scholarly journals Structural and optoelectronic properties of glucose capped Al and Cu doped ZnO nanostructures

2016 ◽  
Vol 34 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Gunjan Patwari ◽  
Pradip Kumar Kalita ◽  
Ranjit Singha
Keyword(s):  
Band Gap ◽  
Average Particle Size ◽  
Blue Shift ◽  
Optoelectronic Properties ◽  
Average Particle ◽  
Zno Nanostructures ◽  
Co Doping ◽  
Ohmic Behavior ◽  
Doped Zno ◽  
Structural And Optoelectronic Properties

AbstractAl and Cu doped ZnO nanoparticles are considered as appropriate for modulation of structural and optoelectronic properties. Al atoms are found to substitute the host Zn whereas Cu dopants mainly segregate in grain boundaries and thereby determine the optical properties. The undoped as well as Al and Cu doped ZnO exhibit spherical well defined particles. The spherical nanoparticles change to rod type structures on co-doping. The average particle size decreases on doping what consequently results in an increment in band gap. Blue shift in UV absorption is governed by the functional group of glucose; further blue shift occurring on metal doping may be attributed to Burstein-Moss effect. PL spectra of doped and undoped ZnO show a dominant near band gap UV emission along with visible emission owing to the defects. The PL peak intensity increases on doping with Cu and Al. The linear I-V characteristics indicate the ohmic behavior of ZnO nanostructures.

scholarly journals Photoluminescences properties of lanthanum-silver co-doped ZnO nano particles

2018 ◽  
Vol 4 (4) ◽  
pp. 135-141 ◽  
Author(s):  
V. Porkalai ◽  
B. Sathya ◽  
D. Benny Anburaj ◽  
G Nedunchezhian ◽  
S. Joshua Gnanamuthu ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Zinc Acetate Dihydrate ◽  
Average Particle Size ◽  
Semiconductor Nanoparticles ◽  
Nano Particles ◽  
Average Particle ◽  
Rare Earth Ion ◽  
X Ray ◽  
Doped Zno ◽  
Co Doped

Recently, transition metal (TM) and rare earth ion doped II–VI semiconductor nanoparticles have received much attention because such doping can modify and improve optical properties of II–VI semiconductor nanoparticles by large amount. In this study, undoped, La doped and La+Ag co-doped ZnO nano particles have been successfully synthesized by sol-gel method using the mixture of Zinc acetate dihydrate and ethanol solution. The powders were calcinated at 600 °C for 2 h. The effect of lanthanum and lanthanum-silver incorporation on the structure, morphology, optical and electrical conductivity were examined by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Absorption (EDAX), Fourier transform infrared spectroscopy (FTIR), UV and Photo Luminescence (PL) Characterization. The average particle size of the synthesized ZnO nanoparticles is calculated using the Scherrer formula and is found to be of less than 20 nm. Luminescences properties were found to be enhanced for the La and La+Ag co-doped ZnO nanoparticles.

scholarly journals Effect of Yb Concentration on the Structural, Magnetic and Optoelectronic Properties of Yb Doped ZnO: First Principles Calculation

2021 ◽  
Author(s):  
Mohamed Achehboune ◽  
Mohammed Khenfouch ◽  
Issam Boukhoubza ◽  
Issam Derkaoui ◽  
Bakang Moses Mothudi ◽  
...  
Keyword(s):  
Band Gap ◽  
Conduction Band ◽  
Density Functional ◽  
Blue Shift ◽  
First Principles Calculation ◽  
Theoretical Research ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Doped Zno ◽  
Good Agreement

Abstract Density functional theory-based investigation of the electronic, magnetic, and optical characteristics in pure and ytterbium (Yb) doped ZnO has been carried out by the plane-wave pseudopotential technique with generalized gradient approximation. The calculated lattice parameters and band gap of pure ZnO are in good agreement with the experimental results. The energy band-gap increases with the increase of Yb concentration. The Fermi level moves upward into the conduction band after doping with Yb, which shows the properties of an n-type se miconductor. New defects were created in the band-gap near the conduction band attributed to the Yb-4f states. The magnetic properties of ZnO were found to be affected by Yb doping; ferromagnetic property was observed for 4.17% Yb due to spin polarization of Yb-4f electrons. The calculated optical properties imply that Yb doped causes a blue shift of the absorption peaks, significantly enhances the absorption of the visible light, and the blue shift of the reflectivity spectrum was observed. Besides, a better transmittance of approximately 88% was observed for 4.17% Yb doped ZnO system. The refractive index and the extinction coefficient were observed to decrease as the Yb dopant concentration increased. As a result, we believe that our findings will be useful in understanding the doping impact in ZnO and will motivate further theoretical research.

scholarly journals Facile Microemulsion Synthesis of Vanadium-Doped ZnO Nanoparticles to Analyze the Compositional, Optical, and Electronic Properties

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 821 ◽  
Author(s):  
H.S. Ali ◽  
Ali Alghamdi ◽  
G. Murtaza ◽  
H.S. Arif ◽  
Wasim Naeem ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Attenuated Total Reflection ◽  
Lattice Parameters ◽  
Average Particle ◽  
Structural Morphology ◽  
Wurtzite Phase ◽  
X Ray ◽  
Doped Zno

In this work, microemulsion method has been followed to synthesize vanadium-doped Zn1−xVxO (with x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.10) nanoparticles. The prepared samples are characterized by several techniques to investigate the structural, morphology, electronic, functional bonding, and optical properties. X-ray diffractometer (XRD) analysis confirms the wurtzite phase of the undoped and V-doped ZnO nanoparticles. Variation in the lattice parameters ensures the incorporation of vanadium in the lattice of ZnO. Scanning electron microscopy (SEM) shows that by increasing contents of V ions, the average particle size increases gradually. X-ray Absorption Near Edge Spectroscopy (XANES) at the V L3,2 edge, oxygen K-edge, and Zn L3,2 edge reveals the presence and effect of vanadium contents in the Zn host lattice. Furthermore, the existence of chemical bonding and functional groups are also asserted by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). UV–Visible analysis shows that by increasing V+ contents, a reduction up to 2.92 eV in the energy band gap is observed, which is probably due to an increase in the free electron concentration and change in the lattice parameters.

scholarly journals Unravelling the Role of Synthesis Conditions on the Structure of Zinc Oxide-Reduced Graphene Oxide Nanofillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2149 ◽  
Author(s):  
Zélia Alves ◽  
Cláudia Nunes ◽  
Paula Ferreira
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
Zinc Acetate ◽  
Zinc Acetate Dihydrate ◽  
Average Particle Size ◽  
Antimicrobial Activities ◽  
Average Particle ◽  
Zno Nanostructures ◽  
Synthesis Conditions

The diversity of zinc oxide (ZnO) particles and derived composites applications is highly dependent on their structure, size, morphology, defect amounts, and/or presence of dopant molecules. In this work, ZnO nanostructures are grown in situ on graphene oxide (GO) sheets by an easily implementable solvothermal method with simultaneous reduction of GO. The effect of two zinc precursors (zinc acetate (ZA) and zinc acetate dihydrate (ZAD)), NaOH concentration (0.5, 1 or 2 M), and concentration (1 and 12.5 mg/mL) and pH (pH = 1, 4, 8, and 12) of GO suspension were evaluated. While the ZnO particle morphology shows to be precursor dependent, the average particle size length decreases with lower NaOH concentration, as well as with the addition of a higher basicity and concentration of GO suspension. A lowered band gap and a higher specific surface area are obtained from the ZnO composites with higher amounts of GO suspension. Otherwise, the low concentration and the higher pH of GO suspension induce more lattice defects on the ZnO crystal structure. The role of the different condition parameters on the ZnO nanostructures and their interaction with graphene sheets was observed to tune the ZnO–rGO nanofiller properties for photocatalytic and antimicrobial activities.

Blue shift in absorption edge and widening of band gap of ZnO by Al doping and Al–N co-doping

2015 ◽  
Vol 644 ◽  
pp. 528-533 ◽  
Author(s):  
Qinghu You ◽  
Hua Cai ◽  
Zhigao Hu ◽  
Peipei Liang ◽  
Slawomir Prucnal ◽  
...  
Keyword(s):  
Band Gap ◽  
Absorption Edge ◽  
Blue Shift ◽  
Al Doping ◽  
Co Doping

Co-Doped ZnO Nano-Agglomerates as a Potential Scaffold for Non-Enzymatic Hydrogen Peroxide Sensing

2021 ◽  
Vol 13 (9) ◽  
pp. 1732-1738
Author(s):  
Ahmad Umar ◽  
Ramesh Kumar ◽  
Rajesh Kumar ◽  
Ahmed A. Ibrahim ◽  
Mohsen A. M. Alhamami ◽  
...  
Keyword(s):  
Hexagonal Phase ◽  
Average Particle Size ◽  
Solution Process ◽  
Average Particle ◽  
Spherical Nanoparticles ◽  
Cyclic Voltammetric ◽  
Wurtzite Hexagonal Phase ◽  
Dynamic Concentration ◽  
Doped Zno ◽  
Co Doped

Co-doped ZnO nano-agglomerates were synthesized by a facile solution process. Several characterization techniques revealed the successful doping of the ZnO by Co ions. FESEM results showed the agglomeration of the Co-doped ZnO nanoparticles to form large-sized nano-agglomerates. The diameters of the spherical nanoparticles and the agglomerates were not found to be uniform. The diameters of the nano-agglomerates ranged from ~25 nm–120 nm. XRD spectrum confirmed the Wurtzite hexagonal phase of ZnO in Co-doped ZnO nanoagglomerates. The average particle size for Co-doped ZnO nano-agglomerates was 20.68 nm. The sensing parameters were examined by using Co-doped ZnO nano-agglomerates modified gold electrode through cyclic voltammetric and amperometric analysis. The sensitivity of 70.73 μAmM−1cm−2 and very low-detection limit of 0.2 μM was observed for H2O2. The corresponding linear dynamic concentration range was 0.2–1633 μM. The excellent sensing activities of the Co-doped ZnO nano-agglomerates for H2O2 were attributed to the improved intrinsic electric properties and increased inner defects density, particularly near the interface region.

scholarly journals Decolourization of crystal violet using nano-sized novel fluorite structure Ga 2 Zr 2− x W x O 7 photocatalyst under visible light irradiation

2020 ◽  
Vol 7 (3) ◽  
pp. 191632 ◽  
Author(s):  
H. A. Abbas ◽  
Rabab A. Nasr ◽  
Rund Abu-Zurayk ◽  
Abeer Al Bawab ◽  
Tarek S. Jamil
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Crystal Violet ◽  
Average Particle Size ◽  
Fluorite Structure ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Fluorite Phase ◽  
Average Particle ◽  
Light Illumination

Fluorite-type Zr-based oxides with the composition Ga 2 Zr 2− x W x O 7 ( x = 0, 0.05, 0.1, 0.15 and 0.2) were prepared using the citrate technique. Appropriate characterizations of all prepared materials were carried out. X-ray diffraction clarified that the undoped and W-doped Ga 2 Zr 2 O 7 samples were crystallized in the cubic fluorite phase structure. The average particle size of the samples was in the range of 3–8 nm. The lowest band gap (1.7 eV) and the highest surface area (124.3 m 2 g −1 ) were recorded for Ga 2 Zr 0.85 W 0.15 O 7. The photocatalytic impacts of the prepared systems were studied by removal of crystal violet (CV) dye employing visible light illumination and taking into consideration the initial dye concentrations, duration of visible irradiation treatment, catalysts dose and the dopant concentration. The obtained results showed higher dye removal with the boost of the catalyst dosage. W doping shifted the absorption to the visible light range by decreasing the band gap from 4.95 eV for parent Ga 2 Zr 2 O 7 to 1.7 eV for 15 mol% tungsten-doped Ga 2 Zr 2 O 7 enhancing the photocatalytic decolourization of CV from 4.2% to 83.6% for undoped and 15 mol% W-doped Ga 2 Zr 2 O 7 , respectively, at optimum operating conditions (pH 9, 1 g l −1 catalyst dose and 300 min) while heavily doped W sample containing 20 mol% W showed lower removal than 15 mol% W-doped Ga 2 Zr 2 O 7 . Complete CV degradation using 15 mol% W-doped Ga 2 Zr 2 O 7 was attained with the assistance of 25 mmol l −1 hydrogen peroxide. The reaction is aligned to pseudo-first-order kinetics. Different scavengers were introduced to decide the significance of the reactive species in CV degradation. O 2 − ∙ and h + had the major role in the degradation of CV by Ga 2 Zr 2− x W x O 7 system compared with HO • .

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