Vinod Kumar

Vinod Kumar
DaDU

PhD

About

130
Publications
46,620
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4,267
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Introduction
I am working as Inspire Faculty at CES, Indian Institute of Technology Delhi, New Delhi from Dec 2015. I have experienced to work as a Visiting Scientist/Post-doc Researcher at UCA France; TU US; UFS South Africa and IUAC India. I was worked as a Junior Research Fellow from 2008-2009 at University of Delhi, India. My research work is focused on third generation solar cell and LED.
Additional affiliations
March 2018 - present
UCA, France
Position
  • PostDoc Position
December 2015 - present
Indian Institute of Technology Delhi
Position
  • Inspire Faculty
October 2012 - December 2015
University of the Free State
Position
  • PostDoc Position

Publications

Publications (130)
Book
This book provides an overview of the applications of ion beam techniques in oxide materials. Oxide materials exhibit defect-induced physical properties relevant to applications in sensing, optoelectronics and spintronics. Defects in these oxide materials also lead to magnetism in non-magnetic materials or to a change of magnetic ordering in magnet...
Article
The electric field-assisted spray deposition of highly conducting and transparent gallium doped zinc oxide (GZO) films, with noticeable improvement in optical, structural, and electrical properties, is reported for application in organic photovoltaics with superior device performance. The GZO films deposited with applied voltages of 0 and 2000V to...
Chapter
Polymers have been reported widely in the last few decades by the scientific community due to their versatile and adjustable chemical properties. The word “polymer” comes from the Greek words “poly,” meaning many, and “meros,” meaning parts. Therefore, the meaning of “polymer” is “many parts.” Most of the large molecules or macromolecules are polym...
Article
Upconversion (UC) emission of Er–Yb doped strontium tungstate (SrWO4:Er³⁺-Yb³⁺) thin films on silicon substrates prepared by the radio frequency (RF) magnetron sputtering method using different RF powers has been investigated and reported. The X-ray diffraction patterns showed that the tetragonal phase of SrWO4 formed with an improvement in the cry...
Article
nanocomposite thin films on glass substrate are optimized and then used for fabrication of Si based solar cells. This is an in-situ attempt towards the fabrication of the photovoltaic cells by using the composition CdO:TiO 2 on p-Si. Simultaneously, enhanced the conductivity and reduced toxicity of CdO by using TiO 2. The interfacial layer of CdO:T...
Conference Paper
Spray deposited poly (3,4 ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) is used as a hole transport layer (HTL) at different thickness. These HTL layer is characterized in terms of structural and electrical properties. The thickness of HTL layer is varied from 40 to 120 nm by altering deposition time from 20 to 60 sec. The lowest t...
Article
Thin films of the ternary polymer blend (donors PCE-10 and PCDTBT with the acceptor PC71BM in chlorobenzene) were fabricated by using spray coating technique without and with applied voltage to the nozzle during deposition. The increased absorption range from 400 nm to 800 nm indicates that Förster resonance energy transfer (FRET) is occurring for...
Article
Differently coloured TiO2 nanoparticles was fabricated by continuous spray pyrolysis (CoSP) technique due to the controlled manner of defect formation in large scale synthesis of black, green and white TiO2 with creation of selective Ti³⁺ defects as well as defects correlated to oxygen vacancies. The enhancement in the zone temperatures in CoSP fur...
Article
The present work describes the synthesis of pure and Zn doped CdO (CdO:Zn) nanorods synthesized by a simple low-cost combustion technique. The optical, structural, morphological, and surface properties, as well as antimicrobial activities of the CdO:Zn nanoparticles were studied with respect to pure CdO. UV − Vis spectrometry and photoluminescence...
Article
K2SiF6 and BaSiF6 nanoparticles are synthesized for the first time by thermal decomposition of a mixture consisting of oleic acid and 1-octadecene using ammonium fluoride as fluorine source instead of highly toxic hydrofluoric acid. The structural and morphological properties of the as-obtained nanocrystals are investigated.
Article
Highly conducting and transparent undoped and indium doped tin oxide (SnO2:In) thin films are prepared by spray technique at different doping concentration of Indium (In). The X-ray diffraction pattern of SnO2:In thin films are confirmed the tetragonal phase of SnO2. The resistivity of SnO2:In film is increased with increased the doping concentrati...
Article
Full-text available
CdO : ZnO hexagonal particles were synthesized by a sol–gel precipitation method at different annealing temperatures. A mixed crystal phase of cubic and wurtzite structures was observed from X-ray diffraction patterns. The micrographs showed hexagonal shapes of the CdO : ZnO nanocomposites particles. The energy dispersive X-ray spectroscopy mapping...
Article
Organic-inorganic hybrid solution composing of Continuous Spray Pyrolyzed (CoSP) synthesized molybdenum trioxide (MoO3) nanorods in poly(3,4-ethylene dioxy thiophene): poly(styrenesulfonate) (PEDOT:PSS) were developed to form an effective interconnecting layer for use as a hybrid hole transport layer (HTL) in organic solar cells (OSCs). Compared to...
Article
Eu³⁺ doped ZnO (ZnO:Eu³⁺) thin films were prepared by pulsed laser deposition at different oxygen partial pressures. The all ZnO:Eu³⁺ thin films have a hexagonal structure. The morphology and roughness of the ZnO:Eu³⁺ thin film were also dependent on the partial pressure of the oxygen. The strong band to band emission was observed with the weak emi...
Chapter
Rare earth doped/codoped upconversion nanoparticles facilitate anti-Stokes emission with different pump power and also show nonlinear optical properties with infrared excitation. The interesting properties such as anti-Stokes shifts, long lifetimes and sharp emissions have attracted researchers’ attention in diverse field applications. Here, in thi...
Conference Paper
Methylamionium iodo bismuthate (MBI) perovskite is a promising alternative of hybrid organic-inorganic lead perovskite devices because of its better stability and low toxicity compared to lead based perovskite. Spray deposition technique was used to deposit lead free Bismuth Iodide Perovskite thin film with different thickness. The crystal structur...
Article
Full-text available
ZnO-TiO2:0.4 mol. %Dy³⁺,x mol. %Eu³⁺ (x = 0.05, 0.15, 0.25, 0.50, and 0.75) nanophosphors were synthesized using the solgel method. X-ray diffraction data confirmed crystallization of a mixture of wurtzite hexagonal ZnO and tetragonal TiO2 (anatase and rutile) nanocomposite phases. The nanocomposites were excited in the ultraviolet region with a wa...
Article
Full-text available
Solution-processed Methylammonium iodo bismuthate (MBI) perovskite solar cell is fabricated by spray technique with changed applied voltages from 0 to 1000 V during the deposition of MBI thin film. The morphology and surface roughness of MBI films are influenced significantly by the electric field during film deposition. It is attributed to improve...
Article
Poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) doped with Eu³⁺ is spray deposited for creating an Anode buffer layer (ABL). The doping of Eu³⁺ in PEDOT:PSS causes the down-shifting of the UV light to visible spectrum enhancing the photon concentration in this region. The use of electric field during the spray deposition of un...
Article
Zinc oxide (ZnO) nanoparticles were prepared by a green process using a simple sonochemical method. The prepared nanoparticles were annealed at different annealing temperatures in order to determine the role of the annealing temperature on the structural, morphological and optical properties of the prepared material. The defects related photolumine...
Article
Rare earth doped/codoped phosphors have been extensively studied for different types of applications based on their intense luminescence features. For this, researchers have tried to choose the inorganic host matrices having both a low phonon cut-off frequency and a high refractive index. Many articles have been published on oxide based phosphor ma...
Article
xZnO:(1-x)TiO2 (x = 1.0, 0.6, 0.5, 0.4, 0.0) nanocomposites powder were synthesized by sol-gel method. The X-ray diffraction results have shown a mixed phase of titanium dioxide and zinc oxide. The average crystallite size was found in the range of 20–45 nm. The absorbance of ZnO:TiO2 nanocomposite powder was measured in the wavelength range from 3...
Article
Erbium (Er³⁺) and ytterbium (Yb³⁺) co-doped ZnO upconversion (UC) nanoparticles based phosphors are synthesized by solution-combustion method. These UC phosphors are shown a strong UC emissions at red, green and blue wavelengths with the excitation of 980 nm diode laser source. To understand the influence of ZnO:Er³⁺-Yb³⁺ UC based nanoparticles on...
Chapter
The growing demand for energy-efficient materials needs advancement in existing approaches. Photon upconversion is an effective way to overcome this issue. Novel upconverting materials show their potential in the advancement of energy conservation and lighting technology. In this contest, lanthanide-activated inorganic luminescent materials play a...
Article
Y2O3:Bi³⁺ thin films of various microstructures were deposited using different deposition times by means of a radio frequency magnetron sputtering system. The deposition time affects the surface morphology, crystalline phase and the optical properties of the Y2O3:Bi³⁺ thin films. The films with the shorter and longer deposition time were amorphous...
Conference Paper
Full-text available
ZnO and CdO:ZnO nanoparticles are synthesized by sol-gel precipitation method. The structural analysis shows composite structure for CdO:ZnO nanoparticles with (002) and (111) phase. The SEM images show wedge like morphology and 3-D hexagonal morphology with ∼110 nm in size. The uniform growth of CdO:ZnO nanoparticles were observed in EDS element m...
Article
Full-text available
ZnO:Eu³⁺/Er³⁺/Yb³⁺thin films were deposited on Si (100) substrates using the sol–gel spin coating technique. The effect of Yb³⁺ concentration on the structure, particle morphology and optical properties of the films was examined. X-ray diffraction data showed that all the thin films crystallized in a hexagonal wurtzite structure of ZnO. The particl...
Article
Producing novel functional nanomaterials with high reproducibility is extremely desirable but very challenging. Further treatment by reliably combining or embedding nanoparticles into a protecting medium could be a promising approach to retain their properties and realize practical applications. In this work, we report the preparation, characteriza...
Article
A comprehensive review of up-conversion (UP) and down-conversion (DC) or down shifting of rare earth (RE) doped zinc oxide (ZnO) nanophosphors is presented. Research interest in the development of RE³⁺ doped ZnO for UP and DC nanophosphors has been encouraged by the potential application of these materials in light emitting diodes and different typ...
Article
This article reports on the frequency upconversion property of yellow light emitting Ho³⁺-Yb³⁺ embedded tungsten tellurite (TeO2-WO3) glass prepared by the famous melt-quench technique. Holmium activated TeO2-WO3 glass gives efficient visible and near-infrared upconversion luminescence upon 980 nm excitation, which improved via the incorporation of...
Article
Er³⁺/Tm³⁺ doped and codoped Na2O-SiO2-ZnO (NSZO) glasses were prepared by the conventional melt-quenching method. The amorphous nature of the prepared glasses was confirmed by the X-ray diffraction analysis. The optical absorption spectrum displayed several peaks, which correspond to Er³⁺ and Tm³⁺ dopant ions embedded into the NSZO glass. Both dopa...
Article
Cadmium oxide (CdO) thin films have been deposited onto glass substrates using different molar concentrations (0.2 M, 0.5 M and 0.8 M) of cadmium acetate precursor solutions using a sol-gel spin coating technique. The structural, morphological, optical and electrical results are presented. X-ray diffraction patterns indicated that the CdO films of...
Article
We report on the sol-gel based room temperature synthesis of undoped SnO2 and Ag-SnO2 nanostructures. The synthesized nanostructures were characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, High-resolution transmission electron microscopy (HR-TEM) and UV-visible spectroscopy. The XRD pattern confir...
Article
This study reports on the photoluminescence and cathodoluminescence behaviour of combustion synthesized CaMoO4:Ho³⁺ phosphor. X-ray diffraction and scanning electron microscopy revealed the formation of single phase tetragonal structure consisting of well-prepared evenly distributed micro-sized grains. Power tunable visible upconversion and infrare...
Article
Dysprosium (Dy 3þ) activated ZnO-TiO 2 nanocomposite phosphors were successfully synthesized by the sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR), UVeVis spectroscopy, X-ray photoelectron spec-troscopy and photo-luminescent (PL) spectroscopy...
Article
The structure, particle morphology and luminescent properties of europium (Eu 3+) doped ZnO nanoparticles (NPs) prepared by co-precipitation method are discussed. When excited using a 325 nm He-Cd laser, undoped ZnO NPs exhibited weakly the well-known ultraviolet excitonic recombination emission (at ~ 384 nm) and strongly broad band visible emissio...
Article
The effect of sol concentration has been investigated on the sol-gel derived CdO nanostructures to optimize the optical and electrical properties enhancing gas sensing properties at low temperatures. X-ray diffraction patterns show that 0.5 M CdO film has cubic structure (111) preferred orientation with 34 nm particle size. Scanning electron microg...
Article
Rare earth Eu³⁺/Dy³⁺ ions doped/co-doped Na2O-SiO2-ZnO (NSZO) glasses were prepared by the conventional melt-quenching method. The amorphous nature of the prepared glasses was confirmed by the X-ray diffraction analysis and scanning electron microscopy whereas elemental compositions and mappings had been obtained from energy dispersive spectroscopi...
Article
The sol gel method was used to prepare rare-earths (Yb³⁺-Er³⁺ and Yb³⁺-Tm³⁺) co-doped Al2O3-TiO2 nano-composite powder phosphors and their up-conversion luminescence properties were investigated. Mixed oxides of titania (TiO2) rutile phase and an early stage crystallization of alumina (Al2O3) phase were confirmed from the X-ray diffraction data wit...
Article
Y2O3:Bi³⁺ thin films have been fabricated onto Si substrates by the radio frequency magnetron sputtering technique. The influence of different annealing temperature was studied by X-ray diffraction(XRD), Atomic force microscopy, scanning electron microscopy and Photoluminescence (PL). The XRD study revealed that, the Y2O3:Bi³⁺ thin films have a cub...
Article
In today’s times where pollution of all kinds is at its peak, numerous efforts are being made to find proper waste disposal methods. Moving on the same lines, this paper presents an economical and environmentally safe method of disposal of red mud to control electromagnetic pollution by using it as an electromagnetic shielding material. Composites...
Article
Mixed oxides of zinc and cadmium with different proportions were deposited on ordinary glass substrates using the sol-gel spin coating method under optimized deposition conditions using zinc acetate dihydrate and cadmium acetate dihydrate as precursors. X-ray diffraction patterns confirmed the polycrystalline nature of the films. A combination of c...
Article
Ytterbium (Yb³⁺) doped aluminium oxide (Al2O3) powder phosphor was successfully synthesized by solution combustion method. The structure, vibrational bending modes, particle morphology, chemical composition, and photoluminescent properties were analysed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron...
Article
The effect of different annealing temperatures on the photoluminescent properties of bismuth doped yttrium oxide (Y2-xO3:Bix)phosphor powders was investigated with various optical spectroscopy instruments for a possible down-conversion candidate for solar cells. Results showed that the emission intensity increased by increasing the annealing temper...
Article
Metal oxide semiconductors are promising materials for fabricating p-n heterojunctions which are technologically important for many electronic devices. The reason is their unique characteristics of tuneable electrical properties that can be controlled by doping. In the present work, a p-n heterojunction was fabricated by depositing nitrogen doped z...
Article
The reactive radio-frequency (RF) magnetron sputtering and spin coating fabrication techniques were used to fabricate Y2-xO3:Bix=0.5% phosphor thin films. The two techniques were analysed and compared as part of investigations being done on the application of down-conversion materials for a Si solar cell. The morphology, structural and optical prop...
Article
Terbium (Tb3+) doped zinc oxide (ZnO) or (ZnO:Tb3+) thin films were grown on silicon substrates by the pulsed laser deposition technique at different growth temperatures that were varied from room temperature (RT) to 400°C. The effects of substrate temperature on the structural and optical properties of the ZnO:Tb3+ films were investigated by X-ray...
Article
Full-text available
SrGa2S4:Ce3+ thin films coated with a very thin layer of TaSi2 were deposited on Si(100) substrates utilizing the pulsed laser deposition system. During the ablation of the targets for thin films preparation, the Si(100) substrate temperature varied in the range of 400–600 °C. The as-deposited SrGa2S4:Ce3+ films showed an orthorhombic crystal struc...
Article
Au nanoparticles (NPs) on the surface and embedded in a matrix have been the subject of studies dealing with a variety of spectroscopic and sensing applications. Here, we report on low energy Ar ion induced evolution of the morphology of a thin Au film on a polyethylene terephthalate (PET) substrate along with thermodynamic interpretations, and cor...
Article
This paper reports on the comparative investigation of the spectroscopic properties of the Y3Al5O12 (YAG) and Y3Ga5O12 (YGG) doped with Eu3+ synthesized by the combustion method. A pure phase was identified for the YGG phosphor, but one other phase was observed for the as-prepared and annealed YAG phosphor. A high intense red color emission was obs...
Article
Nitrogen doped ZnO (NZO) thin films were synthesized on glass substrates by sol-gel and spin coating method. Zinc acetate dihydrates and ammonium acetate were used as precursors for zinc and nitrogen, respectively. X-ray diffraction study showed that the thin films have a hexagonal wurtzite structure corresponding (002) peak for undoped and doped Z...
Article
Full-text available
Tin oxide (SnO2) nanocrystals (NCs) based phosphor was synthesized by a green chemistry microwave-assisted hydrothermal method at different reactor pressures. The x-ray diffraction analysis showed that a single rutile SnO2 phase with a tetragonal lattice structure was formed. The photoluminescence emission was measured for He–Cd laser excitation at...
Article
In this study, europium doped yttrium gadolinium (Y1.4Gd0.5Eu0.1O3) mixed oxide phosphors were synthesized by a sonochemical method at different growth temperatures (50 oC, 100 oC, 150 oC and 200 oC) for pure red light emission applications. The compositional identification, presence of dopants and the distribution of doping materials in the crysta...
Article
N-doped and Al-N codoped ZnO thin films with different volume ratios of N2 reactive gas were deposited on plane glass substrates using the radio frequency magnetron sputtering method. The phase transition temperature and absorption edge of the ZnO powder were studied by differential scanning calorimetry at different heating rates and with Fourier t...
Article
Full-text available
The preparation of a variety of b-ketoesters was achieved in high yields from methyl acetoacetate under neutral conditions through the utilization of magnetic CuFe2O4 nanoparticles as catalyst. Recycling of the catalyst was performed up to eight times without significant loss in activity. The catalyst was characterized using XRD, XPS, SEM and TEM t...
Article
Full-text available
The objective of the present investigation was to develop colon-specific drug delivery systems for amoxicillin trihydrate and paracetamol using Gum ghatti (Gg) based cross-linked hydrogels. An interpenetrating network (IPN) of electrically active hydrogel based on Gg, poly(acrylic acid) (AA) and polyaniline was synthesized by a two-step aqueous pol...