scholarly journals Photoinduced interfacial charge transfer processes in solar photocatalysis degradation of methylene blue using nanostructured ZnO

2019 ◽  
Vol 15 (34) ◽  
pp. 153-161
Author(s):  
Zainab F. AL- Bawi
Keyword(s):  
Thin Film ◽  
Methylene Blue ◽  
Reaction Rate Constant ◽  
Zno Thin Film ◽  
X Ray Diffraction ◽  
Sunlight Irradiation ◽  
Atomic Force ◽  
Photocatalytic System ◽  
Excellent Candidate ◽  
Interfacial Charge

In this research, design of advanced material for sunlight conversion requires focused research to obtain efficient photocatalytic system. Nanostructured ZnO was synthesized using spin coating technique. The structural, morphological and optical properties of annealed nanostructured ZnO thin film at 390 Co for 3 hours were characterized by x-ray diffraction, atomic force microscope AFM and UV-VIS spectrophotometer. Nanostructured ZnO was applied for removal Methylene Blue (MB) dye from water using sunlight induced photocatalytic process. Overall degradation of MB/ZnO was achieved after 120 minutes of sunlight irradiation while it needs more time for MB alone. The reaction rate constant fit pseudo first order for MB/ZnO degradation was 0.031 min−1 compared to 0.018 min-1 using blank sample. Annealed nanostructured ZnO thin film was considered as an excellent candidate to enhance photocatalytic system to convert sunlight to chemical energy based on interfacial charges transfer.

The Effect of Solution Temperature on Electrodeposit-ZnO Thin Film

2013 ◽  
Vol 594-595 ◽  
pp. 1131-1135 ◽  
Author(s):  
Fariza Mohamad ◽  
Connie Anak Abang ◽  
Nik Hisyamudin Muhd Nor ◽  
Masanobu Izaki
Keyword(s):  
Thin Film ◽  
Zinc Nitrate ◽  
Solution Temperature ◽  
Zno Thin Film ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Nitrate Hydrate ◽  
Atomic Force ◽  
Xrd Patterns

Zinc Oxide (ZnO) has been successfully electrodeposited on a fluorine doped tin oxide (FTO) coated glass substrates using a simple aqueous solution containing zinc nitrate hydrate by low temperature galvanostatic electrolysis. The solution temperature of zinc nitrate hydrate was varied from 60°C to 75°C in order to investigate the effect of solution temperature on electrodeposit-ZnO thin film. The properties of ZnO film were investigated by X-ray diffraction (XRD), Field-Emission Scanning electron microscope (FE-SEM) and Atomic force microscopy (AFM). The solution temperature shows a significant effect on structural and morphological of deposit-ZnO. The XRD patterns exhibited the increment of (002)-ZnO peak when the solution temperature increased and the highest peak was observed at 75°C. The morphology of ZnO was changed from planar to nanopillar with the solution temperature. In conclusion, ZnO nanopillar with an excellent structural properties was obtained at solution temperature of 75°C.

Effect of ultra-thin Cu underlayer on the magnetic properties of Ni80Fe50 / Fe50Mn50 films

1999 ◽  
Vol 562 ◽  
Author(s):  
C. Liu ◽  
L. Shen ◽  
H. Jiang ◽  
D. Yang ◽  
G. Wu ◽  
...  
Keyword(s):  
Thin Film ◽  
Atomic Force Microscopy ◽  
Exchange Bias ◽  
Film Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Maximum Value ◽  
Film Roughness

ABSTRACTThe Ni80Fe20/Fe50Mn50,thin film system exhibits exchange bias behavior. Here a systematic study of the effect of atomic-scale thin film roughness on coercivity and exchange bias is presented. Cu (t) / Ta (100 Å) / Ni80Fe20 (100 Å) / Fe50Mno50 (200 Å) / Ta (200 Å) with variable thickness, t, of the Cu underlayer were DC sputtered on Si (100) substrates. The Cu underlayer defines the initial roughness that is transferred to the film material since the film grows conformal to the initial morphology. Atomic Force Microscopy and X-ray diffraction were used to study the morphology and texture of the films. Morphological characterization is then correlated with magnetometer measurements. Atomic Force Microscopy shows that the root mean square value of the film roughness exhibits a maximum of 2.5 Å at t = 2.4 Å. X-ray diffraction spectra show the films are polycrystalline with fcc (111) texture and the Fe50Mn50 (111) peak intensity decreases monotonically with increasing Cu thickness, t. Without a Cu underlayer, the values of the coercivity and loop shift are, Hc = 12 Oe and Hp = 56 Oe, respectively. Both the coercivity and loop shift change with Cu underlayer thickness. The coercivity reaches a maximum value of Hc= 36 Oe at t = 4 Å. The loop shift exhibits an initial increase with t, reaches a maximum value of HP = 107 Oe at t = 2.4 Å, followed by a decrease with greater Cu thickness. These results show that a tiny increase in the film roughness has a huge effect on the exchange bias magnitude.

Optimization of Tungsten Disulfide/Polypyrrole Composite as Photocatalyst in Sunlight-Asissted Photodegradation of Methylene Blue in Aqueous Solution

2021 ◽  
Author(s):  
Siti Nor Atika Baharin ◽  
Nurul Hafawati Hashim ◽  
Izyan Najwa Mohd Norsham ◽  
Syed Shahabuddin ◽  
Kavirajaa Pandian Sambasevam
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Contact Time ◽  
Oxidative Polymerization ◽  
Effective Parameters ◽  
X Ray Diffraction ◽  
Sunlight Irradiation ◽  
Initial Concentration ◽  
Tungsten Disulphide ◽  
Polypyrrole Composite

Abstract The present study highlights the sunlight-assisted photodegradation of methylene blue (MB) using tungsten disulphide/polypyrrole (WS2/PPy) composite as a photocatalyst. WS2/PPy was prepared via oxidative polymerization using ferric chloride (FeCl3) as an oxidant. Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) measurement were used to ensure the physicochemical properties of WS2/PPy. The photocatalytic efficiencies of the photocatalysts were examined by degrading methylene blue (MB) under sunlight irradiation. The results showed that the degradation efficiency of WS2/PPy was higher than the pristine PPy Several optimizations such as effect of the concentration, contact time, photocatalyst dosage and initial concentration were investigated. The results revealed that, under optimum condition of pH 3, 100 mg photocatalyst dosage, 10 ppm MB initial concentration within 180 minutes contact time, were the most effective parameters, that produced 96.15% of sunlight-assisted photodegradation in aqueous solution of MB.

Optical Functions of Thin-Film Polycrystalline Chalcopyrite CuIn1-xGaxSe2

2003 ◽  
Vol 763 ◽  
Author(s):  
Sung-Ho Han ◽  
Dean H. Levi ◽  
Hamda A. Althani ◽  
Falah S. Hasoon ◽  
Raghu N. Bhattacharya ◽  
...  
Keyword(s):  
Thin Film ◽  
Dielectric Function ◽  
Layer Structure ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Optical Functions ◽  
Atomic Force ◽  
Polycrystalline Thin Films ◽  
Cigs Solar Cells ◽  
Compare And Contrast

AbstractThe highest efficiency CuIn1-xGaxSe2 (CIGS) solar cells use thin-film polycrystalline CIGS absorber layers. We have applied variable angle spectroscopic ellipsometry (VASE) to characterize the dielectric functions of polycrystalline thin films of CIGS with Ga: (In + Ga) ratios ranging from 0.18 to 1.0. The Cu: (In + Ga) ratios in these films are approximately 0.90, which is the ratio that yields the highest efficiency CIGS devices. Spectra were measured over the energy range 0.7 to 5.0 eV at room temperatures. Models used to analyze the ellipsometry data include the full multi-layer structure of the sample, which enables us to report the actual dielectric function rather than the pseudo-dielectric function. We present data on how the critical points change with composition, and compare and contrast our results with measurements of single-crystal and bulk polycrystalline samples reported in the literature. Auger electron spectroscopy, atomic force microscopy, and X-ray diffraction have been used to verify the homogeneity, surface roughness, and phase purity, respectively.

scholarly journals Epitaxial Order Driven by Surface Corrugation: Quinquephenyl Crystals on a Cu(110)-(2×1)O Surface

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 373 ◽  
Author(s):  
Roland Resel ◽  
Markus Koini ◽  
Jiri Novak ◽  
Steven Berkebile ◽  
Georg Koller ◽  
...  
Keyword(s):  
Thin Film ◽  
Crystal Surface ◽  
Substrate Surface ◽  
Lattice Misfit ◽  
Crystallographic Structure ◽  
Initial Growth ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Lattice Matching ◽  
Atomic Force

A 30 nm thick quinquephenyl (5P) film was grown by molecular beam deposition on a Cu(110)(2×1)O single crystal surface. The thin film morphology was studied by light microscopy and atomic force microscopy and the crystallographic structure of the thin film was investigated by X-ray diffraction methods. The 5P molecules crystallise epitaxially with (201)5P parallel to the substrate surface (110)Cu and with their long molecular axes parallel to [001]Cu. The observed epitaxial alignment cannot be explained by lattice matching calculations. Although a clear minimum in the lattice misfit exists, it is not adapted by the epitaxial growth of 5P crystals. Instead the formation of epitaxially oriented crystallites is determined by atomic corrugations of the substrate surface, such that the initially adsorbed 5P molecules fill with its rod-like shape the periodic grooves of the substrate. Subsequent crystal growth follows the orientation and alignment of the molecules taken within the initial growth stage.

Facile synthesis of TiO2 film on glass for the photocatalytic removal of rhodamine B and tetracycline hydrochloride

2019 ◽  
Vol 9 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Jiaxin Li ◽  
Zhi Chen ◽  
Jianfei Fang ◽  
Qian Yang ◽  
Xiuru Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Organic Pollutants ◽  
Reaction System ◽  
Practical Application ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Photocatalytic Removal ◽  
Coating Method ◽  
Potential Applications

Photocatalysis is one of the efficient approaches for pollution control in water. However, the traditional photocatalysts used for the removal of organic pollutants are in powder form, which makes it difficult to recover them from the suspended reaction system. On the contrary, thin film photocatalyst is easy to be retrieved and possesses unique feature for practical application. In present work, stable TiO2 sol suspension was prepared and amorphous TiO2 thin film was then immobilized upon glass substrate through facile spin coating method. The thickness of film could be simply controlled by changing the number of coatings, and anatase TiO2 film could be formed after calcination. The prepared thin films were characterized with X-ray diffraction (XRD), ultravioletvisible spectrophotometry (UV-vis), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The photodegradations of organic pollutants including colored dye and colorless antibiotic were tested and found to be thickness-dependent. Additionally, the prepared film photocatalst has good stability and may have potential applications in wastewater treatment.

Assembly of thin Film Dielectrics by Sequential Adsorption Reactions of Unilamellar Inorganic Colloids

1996 ◽  
Vol 446 ◽  
Author(s):  
Mingming Fang ◽  
Chy Hyung Kim ◽  
Anthony C. Sutorik ◽  
David M. Kaschak ◽  
Thomas E. Mallouk
Keyword(s):  
Thin Film ◽  
Inorganic Materials ◽  
Silicon Surfaces ◽  
X Ray Diffraction ◽  
Alkali Cations ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sequential Adsorption ◽  
Thin Film Dielectrics ◽  
Layered Perovskites

AbstractSeveral layered inorganic materials (e.g. KCa2Nb3O10, KTiNbO5, and CsPb2Nb3O10) were prepared and their alkali cations exchanged by in aqueous acid. A fraction of the interlayer protons of HCa2Nb3O10 and HTiNbO5 can be replaced by tetra-n-butylammonium (TBA+), by reaction with TBA+OH. Intercalation of a sufficient amount of TBA+ causes complete exfoliation, and single, nanometer-thick sheets of these materials are thus obtained. By sequential adsorption of these two-dimensional colloidal polyanions and polymeric cations, monolayer sheets of layered perovskites can be stacked on silicon surfaces to give thin films of any desired thickness. The layered materials, the exfoliated colloids, and the thin film multilayers on silicon were studied by X-ray diffraction, transmission electronic microscopy (TEM), ellipsometry, and atomic force microscopy (AFM). The dielectric properties of the related bulk materials were measured, and are also discussed.

Effect of RF Power on the Formation and Morphology Evolution of ZnO Nanostructured Thin Films

2012 ◽  
Vol 576 ◽  
pp. 577-581 ◽  
Author(s):  
N.D.M. Sin ◽  
Mohamad Hafiz Mamat ◽  
Mohamed Zahidi Musa ◽  
S. Ahmad ◽  
A. Abdul Aziz ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Structural Properties ◽  
Zno Thin Films ◽  
Morphology Evolution ◽  
Zno Thin Film ◽  
Rf Power ◽  
Nanostructured Thin Films ◽  
Atomic Force ◽  
Current Voltage

The effect of RF power on the formation and morphology evolution of ZnO nanostructured thin films deposited by magnetron sputtering are presented. This project focused on electrical, optical and structural properties of ZnO thin films. The effect of variation of RF power at 50 watt-250 watt at 200 °C on glass substrate of the ZnO thin films was investigated. The thin films were examined for electrical properties and optical properties using two point probe current-voltage (I-V) measurement (Keithley 2400) and UV-Vis-NIR spectrophotometer (JASCO 670) respectively. The structural properties were characterized using field emission scanning electron microscope (FESEM) (JEOL JSM 7600F) and atomic force microscope (AFM) (Park System XE-100). The IV measurement indicated that at RF power 200 watt the conductivity of ZnO thin film show the highest. All films show high UV absorption properties using UV-VIS spectrophotometer (JASCO 670). The root means square (rms) roughness for ZnO thin film were about 4 nm measured using AFM. The image form FESEM observed that transformation of structure size started to change as the RF power increase.

Copper Doped ZnO Thin Film for Ultraviolet Photodetector with Enhanced Photosensitivity

2013 ◽  
Vol 1494 ◽  
pp. 43-49 ◽  
Author(s):  
Akshta Rajan ◽  
Kashima Arora ◽  
Harish Kumar Yadav ◽  
Vinay Gupta ◽  
Monika Tomar
Keyword(s):  
Thin Film ◽  
Sol Gel ◽  
High Porosity ◽  
Zno Thin Film ◽  
X Ray Diffraction ◽  
Uv Photodetector ◽  
Response Characteristics ◽  
Uv Illumination ◽  
Photogenerated Electrons ◽  
Doped Zno

ABSTRACTUltraviolet photoconductivity in Copper doped ZnO (Cu:ZnO) thin films synthesized by sol-gel technique is investigated. Response characteristics of Pure ZnO thin film and Cu:ZnO thin film UV photodetector with 1.3 at. wt % Cu doping biased at 5 V for UV radiation of λ = 365 nm and intensity = 24 µwatt/cm2 has been studied. Cu:ZnO UV photodetector is found to exhibit a high photocoductive gain (K = 1.5×104) with fast recovery (T90% = 23s) in comparison to pure ZnO thin film based photodetector (K = 4.9×101 and T90% = 41s). Cu2+ ions have been substituted in ZnO lattice which has been confirmed by X-ray diffraction (XRD) and Raman spectroscopy leading to lowering of dark current (Ioff ∼ 1.44 nA). Upon UV illumination, more electron hole pairs are generated in the photodetector due to the high porosity and roughness of the surface of the film which favours adsorption of more oxygen on the surface of the photodetector. The photogenerated holes recombined with the trapped electrons, increasing the concentration of photogenerated electrons in the conduction band enhancing the photocurrent (Ion ∼ 0.02 mA) of the Cu:ZnO photodetector.

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