https://iopscience.iop.org/article/10.1088/2053-1591/ab5bf1/pdf

Effect of Li doping on conductivity and band gap of nickel oxide thin film deposited by spin coating technique

Nanostructured thin films of Nickel oxide NiO were synthesized using spray coating method. The samples were irradiated at different γ-doses by Co-60 radioisotope. The obtained films were studied using X-ray diffraction (XRD), scanning electron microscopy, UV–visible spectrophotometry, Raman spectroscopy, photoluminescence (PL) spectroscopy and FT-IR. The experimental results demonstrated that the irradiation of NiO led to significant changes. XRD and Raman spectroscopy demonstrate that the as-deposited NiO samples show a cubic structure with (111) preferred orientation common at all gamma radiation doses. The optical energy gaps of the samples were found to decrease when increasing the γ ray dose, the Eg value decreases from 3.84 eV for as deposited NiO thin film to 3.60 eV for sample irradiated at 50 kGy. Scanning electron microscope (SEM) image of sprayed NiO films shows the high porosity and the presence of microcavities in surface of films.

Investigation of the properties of nanostructured nickel oxide NiO thin films irradiated at different γ-doses

Effects of interfacial energy level alignment on carrier dynamics and photovoltaic performance of inverted perovskite solar cells

Concrete has a tremendous influence on the environment since the majority of its composition is cement, which is a material that emits high levels of carbon dioxide. It is possible for concrete construction to have a lower impact on the environment if the usage of cement is reduced as much as possible by the addition of mineral admixtures such as fly ash, without sacrificing the durability standards at the same time. The disposal of fly ash, which is produced by power stations that burn coal for fuel, is recognised as one of the most pressing environmental issues. When there is a simultaneous increase in the amount of fly ash and a decline in the capacity of landfills, it is much more difficult to find a solution to this problem. The research on fly ash admixed concrete is analysed and discussed in this publication. There have been many studies conducted on the topic of fly ash concrete and its beneficial effects. In this study, the fresh and hardened properties of fly ash concrete, such as mechanical properties, durability parameters, and microstructural characteristics, are studied. Additionally, the useful application case studies of fly ash concrete published by the American Coal Ash Association are also summarised. 

Fly ash for sustainable construction: A review of fly ash concrete and its beneficial use case studies

The contamination of water from industrial pollutants is the most significant concern for environment. Semiconductors have been at forefront of effective elimination of pollutants from waste water, with the tuning of bandgap and improving the photocatalytic activity. This work elaborates the hydrothermal synthesize of highly stable Nickel Oxide (NiO) and Vanadium-doped Nickel Oxide (V-NiO) nanoparticles. The undoped and doped Nickel Oxide nanoparticles were characterized for structural, morphological, thermal and optical properties. X-ray diffraction pattern reveals the V-NiO stabilized in cubic structure. Morphological analysis demonstrates that upon Vanadium doping NiO particles transform from network like structure to spherical nanoparticles. NiO and V-NiO nanoparticles have an average crystallite size of 42 nm and 26 nm which are well matched with particle size calculated from transmission electron micrographs. The photoluminescence study reveals that the Vanadium substitution specifically reduces the rate of recombination in NiO. The V-NiO catalysts exhibited noticeable red shift of absorption spectrum to the visible region in comparison with pure NiO. The functional groups were studied using Fourier Transform Infrared Spectroscopy (FTIR). The photocatalytic study by degradation of Xylenol Orange (XyO) under sunlight irradiation unveils that photocatalytic activity of NiO is enhanced on vanadium doping. Reaction kinetics investigation of XyO degradation revealed that the reaction obeys the pseudo-zero-order model with improved rate constant of 0.115 mol L−1S−1 and 0.225 mol L−1S−1 for NiO and V-NiO, respectively. The retention of high performance and structural stability of photocatalysts after four consecutive degradation cycles implies the reusability of the catalyst. Consequently, the V-NiO with high photocatalytic activity with improved cyclic stability is able to provide as a promising material in the field of environmental remediation.

Enhanced photocatalytic activity on Vanadium-doped NiO nanostructures in natural sunlight

In this study, pristine nickel oxide (NiO), copper-doped NiO (Cu–NiO) and vanadium-doped NiO (V–NiO) thin films were deposited using reactive RF magnetron co-sputtering as a function of dopant sputtering power. Cu (0–8 at%) and V (0–1 at%) were doped into the NiO lattice by varying the sputtering power of Cu and V in the range of 5–15 W. The effect of dopant concentration on optoelectronic behavior is investigated by UV–Vis–NIR spectrophotometer and Hall measurements. XRD analysis showed that the preferred orientation of the cubic phase for undoped NiO changes from (200) to (111) plane when the sputtering parameters are varied. The observed changes in the lattice parameters and bonding states of the doped NiO indicate the substitution of Ni ions by monovalent Cu and trivalent V ions. The optical bandgap of pristine NiO, Cu–NiO, and V–NiO was found to be 3.6, 3.45, and 3.05 eV, respectively, with decreased transmittance and resistivity. Further analysis using SEM and AFM described the morphological behavior of doped NiO thin films and Raman spectroscopy indicated the structural changes on doping. These findings would be helpful in fabricating solid-state solar cells using doped NiO as efficient hole transporting material.

Role of copper/vanadium on the optoelectronic properties of reactive RF magnetron sputtered NiO thin films

Sulfate attack on concrete structures is a major durability concern wherein concrete interacts with marine water, swamp water, groundwater, sewage water, freshwater, etc. In this study, the supplementary cementitious materials such as fly ash (FA) and nanoparticles are together incorporated into conventional concrete aiming to enhance the resistance of concrete against the penetration of sulfates. The present work is focused to understand the degradation in FA concrete modified with nanoparticles by surface sulfate attack. Concrete mix such as FA and FA modified with 2 wt% nano-TiO2 (FAT), nano-CaCO3 (FAC), and 1:1 ratio of nano-TiO2 to nano-CaCO3 (FATC) was fabricated. The specimens were exposed in 3% of ammonium and sodium sulfate for 90 days. The deterioration effects and changes in microstructural properties in all the specimens were comparatively studied. Results showed FAT, FAC, and FATC concrete have been deteriorated in ammonium and sodium sulfate solution compared with FA concrete. Partial replacement of cement with fly ash decreases the quantity of freely available reactive aluminates. Consumption of free lime by the fly ash prevents to react with sulfate. The enhanced properties of fly ash concrete against sulfate attack could be achieved with less C3A content thus reducing the available Ca(OH)2 and reducing the possibility of development of deleterious ettringite and gypsum.

Viswanathan Kanagasabai

Papers

Role of copper/vanadium on the optoelectronic properties of reactive RF magnetron sputtered NiO thin films

Investigation on surface sulfate attack of nanoparticle-modified fly ash concrete

Investigating biological impact of HAp from goat femur reinforced with Zr–Ag for bone tissue engineering application