scholarly journals Structural, morphological and optical studies of sol-gel engineered Sm3+ activated ZnO thin films for photocatalytic applications

2020 ◽  
Vol 21 (3) ◽  
pp. 433-439
Author(s):  
T. Kiran ◽  
H. M. Parveez Ahmed ◽  
Noor Shahina Begum ◽  
Karthik Kannan ◽  
D. Radhika

Rare earth (RE) ions activated ZnO thin films were prepared via sol-gel route and the thin films be categorized by various techniques. X-ray diffraction (XRD) studies display the hexagonal wurtzite structure of the prepared thin films. Scherrer's formula was utilized to calculate the average crystallite size (25–40 nm) with different Sm3+ concentrations. The optical energy gap was calculated by Diffused Reflectance spectra (DRS). The Acid Red (AR) dye was degraded under ultraviolet (UV) light irradiation with ZnO: Sm3+(1-9 mol %) nanostructured thin films  and the highest photodegradation (95 %) was observed for 7 mol %  of  Sm3+ doped ZnO catalyst. All the obtained results suggest that prepared material could be a prominent material as photocatalyst.

2021 ◽  
pp. 130-137
Author(s):  
Yasir Yahya Kasim ◽  
Ghazwan Ghazi Ali ◽  
Marwan Hafeedh Younus

This work investigates the structural, optical, and surface properties of ZnO thin films prepared by sol-gel method. The effect on waveguide sensor was examined at different irradiation durations of alpha particles. The X-ray diffraction (XRD) measurements revealed that the crystalline phase of ZnO thin films does not change after irradiation and showed a hexagonal structure of wurtzite type with an orientation toward (002). Moreover, ZnO thin films absorbance was increased with increasing irradiation time, whereas the transmittance was decreased. Additionally, increasing the irradiation time of alpha particles caused an increase in the extinction coefficient and the imaginary part,  while the optical energy gap of the ZnO samples was decreased. Finally, the maximum value of sensitivity was 42%, found at 6 min of irradiation duration.


2014 ◽  
Vol 926-930 ◽  
pp. 274-277
Author(s):  
Shu Cui ◽  
Cheng You Liu ◽  
Xiao Tian Li

ZnO thin films were deposited on simple glass substrate by sol-gel technique. The structure, morphology and luminescence of the annealed ZnO thin films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), ultra-violet spectrometer (UVS) and photoluminescence (PL) spectroscopy, respectively. The XRD experiments shows that all of the samples annealed at 300°C, 400°C, 500°C have a hexagonal wurtzite structure. Absorption spectrum shows that all the samples have high transmittance in the visible range and have a strong absorption near the band edge of ZnO. The morphology of the samples studied by the AFM shows an increase in the annealing temperature causes the surface flatter and the grain size larger. The PL spectrum shows obvious peak near 380nm.


2019 ◽  
Vol 17 (40) ◽  
pp. 95-107
Author(s):  
Selma M. H. Al-Jawad

Pure and Fe-doped zinc oxide nanocrystalline films were preparedvia a sol–gel method using -C for 2 h.The thin films were prepared and characterized by X-ray diffraction(XRD), atomic force microscopy (AFM), field emission scanningelectron microscopy (FE-SEM) and UV- visible spectroscopy. TheXRD results showed that ZnO has hexagonal wurtzite structure andthe Fe ions were well incorporated into the ZnO structure. As the Felevel increased from 2 wt% to 8 wt%, the crystallite size reduced incomparison with the pure ZnO. The transmittance spectra were thenrecorded at wavelengths ranging from 300 nm to 1000 nm. Theoptical band gap energy of spin-coated films also decreased as Fedoping concentration increased. In particular, their optical band gapenergies were 3.75, 3.6, 3.5, 3.45 and 3.3 eV doping concentration of0%, 2%, 4%, 6% and 8% Fe, respectively. The performance of thepure and doped ZnO thin films was examined for the photocatalyticactivity using organic dyes (methyl orange, methyl blue, methylviolet). The samples ZnO with concentration of Fe showed increasedphotocatalytic activity with an optimal maximum performance at0.8 wt%.


2018 ◽  
Vol 73 (5) ◽  
pp. 441-452 ◽  
Author(s):  
Nripasree Narayanan ◽  
N.K. Deepak

AbstractHighly transparent and conducting Zinc oxide (ZnO) thin films doped with Praseodymium (Pr) were deposited on glass substrates by using the spray pyrolysis method. The X-ray diffraction (XRD) analysis revealed the polycrystallinity of the deposited films with a hexagonal wurtzite structure, whereas the energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the incorporation of Pr in the films. The optical energy gap decreased by Pr doping due to the merging of the conduction band with the impurity bands formed within the forbidden gap. The room temperature photoluminescence spectra of the Pr-doped film showed enhancement of visible emission, suggesting efficient luminescent downshifting. The photocatalytic activity of the Pr-doped films is higher than that of undoped films due to the effective suppression of the rapid recombination of the photo-generated electron-hole pairs. The impurity levels formed within the forbidden gap act as efficient luminescent centers and electron traps, which lead to luminescent downshifting and enhanced photocatalytic activity.


2017 ◽  
Vol 73 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Zohra Nazir Kayani ◽  
Iqra Shah ◽  
Bareera Zulfiqar ◽  
Saira Riaz ◽  
Shahzad Naseem ◽  
...  

AbstractCobalt-doped ZnO thin films have been deposited using a sol–gel route by changing the number of coats on the substrate from 6 to 18. This project deals with various film thicknesses by increasing the number of deposited coats. The effect of thickness on structural, magnetic, surface morphology and optical properties of Co-doped ZnO thin film was studied. The crystal structure of the Co-doped ZnO films was investigated by X-ray diffraction. The films have polycrystalline wurtzite hexagonal structures. A Co2+ ion takes the place of a Zn2+ ion in the lattice without creating any distortion in its hexagonal wurtzite structure. An examination of the optical transmission spectra showed that the energy band gap of the Co-doped ZnO films increased from 3.87 to 3.97 eV with an increase in the number of coatings on the substrate. Ferromagnetic behaviour was confirmed by measurements using a vibrating sample magnetometer. The surface morphology of thin films was assessed by scanning electron microscope. The grain size on the surface of thin films increased with an increase in the number of coats.


Author(s):  
WASI KHAN ◽  
Z. A. KHAN ◽  
A. A. SAAD ◽  
S. SHERVANI ◽  
A. SALEEM ◽  
...  

Undoped and Al-doped ZnO (AZO) nanoparticles (NPs) have been successfully synthesized by the simple sol-gel method. The NPs have been characterized by a number of techniques as x-ray diffraction (XRD), UV-visible spectroscopy and scanning electron microscopy (SEM) at room temperature for 0%, 0.5%, 1% and 2% of Al concentration. The structural characteristics were examined using XRD and SEM with EDS. XRD analysis reveals that all samples crystallizes in polycrystalline nature with wurtzite lattice and exhibit no other impurity phase. The average crystallite size decreases with increase in Al concentration. The absorption spectra indicate increase in optical energy gap (Eg) with increase in Al ion doped into the ZnO lattice site.


2016 ◽  
Vol 675-676 ◽  
pp. 241-244 ◽  
Author(s):  
Tanattha Rattana ◽  
Sumetha Suwanboon ◽  
Chittra Kedkaew

Ni-doped ZnO thin films were prepared on glass slide substrates by a sol-gel dip coating method with different Ni doping concentrations (0-33 mol%). The effect of Ni doping concentration on structural, surface morphology and optical properties of the thin films was characterized by XRD, FESEM and UV-Vis spectrophotometer. The XRD results indicated that pure ZnO thin film exhibited a hexagonal wurtzite structure. Ni (OH)2 phase were observed at a high Ni doping concentration. The FESEM images showed that the surface morphology and surface roughness were sensitive to the Ni doping concentration. The optical transmission measurements were observed that the transmittance decreased with increasing the Ni doping concentration.


2014 ◽  
Vol 32 (4) ◽  
pp. 688-695 ◽  
Author(s):  
Munirah Munirah ◽  
Ziaul Khan ◽  
Mohd. Khan ◽  
Anver Aziz

AbstractThis paper describes the growth of Cd doped ZnO thin films on a glass substrate via sol-gel spin coating technique. The effect of Cd doping on ZnO thin films was investigated using X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence spectroscopy, I–V characteristics and field emission scanning electron microscopy (FESEM). X-ray diffraction patterns showed that the films have preferred orientation along (002) plane with hexagonal wurtzite structure. The average crystallite sizes decreased from 24 nm to 9 nm, upon increasing of Cd doping. The films transmittance was found to be very high (92 to 95 %) in the visible region of solar spectrum. The optical band gap of ZnO and Cd doped ZnO thin films was calculated using the transmittance spectra and was found to be in the range of 3.30 to 2.77 eV. On increasing Cd concentration in ZnO binary system, the absorption edge of the films showed the red shifting. Photoluminescence spectra of the films showed the characteristic band edge emission centred over 377 to 448 nm. Electrical characterization revealed that the films had semiconducting and light sensitive behaviour.


2021 ◽  
Author(s):  
Ştefan Ţălu ◽  
Samah Boudour ◽  
Idris Bouchama ◽  
Bandar Astinchap ◽  
Hamta Ghanbaripour

Abstract A multifractal analysis has been performed on the three-dimensional surface microtexture of the ZnO thin films doped with Mg deposited by sol-gel spin coating on glass substrates. The effects of Mg doping element with amounts of 0, 2, 4, and 5 % on structural and morphological properties of the coated films were investigated. From the X-ray diffraction pattern analysis, it was found that the obtained thin films had a polycrystalline hexagonal wurtzite structure with preferential c-axis orientation and increased grain size with increasing the Mg doping. From scanning electron microscopy (SEM) analysis, it can be concluded that the surface of coated thin films had dense and uniformly distributed grains of nanoscale without any cracks over all surfaces of coated firms. From atomic force microscope (AFM) analysis, it can be also concluded that the surface of coated thin films had a dense columnar grain growth uniformly distributed over the entire 1 µm ⋅ 1 µm - scanned area. The surface microtexture was characterized in terms of multifractal analysis.


2021 ◽  
Vol 21 (3) ◽  
pp. 1560-1569
Author(s):  
K. Moorthy ◽  
S. S. R. Inbanathan ◽  
C. Gopinathan ◽  
N. P. Lalla ◽  
Abdulaziz Ali Alghamdi ◽  
...  

Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10−3 and 1.14×10−3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.


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