scholarly journals Aluminum doping tunes band gap energy level as well as oxidative stress-mediated cytotoxicity of ZnO nanoparticles in MCF-7 cells

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohd Javed Akhtar ◽  
Hisham A. Alhadlaq ◽  
Aws Alshamsan ◽  
M.A. Majeed Khan ◽  
Maqusood Ahamed
Keyword(s):  
Oxidative Stress ◽  
Energy Level ◽  
Band Gap ◽  
Zno Nanoparticles ◽  
Band Gap Energy ◽  
Aluminum Doping ◽  
Gap Energy ◽  
Mcf 7

The Nanocrystallinity Enhancement and Optical Characteristics of Pre-Hydrothermally Treated ZnO Nanoparticles

2012 ◽  
Vol 557-559 ◽  
pp. 468-471 ◽  
Author(s):  
Akhmad Herman Yuwono ◽  
Ghiska Ramahdita ◽  
Nofrijon Sofyan
Keyword(s):  
Band Gap ◽  
Crystallite Size ◽  
Hydrothermal Treatment ◽  
Zno Nanoparticles ◽  
Treatment Duration ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Nanocrystallite Size ◽  
Gel Technique

In the current research, ZnO nanoparticles have been synthesized via sol-gel technique assisted by a pre-hydrothermal treatment at 150oC with various holding time of 0, 24, 48 and 72 hours. This route was specifically aimed at investigating the effect of this treatment on the nanocrystallite size, crystallinity and band gap energy of the resulting nanoparticles. The results of investigation showed that an increasing of pre-hydrothermal treatment duration from 0 to 72 hours has increased the crystallite size of ZnO nanoparticles from 3.47 to 13.85 nm, and decreased the band gap energy from 3.10 to 3.08 eV.

scholarly journals PREPARATION AND CHARACTERIZATION OF ZnO NANOPARTICLES BY SOLVENT FREE METHOD

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Savka Janković ◽  
Dragana Milisavić ◽  
Tanja Okolić ◽  
Dijana Jelić
Keyword(s):  
Band Gap ◽  
Zno Nanoparticles ◽  
Band Gap Energy ◽  
Zinc Nitrate ◽  
Solvent Free ◽  
Band Model ◽  
Nitrate Hexahydrate ◽  
Gap Energy ◽  
Tauc Plot

ZnO nanoparticles have numerous applications as photo catalysts, gas sensors, UV lasers, as optoelectronic and microelectronic devices or in cosmetic field. ZnO nanoparticles were synthesized by solvent free method using zinc nitrate hexahydrate as precursor and glycerol as dispersant, without solvent present. This method proved to be very simple, economic and ecofriendly. Zinc nitrate and glycerol were mixed in different ratio in order to avoid and overcome a possibility of agglomeration. Characterization of samples was performed by UV/VIS and FTIR spectrophotometry. The strongest absorption appeared at wavelength 206 nm. Using combination of UV/VIS spectrophotometry and hyperbolic band model (HBM) particles size of ZnO particles were evaluated to 2.06 nm. Additionally, using Tauc plot, a band gap energy was determined. Band gap energy of ZnO nanoparticles amounted to 5.00 eV. IR spectrum showed existence of ZnO in interval 600- 400 cm-1.

The Effect of Precursor Mixing Temperature during Precipitation Process on the Size of ZnO Nanoparticles and the Dispersion of ZnO@SiO2 Core-Shell Nanostructure

2014 ◽  
Vol 525 ◽  
pp. 108-116
Author(s):  
Akhmad Herman Yuwono ◽  
Nofrijon Sofyan ◽  
Vincentius Hamdani ◽  
Amalia Sholehah ◽  
Muhammad Arief
Keyword(s):  
Band Gap ◽  
Zno Nanoparticles ◽  
Light Emission ◽  
Surface Active Agent ◽  
Active Agent ◽  
Band Gap Energy ◽  
Cell Labeling ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Gap Energy

ZnO nanoparticles have been used for many applications, including in cell labeling application. Its light emission can be used to determine and identify biology cells. Wet chemical precipitation method has been successfully done to synthesize the nanoparticle and it was subsequently continued by encapsulating with silica to keep ZnO stabilized in water to be properly used in cell labeling application. Varying precipitation temperatures has been performed to control the nanoparticle size and the addition of F127 surface active agent was carried out to prevent the agglomeration. The results showed the smallest nanoparticle (3.49 nm) was obtained from the process with temperature of 25oC, with the highest band gap energy, 3.12 eV. On the other hand, the largest nanoparticle (13.16 nm) was obtained from synthesis at temperature of 65oC, with the lowest band gap energy, 3.08 eV. These levels of band gap energy are potentially suitable for cell labeling application.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

scholarly journals Synthesis and Optical Properties of B-Mg co-Doped ZnO Nanoparticles

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 882
Author(s):  
Yuechan Li ◽  
Yongli Li ◽  
An Xie
Keyword(s):  
Optical Properties ◽  
Zno Nanoparticles ◽  
Great Influence ◽  
Structure Study ◽  
Band Gap Energy ◽  
One Pot ◽  
Gap Energy ◽  
Doping Impurity ◽  
Shrinkage Effect ◽  
Co Doped

Doping impurity into ZnO is an effective and powerful technique to tailor structures and enhance its optical properties. In this work, Zn1−xMgxO and Zn1−x−yMgxByO nanoparticles (x = 0, 0.1, 0.2, 0.3, 0.4; y = 0, 0.02, 0.04) were synthesized via one-pot method. It shows that the Mg and B dopants has great influence on crystallinity and surface morphology of ZnO nanoparticles, without changing the wurtzite structure of ZnO. The band structure study indicates that the competition of Conductive Band (CB) shift, Burstein–Moss (B-M) shift and Shrinkage effect will cause the band gap energy change in ZnO.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

Sign in / Sign up

Export Citation Format

Share Document