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1.
Chemosphere ; 359: 142369, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38761825

RESUMEN

The present article portrayed on the killing kinetic of human pathogenic bacteria using bioinspired mesoporous CuAl2O4 nanocomposites (NCs). The NCs was fabricated using leaf extract of medicinal plant Catharanthus roseus (CR) as a green reducer and stabilizer. As bio-fabricated material was calcined at 800 °C and characterized by several analytical techniques like X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS), Energy Dispersive X-Ray Spectroscopy (EDS), X-Ray Photoelectron Spectroscopy (XPS), Raman, Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) to authenticate its structure, phase, chemical bonding, chemical state, size and morphology behaviors. XRD and TEM revealed a reduced crystallite and nanoscale sizes of biosynthesized NCs. Moreover, XRD study exposed a cubic-structure of material, while transmission electron microscopy rendered an average particles size in range 10-15 nm. However, BET profile advocates a mesoporous nature of the particles. An effective biological molecular docking modulation assessed by substituting natural inhibitor by bioinspired NCs, while the protein PDB ID 4Z8D FabH as a receptor site for the present investigation. After assessment of molecular docking examination, the antibacterial activity of bioinspired NCs were performed against Staphylococcus aureus, Bacillus subtillis, Klebsiella pneumoniae and Escherichia coli using agar-well method. The broth culture method was employed on different pathogenic strains by kinetic growth assays and colony forming unit.


Asunto(s)
Catharanthus , Nanocompuestos , Extractos Vegetales , Catharanthus/química , Nanocompuestos/química , Cinética , Extractos Vegetales/química , Extractos Vegetales/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Simulación del Acoplamiento Molecular , Escherichia coli/efectos de los fármacos , Difracción de Rayos X , Hojas de la Planta/química , Espectroscopía Infrarroja por Transformada de Fourier , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos
2.
Chem Asian J ; : e202300813, 2023 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-37939281

RESUMEN

A variety of unique compounds have been examined to accommodate the current demand for useful multi-functional nanomaterials, copper-based quaternary CZTS semiconductors are one of them. Due to their special characteristic features like non-toxicity, cheap, and abundance, they have been recommended in recent literature for various applications. Apart from individual CZTS, different hetero-structures have also been prepared with different compounds which is well discussed and elaborated in this article. Additionally, their preparation methods, properties, and application viability have also been discussed comprehensively. The application of CZTS such as photocatalytic dye degradation and hydrogen evolution reaction has been elaborated on in this article identifying their benefits and challenges to give readers a thorough visualization. Apart from that, challenges reported in studies, a few approaches are also mentioned to possibly counter them.

3.
J Am Chem Soc ; 145(37): 20451-20461, 2023 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-37694929

RESUMEN

Integrating an NIR fluorescent probe with a magnetic resonance imaging (MRI) agent to harvest complementary imaging information is challenging. Here, we have designed water-soluble, biocompatible, noncytotoxic, bright-NIR-emitting, sugar-functionalized, mechanically interlocked molecules (MIMs)-capped superparamagnetic ultrasmall Fe3O4 NPs for targeted multimodal imaging. Dual-functional stoppers containing an unsymmetrical NIR squaraine dye interlocked within a macrocycle to construct multifunctional MIMs are developed with enhanced NIR fluorescence efficiency and durability. One of the stoppers of the axle is composed of a lipophilic cationic TPP+ functionality to target mitochondria, and the other stopper comprises a dopamine-containing catechol group to anchor at the surface of the synthesized Fe3O4 NPs. Fe3O4 NPs surface-coated with targeted NIR rotaxanes help to deliver ultrasmall magnetic NPs specifically inside the mitochondria. Two carbohydrate moieties are conjugated with the macrocycle of the rotaxane via click chemistry to improve the water solubility of MitoSQRot-(Carb-OH)2-DOPA-Fe3O4 NPs. Water-soluble, rotaxane-capped Fe3O4 NPs are used for live-cell mitochondria-targeted NIR fluorescence confocal imaging, 3D and multicolor imaging in combination with T2-weighted MRI on a 9.4 T MR scanner with a high relaxation rate (r2) of 180.7 mM-1 s-1. Biocompatible, noncytotoxic, ultrabright NIR rotaxane-capped superparamagnetic ultrasmall monodisperse Fe3O4 NPs could be a promising agent for targeted multimodal imaging applications.


Asunto(s)
Nanopartículas , Rotaxanos , Imagen por Resonancia Magnética , Imagen Óptica , Nanopartículas Magnéticas de Óxido de Hierro
4.
RSC Adv ; 13(4): 2561-2569, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36741164

RESUMEN

A unique strategy for the synthesis of a supramolecular metallogel employing zinc ions and adipic acid in DMF medium has been established at room temperature. Rheological analysis was used to investigate the mechanical characteristics of the supramolecular Zn(ii)-metallogel. Field emission scanning electron microscopy and transmission electron microscopy were used to analyse the hexagonal shape morphological features of the Zn(ii)-metallogel. Interestingly, the electrical conductivity is observed in the electronic device with Zn(ii)-metallogel based metal-semiconductor (MS) junctions. All aspects of the metallogel's electrical properties were investigated. The electrical conductivity of the metallogel-based thin film device was 7.38 × 10-5 S m-1. The synthesised Zn(ii)-metallogel based device was investigated for its semi-conductive properties, such as its Schottky barrier diode nature.

5.
Environ Res ; 222: 115363, 2023 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-36716808

RESUMEN

The present article reports the synthesis of thoria nanoparticles (ThO2 NPs) via sol-gel process and examines the effect of calcination temperature of ThO2 on the morphology and photocatalytic degradation of indigo carmine (IC) and methylene blue (MB) under visible-light. As-synthesized white crystals of ThO2 were subjected to calcination at different temperatures, viz. 700 °C (TH-700), 800 °C (TH-800), and 900 °C (TH-900). The effect of calcination temperature on the structural, morphological, thermal, surface area-porosity, and optical properties of ThO2 NPs were investigated by diverse analytical techniques. XRD patterns show the cubic-space group Fm-3m (225) with parameter a = 5.597 Å and reveals crystallite sizes increased with calcination temperature. The bandgap energy was found to be 1.85 eV, 2.33 eV, and 2.71 eV for TH-700, TH-800, and TH-900 NPs, respectively, calculated by Kubelka-Munk (KM) plot. SEM and TEM unveil that the sample TH-700 calcined at a low temperature of 700 °C yields assembled nanosheets, while at higher temperatures, i.e., 800 °C (TH-800) and 900 °C (TH-900), produces agglomerated nanomaterials. Further, TH-700 sample exhibits enhanced photocatalytic degradation within 120 min for both IC and MB dye than TH-800 and TH-900 counterparts. Among the dyes, IC shows improved photocatalytic efficiency than MB for TH-700, owing to the increased optical absorption and improved separation of photogenerated charge carriers. The reusability study of TH-700 reveals that the catalysts were stable up to four successive cycles with no drastic changes in photocatalytic efficiency. Also, systematic photodisintegration of IC was investigated by Liquid chromatography-mass spectrometry (LC-MS).


Asunto(s)
Carmin de Índigo , Nanopartículas , Azul de Metileno/química , Luz , Nanopartículas/química , Colorantes
6.
ACS Omega ; 7(24): 20983-20993, 2022 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-35755359

RESUMEN

Bioinspired delta-bismuth oxide nanoparticles (δ-Bi2O3 NPs) have been synthesized using a greener reducing agent and surfactant via co-precipitation method. The originality of this work is the use of Crinum viviparum flower extract for the first time for the fabrication of NPs, which were further calcined at 800 °C to obtain δ-Bi2O3 NPs. Physicochemical studies such as FTIR spectroscopy and XPS confirmed the formation of Bi2O3 NPs, whereas XRD and Raman verified the formation of the cubic delta (δ) phase of Bi2O3 NPs. However, HRTEM revealed the spherical shape with diameter 10-20 nm, while BET studies expose mesoporous nature with a surface area of 71 m2/gm. The band gap for δ-Bi2O3 NPs was estimated to be 3.45 eV, which ensured δ-Bi2O3 to be a promising photocatalyst under visible-light irradiation. Therefore, based on the results of physicochemical studies, the bioinspired δ-Bi2O3 NPs were explored as active photocatalysts for the degradation of toxic dyes, viz., Thymol blue (TB) and Congo red (CR) under visible-light irradiation. The study showed 98.26% degradation of TB in 40 min and 69.67% degradation of CR in 80 min by δ-Bi2O3 NPs. The photogenerated holes and electrons were found responsible for this enhancement. Furthermore, molecular docking investigations were also performed for δ-Bi2O3 NPs to understand its biological function as New Delhi metallo-ß-lactamase 1 (NDM-1) [PDB ID 5XP9] enzyme inhibitor, and studies revealed good interaction with various amino acid residues and found good hydrogen bonding with a fine pose energy of -3.851 kcal/mole.

7.
Int J Biol Macromol ; 185: 644-653, 2021 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-34217741

RESUMEN

Highly specific graphene-DNA interactions have been at the forefront of graphene-based sensor design for various analytes, including DNA itself. However, in addition to its detection, DNA also needs to be characterized according to its size and concentration in a sample, which is an additional analytical step. Designing a highly sensitive and selective DNA sensing and characterization platform is, thus, of great interest. The present study demonstrates that a bio-derived, naturally fluorescent protein C-phycoerythrin (CPE) - graphene oxide (GO) bio-composite can be used to detect dsDNA in nanomolar quantities efficiently via fluorescent "turn off/on" mechanism. Interaction with GO temporarily quenches CPE fluorescence in a dose-dependent manner. Analytical characterization indicates an indirect charge transfer with a corresponding loss of crystalline GO structure. The fluorescence is regained with the addition of DNA, while other biomolecules do not pose any hinderance in the detection process. The extent of regain is DNA length dependent, and the corresponding calibration curve successfully quantifies the size of an unknown DNA. The incubation time for detection is ~3-5 min. The bio-composite platform also works successfully in a complex biomolecule matrix and cell lysate. However, the presence of serum albumin poses a hinderance in the serum sample. Particle size analysis proves that CPE displacement from GO surface by the incoming DNA is the reason for the 'turn on' response, and that the sensing process is exclusive to dsDNA. This new platform could be an exciting and rapid DNA sensing and characterization tool.


Asunto(s)
ADN/análisis , Grafito/química , Ficoeritrina/química , Proteína C/química , Técnicas Biosensibles , Dispersión Dinámica de Luz , Fluorescencia , Tamaño de la Partícula , Difracción de Rayos X
8.
Curr Pharm Biotechnol ; 22(13): 1782-1793, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33430726

RESUMEN

Nanotechnology is an emerging outlet of nanoscience in which the atoms are encompassed in nanoscale dimensions and become more receptive compared with their distinctive counterparts. Recently, the utilization of synthetic designs and physicochemical approaches has received special attention; nevertheless, the generation of noxious impressions on the eco-system has raised serious concerns of the scientific community worldwide. Presently, environment-friendly green synthesis routes are promising venues for the arrangement of Metal/Metal Oxide (M/MO) nanostructured materials by using plants and their corresponding alliances. This revolution is predominantly recompensing as far as the reduction of toxic emissions and wastes is concerned. Accordingly, material scientists have adopted various renewable naturally-occurring eco-friendly materials, and biogenic processes to fabricate the functional M/MO nanostructured materials. The current review article recapitulates and assimilates the present state of knowledge on different strategies for biogenic fabrication of M/MO nanostructured materials.


Asunto(s)
Nanopartículas del Metal , Nanoestructuras , Nanotecnología , Óxidos , Plantas
9.
Curr Pharm Biotechnol ; 22(13): 1759-1781, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33390112

RESUMEN

Ultra-thin graphene has been receiving significance in the diverse sections of material science, owing to its exceptional physicochemical and thermo-mechanical characteristics. Currently, the fabrication of high-grade graphene in an economical target and green procedures area is a massive concern. Among the diverse techniques, chemical-mediated fabrication is believed to be the finest process since it is simple, scalable, and of low-cost; however, it involves noxious or hazardous chemical reducers for producing functional graphene-based Nanocomposites (NCs). Therefore, around the globe, scientists are endeavoring to adopt the bioinspired techniques to manufacture the functional reduced Graphene Oxide (rGO) and reduced Graphene Oxide-Metal/Metal Oxide (rGO-M/MO) NCs. Hence, keeping this issue in mind, the present review article summarize and integrates the current state of knowledge about the diverse bioinspired strategies developed to obtain rGO and rGO-M/MO NCs and their photocatalytic, antibacterial, and cytotoxic assessments.


Asunto(s)
Antineoplásicos , Grafito , Nanocompuestos , Antibacterianos
10.
Int J Biol Macromol ; 163: 977-984, 2020 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-32629054

RESUMEN

A naturally fluorescent protein, C-phycocyanin (CPC), was used as a fluorophore to study the effect of graphene oxide (GO) as a quencher. The protein was purified using established procedures and titrated with increasing GO concentrations. UV-visible titration showed a minor effect on the phycocyanobilin absorbance but significant interactions with the amino acid backbone. Fluorescence titration showed notable CPC quenching upon increasing GO concentration to 30 µg ml-1; the corresponding fluorescence dropped by ~97%. A non-linear Stern Volmer curve showed that the fluorophores did not interact directly with the quencher. Powder X-ray diffraction studies showed that the bio-composite lost the crystalline arrangement of GO and became amorphous, akin to CPC. SEM analysis showed GO sheets enfolding a protein nucleus with an increase in oxygen after the interaction compared to CPC. A 20 min incubation of the bio-composite with various biomolecules including amino acids, sugars, polydispersed exopolysaccharides (EPS), other proteins and DNA showed that only DNA could recover the CPC fluorescence. The 'turn on' effect of DNA was distinguishable even when all the other molecules were in the same sample matrix. These results showed that CPC GO could be a fluorescence 'turn off/on' DNA probe.


Asunto(s)
Materiales Biocompatibles/química , Técnicas de Química Sintética , Sondas de ADN/síntesis química , Colorantes Fluorescentes/síntesis química , Grafito/química , Ficocianina/química , Sondas de ADN/química , Colorantes Fluorescentes/química , Espectrometría de Fluorescencia , Difracción de Rayos X
11.
ACS Omega ; 5(14): 7823-7835, 2020 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-32309692

RESUMEN

The present article reports a facile approach to fabrication of mesoporous octahedron-shaped tricobalt tetroxide nanoparticles (Co3O4 NPs) with a very narrow size distribution for eco-friendly remediation of toxic dyes. Co3O4 NPs were fabricated by a sol-gel process using cobalt chloride hexahydrate (CoCl2·6H2O) and monosodium succinate (C4H5O4Na) as a chelating/structure-directing agent and sodium dodecyl sulfate as a surfactant. Moreover, the phase structure, elemental composition, and thermal and morphological facets of Co3O4 NPs were investigated using XRD, FT-IR, EDS, Raman, XPS, TGA, SEM, and TEM techniques. The face-centered cubic spinel crystalline structure of the Co3O4 NPs was confirmed by XRD and SEM, and TEM analysis revealed their octahedron morphology with a smooth surface. Moreover, the narrow pore size distribution and the mesoporous nature of the Co3O4 NPs were confirmed by Brunauer-Emmett-Teller measurements. The photocatalytic activity of Co3O4 NPs for degradation of methyl red (MR), Eriochrome Black-T (EBT), bromophenol blue (BPB), and malachite green (MG) was examined under visible light irradiation, and the kinetics of the dye degradation was pseudo-zero-order with the rate constant in the order of MR > EBT > MG > BPB. Furthermore, the mechanism of photo-disintegration mechanism of the dye was examined by a scavenging test using liquid chromatography-mass chromatography, and its excellent photodegradation activities were attributed to the photogenerated holes (h+), superoxide (O2 -) anions, and hydroxyl (·OH) radicals. Finally, the synergistic effect of the nano-interconnected channels with octahedron geometry, mesoporous nature, and charge transfer properties along with photogenerated charge separations leads to an enhanced Co3O4 photocatalytic activity.

12.
Nanoscale Adv ; 2(10): 4473-4481, 2020 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-36132923

RESUMEN

Solar hydrogen generation is one of the most compelling concepts in modern research to address both the energy and environmental issues simultaneously for the survival of the human race. A Type II heterojunction (CoO-GCN) was fabricated by decorating sub 10 nm CoO nanoparticles (NPs) on the graphitic carbon nitride (GCN) surface. It exhibited improved absorption of UV-VIS light and efficiently separate the photogenerated electrons and holes in opposite directions. A maximum hydrogen generation rate of 9.8 mmol g-1 h-1 was recorded using CoO-GCN from 10% aqueous triethanolamine under simulated sunlight in the presence of 1 wt% Pt. The rate is 3.8 times higher than that of bare GCN. Furthermore, it showed excellent stability for up to five repeated uses. Interestingly, the study also revealed that untreated seawater could replace the deionized water. The cooperative participation of the uniform shape and size of CoO NPs firmly grafted on GCN resulted in remarkable performance for solar hydrogen generation.

13.
J Nanosci Nanotechnol ; 20(4): 2344-2350, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-31492246

RESUMEN

SiOx nanodots were fabricated on a TiO2 thin film using glancing angle deposition technique. The fabricated samples were annealed at 950 °C in open air configuration to obtain Si nanoclusters resulting from phase separation of SiOx nanodots. Field Emission Gun Scanning electron microscopy and atomic force microscopy were used to examine the topography of the samples. The elemental composition of the samples was analyzed using energy dispersive X-ray mapping and their crystallinity was confirmed by analyzing the bandgap determined from the Tauc plots. The annealed samples show a broadband absorption which is about two folds in magnitude as compared to the as deposited (unannealed) samples. The photoluminescence spectra confirms the quantum confinement effect in the annealed samples. A photodetector was fabricated from an annealed sample by depositing gold contacts on top of it. This photodetector showed a two-fold increase in dark current and a 1.5-fold increase in light current compared to a photodetector made from the as-deposited SiOx samples-which is due to the increased crystallinity in Si nanoclusters. Finally, the rise and fall times of the device were measured through a switching experiment.

14.
J Nanosci Nanotechnol ; 19(12): 8126-8134, 2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31196335

RESUMEN

Aluminum nanoparticles (AlNPs) were embedded into a sol-gel synthesized In2O3 thin film by using a combination of thermal evaporation and glancing Angle Deposition technique. Presence of different sizes of aluminum nanoparticles was confirmed from field emission gun scanning electron microscopy. The high-resolution X-ray diffraction confirms the formation of Al2O3 NPs by surface oxidation of aluminum nanoparticles. Embedded Metal-Oxide-Semiconductor like device Al/In2O3/AlNPs/In2O3/p-Si was fabricated, and its memristor behavior was analyzed. The Al/In2O3/AlNPs/In2O3/p-Si device possessed high current conduction and analog resistive switching as compared to Al/In2O3/p-Si device. Significant and consistent memory window up to 150 current (I)-voltage (V) loop was obtained for Al/In2O3/AlNPs/In2O3/p-Si device between ±6 V applied bias. The Al/In2O3/AlNPs/In2O3/p-Si device measured high free carrier concentration, i.e., (Nd)~1.93 × 1020 cm-3 calculated from capacitance (C)-Voltage (V) measurement. The memory was retained in accumulation and depletion regions as obtained from the C-V looping curves.

15.
Inorg Chem ; 58(12): 8100-8110, 2019 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-31144809

RESUMEN

We report integrating additional functionality in an amine decorated, robust metal-organic framework (MOF) by encapsulating Ni nanoparticles (NPs). In-depth characterization of the postmodified structure confirms well-dispersed and ultrasmall NPs inside the framework pores. Although, the surface area is more reduced than pristine MOF, the CO2 uptake capacity is remarkably increased by 35% with a large 10 kJ/mol rise in adsorption enthalpy that validates favorable interactions between CO2 and NPs. In particular, CO2 adsorption selectivity over N2 and CH4 displays significant improvement (CO2/N2 = 145.7, CO2/CH4 = 12.65), while multicycle CO2 uptake demonstrates outstanding sorption recurrence. Impressively, the embedded NPs act as highly active functional sites toward solvent-free CO2 cycloaddition with epoxides in 98% yield and 99% selectivity under relatively mild conditions. The catalyst shows high recyclability without leaching of any metal-ion/NPs and greater pre-eminent activity than the unmodified analogue or contemporary reports. Of note is that outstanding conversion and selectivity are maintained for a wide range of aliphatic and aromatic epoxides, while larger substrates exhibit insignificant conversion, demonstrating admirable size selectivity. Based on the literature reports and experimental outcome, a rationalized mechanism is proposed for the reaction. This study exclusively demonstrates how strategic encapsulation of Ni NPs influences the inherent electronic properties in a MOF for highly selective CO2 adsorption and represents a step forward to sustainable CO2 valorization in terms of abundant active sites, sufficient stability, and consistent usability.

16.
Mater Sci Eng C Mater Biol Appl ; 99: 783-793, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30889753

RESUMEN

In the present article we have developed an eco-friendly, phytosynthetic, cost-effective and straightforward method for the synthesis of nearly monodisperse CuO nanospheres (NSP) using leaf extracts of medicinal plants Phyllanthus reticulatus (PR) and Conyza bonariensis (CB) as novel green reducing agents. Copper nitrate (Cu (NO3)2) was used as a precursor. The stoichiometric ratio of both leaf extracts (PR/CB) and Cu(NO3)2 was standardized for the synthesis of NSP. During formation of CuO NSP, a color of solution gradually changed from light greenish-blue to black with a number of intermediate stages and it correlated to the reduction reaction catalyzed by phytochemicals. As-synthesized materials were characterized in detail at the structural, electronic level and morphological authentication by XRD, FT-IR, EDS, UV-DRS, Raman, XPS, SEM, TEM, BET and AFM. SEM studies of phytosynthesized materials revealed nearly monodisperse nanospheres, while TEM rendered average particles size 4-14 nm. Also, AFM profiles suggested a homogenized nature of the nanospheres. Then, the antioxidant property was obtained by α, α-diphenyl-ß-picrylhydrazyl (DPPH). Ethanolic, methanolic extracts were used for the antioxidant activity, while ascorbic acid was used as a standard medium. Each plant extract exhibited noteworthy antioxidant activity. Moreover, the antibacterial activity of CuO NSP (PR/CB) was tested against human pathogenic bacteria viz. gram-positive Staphylococcus aureus, Klebsiella pneumoniae, and gram-negative Escherichia coli. Result rendered effective antibacterial activity against Escherichia coli.


Asunto(s)
Antibacterianos/farmacología , Antioxidantes/farmacología , Conyza/química , Cobre/farmacología , Nanosferas/química , Fotosíntesis , Phyllanthus/química , Bacterias/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Nanosferas/ultraestructura , Extractos Vegetales/farmacología , Espectrometría por Rayos X , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Difracción de Rayos X
17.
J Nanosci Nanotechnol ; 18(7): 4898-4903, 2018 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-29442671

RESUMEN

Indium (In) was doped into TiO2 thin film (TF) using the electron beam evaporation technique followed by an annealing process. The high resolution X-ray diffraction (HRXRD) analysis revealed lower angle diffraction peak (2) shifting of Rutile (002) phases of TiO2 from 61.9 to 61.56 for an increased In doped samples. Calculated average grain size from FESEM (field emission scanning electron microscope) gradually decreased from 21.12 nm to 17.03 mm with an increase in In content ranging from 1.45~17.30 at%. HRXRD data revealed that crystallite sizes also reduced from 21.79 nm to 16.93 nm with an increased In doping concentration. Doping of In leads to the formation of inhomogeneous InxTiy O2 alloy that enhances the transition between 3.3-3.42 eV energy levels with variation in doping concentration. The photo-efficiencies for increased doping concentration of In with 3.47 at% and 17.30 at% were enhanced by 2.56 and 2.76 times, respectively, compared to the undoped TiO2 TF detector and both were larger than low doped In with 1.45 at% sample. The ratio of main band detection intensity to oxygen defect level was also increased from 0.22 to 2.22 with the gradual increase in In content.

18.
J Nanosci Nanotechnol ; 18(7): 5059-5062, 2018 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-29442694

RESUMEN

Glancing Angle Deposition (GLAD) technique was employed to synthesize Ag doped TiO2 nanowire on n-type Si-substrate. FEG-SEM confirms the perpendicular growth of Ag doped TiO2 nanowire with an average height and diameter of ~554 nm and ~40 nm respectively. The composition analysis by EDAX indicates the presence of Ti, O, Si and Ag elements. The increase in PL intensity has been observed with the increase in temperature. Following the growth of Ag doped TiO2 nanowire, Au contacts were deposited to form the Ag doped TiO2 NW based Schottky detector. The enhancement in the photoresponse of the device was observed at -4 V. The device also shows low leakage current of -0.049 µA at -1 V which makes it suitable for enlarged photodetector application.

19.
Chem Asian J ; 13(3): 255-260, 2018 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-29265682

RESUMEN

CdS sheet-rGO nanocomposite as a heterogeneous photocatalyst enables visible-light-induced photocatalytic reduction of aromatic, heteroaromatic, aliphatic and sulfonyl azides to the corresponding amines using hydrazine hydrate as a reductant. The reaction shows excellent conversion and chemoselectivity towards the formation of the amine without self-photoactivated azo compounds. In the adopted strategy, CdS not only accelerates the formation of nitrene through photoactivation of azide but also enhances the decomposition of azide to a certain extent, which entirely suppressed formation of the azo compound. The developed CdS sheet-rGO nanocomposite catalyst is very active, providing excellent results under irradiation with a 40 W simple household CFL lamp.

20.
J Nanosci Nanotechnol ; 15(8): 6098-102, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26369205

RESUMEN

Glancing angle deposition (GLAD) was employed to fabricate the SiOx-In2-xO3-y axial heterostructure nanocolumn. The fabricated heterostructure nanocolumn was annealed at 550 °C for 1 hour at open air condition. The XRD analysis revealed the polycrystalline nature of the annealed SiOx-In2-xO3-y nanocolumn. The emission at 378 nm (~3.3 eV, FWHM 39.101 nm) from Photoluminescence (PL), corresponds to main band gap of In2O3. The In2-xO3-y-SiOx nanocolumn based Schottky detector processed maximum photoresponsivity of 199 A/W at 375 nm, as well as UV-Vis broad band detection. The high internal gain of ~659 at UV region (375 nm) was calculated for the device. The detector exhibited increase in photoresponsivity with decrease in room temperature upto 160 K, which further reduced at low temperature. A very sharp rise time (~1.82 s) and decay time (~1.78 s) was recorded at the applied potential of -2 V and -3 V.

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