Dinesh PRATAP Singh

University of Santiago of Chile (USACH) · Physics Department

Graphene is a highly versatile two-dimensional carbon-based material employed in several research areas having progressive characteristics comprising properties like high surface area, transport, thermal, optical, elasticity, strength etc. Graphene-based composite materials are considered to be potentially smart candidates for various biomedical ap...

Nickel doped cadmium sulfide (Ni:CdS) thin films are deposited onto glass and FTO substrate using spray pyrolysis technique. The effect of annealing temperature on the thin films and its morphological, microstructural, optical dispersion, linear-nonlinear and electrical, properties are extensively investigated by using various techniques such as fi...

Metal-organic frameworks (MOFs) have emerged as candidate materials for nonlinear optics due to their enhanced optical and chemical stability in comparison with conventional organic crystals. However, producing large single crystals that support perfect phase matching conditions for frequency conversion is a long-standing challenge due to the highl...

Determining the electron field emission (FE) turn-on field of the silicon nanowires(SiNWs) array can better adapt to the application of field-assisted photocathode. Here, we report the observations of FE from SiNWs grown on n-type Si(100) by utilizing silver induce chemical etching (SICE) approach. The growth of SiNWs is confirmed by XPS and XRD sp...

Our environment is greatly endangered by the accumulation of various toxic organic pollutants that are continually produced through unavoidable human needs and the industrialization process. Herein, we report highly active gold nanoparticles (AuNPs) immobilized on two-dimensional (2D) TiO2 nanosheets (AuNPs-TiO2NSs) as a catalyst for the catalytic...

This paper presents a study of the complex permittivity of n - type copper indium selenide semiconductor compound at low temperatures down to −175 °C. Alternating current with frequency varying between 20 Hz and 1 MHz is applied to the material in order to measure the dielectric constant ɛ ′ and dielectric loss D = ɛ ″/ ɛ ′. ɛ ′ is found to decreas...

In this work, we report the synthesis of TiO2 nanotubes encapsulated platinum nanoparticles (PtNPs-TiO2NTs) as a highly efficient catalyst for the catalytic reduction of azure B (AZB) dye in the sodium borohydride (NaBH4) medium. The encapsulation of PtNPs (particle size ∼ 2–3 nm) inside the TiO2NTs was confirmed by HR-TEM analysis. The as-prepared...

Here we report the deposition of Cu2S/CdS thin-film on FTO substrate through spray-pyrolysis technique. The sizes of the thin-film are estimated through field-emission scanning electron microscopy(FESEM) images,exhibited that the films are mono-dispersed, and nearly spherical with the average size lies in the range of 50nm to 100nm, which increases...

New electrode materials for supercapacitor devices are the primary focus of current research into energy-storage devices. Besides, exact control of the proportions of these new materials while forming electrodes for coin cell supercapacitor devices is very important for the large-scale manufacturing or at industrial scale. Here we report a facile s...

Nanofluids have become of interest in recent years thanks to their improved thermal properties, which make them especially interesting for microchannel heat sink applications. In this study, we prepared two aqueous nanofluids based on reduced graphene oxide (rGO) decorated with manganese dioxide (MnO2) at a concentration of 0.1 wt.%. The difference...

Metal-organic frameworks (MOFs) have emerged as promising tailor-designed materials for developing next-generation solid-state devices with applications in linear and nonlinear coherent optics. However, the implementation of functional devices is challenged by the notoriously difficult process of growing large MOF single crystals of high optical qu...

In the present work, halloysite nanotubes modified with gold nanoparticles (AuNPs-HNT) are successfully prepared by wet chemical method for the catalytic degradation of phenothiazine dyes (azure B (AZB) and toluidine blue O (TBO)) and also cleaner reduction of 4-(4-nitrophenyl)morpholine (4NM) in the sodium borohydride (NaBH4) media. The catalyst i...

In this study, novel 3D/3D/2D-Co3O4/Bi2O3/rGO ternary nanocomposites is were successfully synthesized via hydrothermal technique assisted with self-assembly process. The prepared materials were characterized for their morphological, structural, and optical properties using various techniques such as XRD, FTIR, SEM, EDX, TEM, and UV-DRS. The composi...

Inclination to exploit renewable energy and their potential storage by facile, cost-effective, and above all in a green way are exactly what the current alternative energy research is looking for. The high-performance supercapacitor devices made up with the electrode materials synthesized in a simple and ecofriendly way are in utmost demand and the...

This work focuses on the preparation and structural characterization of the semiconductor Cu3In5Se9, an important member of ordered vacancy compounds family, belonging to the semiconductor system I3-III5--VI9, where denotes the cation vacancy which is included in the formula to maintain the same number of cations and anions sites. This material was...

The solvothermal synthesis of metal–organic frameworks (MOFs) often proceeds through competing crystallization pathways, and only partial control over the crystal nucleation and growth rates is possible. It challenges the use of MOFs as functional devices in free-space optics, where bulk single crystals of millimeter dimensions and high optical qua...

div> Metal-organic frameworks (MOF) have emerged as promising tailor-design materials for developing next-generation solid-state devices with applications in linear and non-linear coherent optics. However, the implementation of functional devices is challenged by the notoriously difficult process of growing large MOF single-crystals of high optica...

div> Metal-organic frameworks (MOF) have emerged as promising tailor-design materials for developing next-generation solid-state devices with applications in linear and non-linear coherent optics. However, the implementation of functional devices is challenged by the notoriously difficult process of growing large MOF single-crystals of high optica...

Water-based nanofluids prepared with ZnO nanoparticles (⩽17 nm) were characterized. The thermal conductivity and viscosity were measured as a function of temperature (278-303 K), for two ZnO concentration (1wt% and 3wt%) establishing that, whereas the nanofluid prepared with a concentration of 1wt% registered an average improvement of the thermal c...

The controllable growth of non-centrosymmetric metal organic framework (MOF) beyond the conventional micrometer crystal dimensions would represent an enabling step in the development of MOF-based devices for coherent nonlinear optics. This goal has been elusive so far, as MOF crystal typical self-assemble under metastable synthesis conditions that...

The graphitic carbon nitride (g-C3N4) material has a unique electronic structure, semiconducting properties, chemical, and thermal stability. These properties make it a suitable candidate for photocatalytic applications. The facile and large scale synthesis of g-C3N4 having new microstructures is always a challenge for its commercial application. A...

Here we report the acetonitrile mediated large scale synthesis of self-assembled bulk cylinder (length ∼ 9.00 cm, diameter ∼ 4.0 cm) consolidated with very long and thin β-AgVO3 nanowires and its enhanced antibacterial activity against bacteria that cause skin/respiratory infections and food poisoning etc. The use of 30 mL acetonitrile during the m...

Recently magnetic nanoparticles (MNPs) have attracted significant attention for various applications in the analytical chemistry. In this regard this chapter first gives a brief overview of the use of these kinds of nanomaterials in the relevant research areas and subsequently the readers can find the different methodologies to produce MNPs having...

In this work, n type Cu5In9Se16 was prepared using the vertical Bridgman–Stockbarger technique. N type conductivity is confirmed by the Hall effect method and also by the standard test Method for conductivity type of extrinsic semiconducting materials. Our samples are crystallized in a tetragonal phase with a P4mm space group. The optical absorptio...

Energy crisis due to the limited source of fossil fuels, increasing demand of energy day by day and above all global warming issue have compelled human being to think about the renewable and sustainable energies. Researchers are intended to develop, efficient energy conversion devices based on the solar energy, wind energy, geothermal energy etc. T...

Astounding graphitic carbon nitride (g-C3N4) nanostructures have attracted huge attention due to its unique electronic structures, suitable band gap, thermal and chemical stability insinuating as a promising candidate for photocatalytic and energy harvesting applications. Growth of a free standing film is desirable for widespread electronic devices...

The optical absorption coefficient α and electrical conduction as a function of temperature of the semiconductor Cu3In5Se9, an ordered defect compound which crystallizes in a tetragonal structure with space group P\( \bar{4} \)2c, have been studied. The band gap energy EG varies between 0.994 eV and 0.983 eV in the temperature range between 25 and...

We describe the structure and properties of [Zn(C6H4N5)N3 ] n , a new nonporous three-dimensional high-energy metal−organic framework (HE-MOF) with enhanced thermal stability. The compound is synthesized by the hydro-thermal method with in situ ligand formation under controlled pH and characterized using single-crystal X-ray diffraction, elemental...

We describe the structure and properties of [Zn(C6H4N5)N3]n , a new nonporous three-dimensional high-energy metal−organic framework (HE-MOF) with enhanced thermal stability. The compound is synthesized by the hydro-thermal method with in situ ligand formation under controlled pH and characterized using single-crystal X-ray diffraction, elemental an...

The significance of graphene and its two dimensional (2D) analogous inorganic layered materials especially as h-BN and MoS2 for “clean energy” applications became apparent over the last few years due to their extraordinary properties. In this review article we study the current progress and selected challenges in the syntheses of graphene, h-BN and...

A perfect two dimensional material called as graphene, its oxides and derivatives due to its astounding, electrical, thermal, mechanical, optical properties have a great white hope for various applications in the area of materials science, including nanoscience and nanotechnology, optics, energy sector and biomedicine. The oxidized form of graphene...

The title compound, [Ni(C10H8N2)3](C9H5N4O)22H2O, crystallizes as a racemic mixture in the monoclinic space group C2/c. In the crystal, the 1,1,3,3-tetracyano-2-ethoxypropenide anions and the water molecules are linked by O—HN hydrogen bonds, forming chains running along the [010] direction. The bpy ligands of the cation are linked to the chain via...

Noncentrosymmetric single-crystal metal-organic frameworks (MOFs) are promising candidates for phase-matched nonlinear optical communication. However, the typical hydrothermal synthesis conditions produce small crystals with relatively low transmittance and poor phase matching. In the search for optimal crystal morphology, we study the effect of th...

Here we report a facile and fast ascorbic acid based controlled growth of various nanostructures of Cu and Cu 2 O by varying the concentration of NaOH. Ascorbic acid being a weak reducing agent not only slows down the reaction kinetics but also provides a better control for the self-assembly of nanostructures. Cu and Cu 2 O nanoparticles are synthe...

Quantum dots (QDs) are small nanometer-sized (< 10 nm) pure or composite materials with excellent novel properties, thus making them interesting and emerging candidates for new and exceptional applications in biomaterials research fields. As emerging members of QDs, carbon (especially, carbon QDs- CQDs & graphene QDs-GQDs) and semiconducting QDs ha...

Non-centrosymmetric single-crystal metal-organic frameworks (MOF) are promising candidates for phase-matched nonlinear optical communication, but typical hydrothermal synthesis produces small crystals with relatively low transmittance and poor phase matching. We study the effect of the metal-to-ligand molar ratio and reaction pH on the hydro-therma...

p>We report the synthesis of Zn(C6H4N5)N3, a new three-dimensional metal-organic framework (MOF) that exhibits strong energetic properties with high thermostability. The compound is synthesized by the hydrothermal method with in situ ligand formation under controlled pH. Structural characterization is carried out by single-crystal XRD, elemental an...

Hexaaquazinc(II) dinitrate 5-(pyridinium-3-yl)tetrazol-1-ide, [Zn(H 2 O) 6 ](NO 3 ) 2 ·2C 6 H 5 N 5 , crystallizes in the space group P \overline{1}. The asymmetric unit contains one zwitterionic 5-(pyridinium-3-yl)tetrazol-1-ide molecule, one NO 3⁻ anion and one half of a [Zn(H 2 O) 6 ] ²⁺ cation (\overline{1} symmetry). The pyridinium and tetrazo...

Graphene, reduced graphene oxide (rGO) and derived materials have emerged as promising solutions for applications in renewable energy storage/conversion devices. No alternatives are known to simultaneously exhibit large specific surface area, high electrical conductivity, good chemical stability, high mechanical strength and flexibility. This revie...

We report the synthesis and structural diversity of Zn(II) metal-organic framework (MOF) with in situ formation of tetrazole ligand 3-ptz [3-ptz = 5-(3-pyridyl)tetrazolate] as a function pH. By varying the initial reaction pH, we obtain high-quality crystals of the noncentrosymmetric three-dimensional MOF Zn(3-ptz)2, mixed phases involving the zinc...

The two-dimensional (2D) derivative of graphite termed graphene has widespread applications in various frontiers areas of nanoscience and nanotechnologies. Graphene in its oxidized form named as graphene oxide (GO) has a mixed structure equipped with various oxygen containing functional groups (epoxy, hydroxyl, carboxylic and carbonyl etc.) provide...

div> We report the synthesis and structural diversity of Zn(II) MOF with in situ formation of tetrazole ligand 3-ptz [3-ptz = 5-(3-pyridyl)tetrazolate], as a function pH. By varying the initial reaction pH, we obtain high-quality crystals of the non-centrosymmetric 3D MOF Zn(3-ptz)2, mixed phases involving the zinc-aqua complex [Zn(H2O)4(3-ptz)2]...

A controlled growth of nano/micro rods with defined morphologies are of great interest due to its special and unique properties. Here we report ethylene glycol mediated facile and controlled synthesis of ultra-long (∼100 μm) perfect hexagon shaped microrods of silver molybdate by a cost effective method of hydrothermal. The exact conditions are opt...

We report the facile, one-step acetonitrile-mediated synthesis and self-assembly of β-AgVO3 nanowires into three-dimensional (3D) porous spongy-like hydrogel (~ 4 cm diameter) as cathode material for lithium ion battery of high performance and long-term stability. 3D structures made with superlong, very thin, and monoclinic β-AgVO3 nanowires exhibi...

We report the synthesis of palladium-graphene oxide based (Pd-rGO) composite and its enhanced electron field emission studies. The palladium nanoparticles decorated reduced graphene oxide (Pd-NPs-rGO) and Pd catalyst assisted grown CNTs on reduced graphene oxide (Pd-CNTs-rGO) composite have been synthesized using microwave method. The hierarchical...

Controlled growth of nano/micro structures by controlling the effective parameters is the basic requirement for the application point of view in various areas. Here we report the facile growth of silver molybdate nano/micro rods by mixing the solution of silver nitrate and ammonium molybdate at ambient condition followed by hydrothermal treatment a...

Microwave heating reaction time dependent various graphene oxide based zinc oxide (G-ZnO) heterostructures such as graphene oxide-ZnO microcubes (GZMC), graphene oxide-ZnO nanoflakes (GZNF) and graphene oxide-ZnO nanoneedles (GZNN) are synthesized by simple and cost effective microwave assisted exfoliation method. These heterostructures supported o...

Till now, several innovative methods have been developed for the synthesis of graphene materials including mechanical exfoliation, epitaxial growth by chemical vapor deposition, chemical reduction of graphite oxide, liquid- phase exfoliation, arc discharge of graphite, in situ electron beam irradiation, epitaxial growth on SiC, thermal fusion, lase...

Till now, several innovative methods have been developed for the synthesis of graphene materials including graphene oxide, reduced graphene oxide through mechanical exfoliation, chemical vapor deposition epitaxial growth, chemical reduction of graphite oxide, liquid- phase exfoliation, arc discharge of graphite, in situ electron beam irradiation, e...

Since the groundbreaking discovery of a new member of the family of carbon nanostructures, namely, "graphene," discovered by A.K. Geim and K.S. Novoselov in 2004, its widespread applications in various areas further accelerated the research activity in the area of synthesis and characterization of graphene by simple, viable, and low-cost techniques...

Carbon nanomaterials have huge potential in the field of energy and environmental applications. However, a wide range of greener and environment friendly synthesis methods utilizing natural, renewable, cheaper waste materials has to be developed. This will lead to the reduction of green house gases, exploitation of toxic materials and helps in the...

3D hierarchical structures are reported based on graphene–nickel encapsulated nitrogen-rich aligned bamboo like carbon nanotubes, which show not only high-performance supercapacitance behavior but also a great robust cyclic stability. A facile synthesis route is developed of 2D nickel oxide decorated functionalized graphene nanosheets (2D-NiO-f:GNS...

3D hierarchical structures are reported based on graphene–nickel encapsulated nitrogen-rich aligned bamboo like carbon nanotubes, which show not only high-performance supercapacitance behavior but also a great robust cyclic stability. A facile synthesis route is developed of 2D nickel oxide decorated functionalized graphene nanosheets (2D-NiO-f:GNS...

Here we report the electrochemical performance of a interesting three dimensional (3D) structures comprised of zero dimensional (0D)- cobalt oxide nanobeads, one dimensional (1D) Carbon nanotubes and two dimensional (2D) graphene, stacked hierarchically. We have synthesized 3D self-assembled hierarchical nanostructure comprised of cobalt oxide nano...

Three kinds of carbon nanostructures, i.e.,graphene nanoflakes (GNFs), multi walled carbon nanotubes (MWCNTs), and spherical carbon nanoparticles (SCNPs) were comparatively investigated in one run experiment. These carbon nanostructures are located at specific location inside the direct current plasma-assisted arc discharge chamber. These carbon nano...

Highly dispersed TiO 2 nanoparticles on graphene nanosheets were achieved by hydrothermal treatment of graphene nanosheets obtained by modified Hummer's method followed by thermal exfoliation. The hybrid graphene TiO 2 nanostructure composite (H-GTN) showed enhanced optical and electrochemical properties for future application as a supercapacitor....

Highly dispersed TiO2 nanoparticles on the graphene nanosheets were achieved by hydrothermal treatment of graphite oxide powder obtained by modified Hummer’s method. Hybrid graphene TiO2 nanostructures composite (H-GTN) showed enhanced optical and electrochemical properties for future application as a supercapacitor. The structural, optical and ele...

In this communication, we have shown that gold nanoparticles (Au (NPs)) embedded in Rubia cordifolia (RC) matrix (RC-Au (NPs)) exhibits high therapeutic value relating to anti-inflammatory characteristic. It was prepared by utilizing the reducing property of RC to convert HAuCl4 into Au (NPs). In order to compare its effectiveness, with respect to...

Mixed metal oxides (MeTMOs) combining a metal and a transition metal oxide have recently become a subject of great interest these days. Metal-vanadtes/tungstates/molybdates etc. are special class of materials that have emerged various interesting physical and chemical properties and many more are yet to be explored. Molybdates are quite interesting...

Synthesis of nanomaterials by a simple, low cost and in high yield has been a great challenge since the very early development of nanoscience. Various bottom and top down approaches have been developed so far, for the commercial production of nanomaterials. Among all top down approaches, high energy ball milling, has been widely exploited for the s...

Silver molybdate microrods are self-assembled into micron sized, broom-like and flower-like structures. Our investigations indicate that through a simple hydrothermal process, large scale production of such structure is possible. Using ammonium molybdate and silver nitrate solutions as precursors, we were able to show that the self assembled archit...

Nanothread, nanotetrapod and nanocube like structures of SnO 2 have been synthesized by anodic oxidation through a simple electrolysis process utilizing tin as a sacrificial electrode. The synthesized nanostructures were dependent to applied potential between the electrodes. The method is based on anodization pursuant to the simple electrolysis of...

Micron sized hexagon-and flower-like nanostructures of lead oxide (α-PbO2) have been synthe-sized by very simple and cost effective route of anodic oxidation of lead sheet. These structures were easily obtained by the simple variation of applied voltage from 2-6 V between the electrodes. Lead sheet was used as an anode and platinum sheet served as...