukhorukova,
• Pavel V. Slukin,
• Nadezda K. Fursova,
• Sergey G. Ignatov,
• Dmitri V. Golberg and
• Dmitry V. Shtansky

Beilstein J. Nanotechnol. 2018, 9, 250–261, doi:10.3762/bjnano.9.27

• only improve the colloidal stability of Ag NPs but also improve their antibacterial characteristics. A wide range of materials, such as graphene oxide [30][31], carbon nanotubes [32], SiO2 [33], Fe3O4 [34], ZnO [35], CuO [36], TiO2 [37] and others, have been tested as the supports for Ag NPs. Compared

Advances in nanocarbon composite materials

• Sharali Malik,
• Arkady V. Krasheninnikov and
• Silvia Marchesan

Beilstein J. Nanotechnol. 2018, 9, 20–21, doi:10.3762/bjnano.9.3

• , Moldova, Korea, China, Japan, Australia and New Zealand. This Thematic Series highlights virtually all subfields of advanced nanocarbon materials research, from the longer established fields of carbon nanofibers, graphene oxide (GO) and multiwalled carbon nanotubes (MWCNTs) in composite materials, to the