scholarly journals Effects of PEG1000 and Sol Concentration on the Structural and Optical Properties of Sol–Gel ZnO Porous Thin Films

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1840
Author(s):  
Dong Xu ◽  
Qian Yu ◽  
Taiyun Chen ◽  
Sujuan Zhong ◽  
Jia Ma ◽  
...  

ZnO porous thin films were synthesized as antireflection coatings via a sol–gel dip-coating method with polyethylene glycol (PEG1000) utilized as a polymeric porogen on alumina transparent ceramics. The pore formation mechanism of the ZnO porous thin films was proposed through thermal and Fourier transformation infrared spectrometer (FTIR) analyses. The effect of sol concentrations on crystal structure, microstructure, and optical properties was also discussed. The experiment results indicated that all the ZnO thin films exhibited a hexagonal wurtzite structure with their preferred orientation along a (0 0 2) plane by X-ray diffraction (XRD) patterns. The grain size of the films increased from 30.5 to 37.4 nm with the sol concentration ranging from 0.2 to 1.0 M. Furthermore, scanning electron microscopy (SEM) images show that the pores on the surface were observed to first decrease as the sol concentration increased and then to disappear as the sol concentration continued to increase. The UV spectrum presents a maximum transmittance of 93.5% at a wavelength of 600 nm at a concentration of 0.6 M, which will be helpful in the practical applications of ZnO porous film on alumina transparent ceramic substrates. The pore formation mechanism of ZnO porous thin films can be ascribed to ring-like network structures between the PEG1000 and zinc oligomers under the phase separation effect.

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.


2013 ◽  
Vol 16 (1) ◽  
pp. 92-100
Author(s):  
Chien Mau Dang ◽  
Dam Duy Le ◽  
Tam Thi Thanh Nguyen ◽  
Dung Thi My Dang

In this study, we have successfully synthesized Fe3+ doped SiO2/TiO2 thin films on glass substrates using the sol-gel dip-coating method. After synthesizing, the samples were annealed at 5000C in the air for 1 hour. The characteristics and optical properties of Fe3+ doped SiO2/TiO2 films were then investigated by X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis) and Fourier transform infrared spectroscopy (FT-IR). An antifogging ability of the glass substrates coated with the fabricated film is investigated and explained by a water contact angle under visible-light. The analyzed results also show that the crystalline phase of TiO2 thin films comprised only the anatase TiO2, but the crystalline size decreased from 8.8 to 5.9 nm. We also observed that the absorption edge of Fe3+- doped SiO2/TiO2 thin films shifted towards longer wavelengths (i.e. red shifted) from 371.7nm to 409.2 nm when the Fe3+-doped concentration increased from 0 to 1 % mol.


2020 ◽  
Vol 12 (3) ◽  
pp. 388-391
Author(s):  
Raees A. Gani Shaikh ◽  
Sagar A. More ◽  
Gauri G. Bisen ◽  
Sanjay S. Ghosh

CZTS chalcopyrite semiconductor has received attention as a promising alternative as an absorber in thin-film solar cells because of the high absorption coefficient, direct bandgap (1.5 eV), nontoxic elements and sustained high electrical and optical properties. In the present work, CZTS thin film has been developed by the sol–gel spin coating method by thermal decomposition of metal ions and thiourea complexes under ambient environment. Annealing study of the above prepared CZTS thin films has been performed. The prepared CZTS samples were annealed at different temperatures 250 °C, 275 °C, 300 °C, and 325 °C respectively. Crystallographic structure, surface morphology, and optical properties were studied. XRD pattern shows the kesterite structure of the films with characteristics peaks for planes (112), (200), (220), and (312). Crystallite size, strain and dislocation densities were calculated. Sample annealed at 300 °C shows the most intense XRD peak and hence larger grain size. Grain size tends to increase as the annealing temperature increases up to 300 °C. At 325 °C SEM images show that cracks are formed in the film. At lower temperatures uniform, homogenous, smooth and densely packed films are formed. Raman spectroscopy is used to determine phase purity because many of binary and ternary chalcogenides show XRD peaks at similar positions to that of CZTS. A single peak at 336 cm–1 shows the pure kestrite phase of CZTS for all films.


2015 ◽  
Vol 723 ◽  
pp. 528-531
Author(s):  
Jun Wang ◽  
Ling Yun Bai

TiO2 thin films were prepared on glass substrates by sol-gel method. The effect of withdraw speed on the thickness and optical properties of TiO2 thin films was investigated. The films were transparent in the visible wavelength. The thickness of the TiO2 films was increased from 90 nm for the withdraw speed of 1000 μm/s to 160 nm for the withdraw speed of 2000 μm/s. While, The refractive index of the TiO2 thin film decreased from 2.38 to 2.07. It may be due to the porosity of the film was increased. The optical band-gap of the films was around 3.45 eV.


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