Photoluminescence of Sol-Gel Synthesized ZnO Nanostructures

2021 ◽  
Vol 885 ◽  
pp. 121-126
Author(s):  
Erasto Vergara Hernández ◽  
Brenda Carolina Pérez Millán ◽  
Yael Valdemar Torres Torres ◽  
César Eduardo Cea Montufar

Zinc oxide nanostructures have potentially interesting optical properties, which make them candidates for use in applications within the area of optoelectronics; their synthesis can be carried out through low-cost methods, such as sol gel, among many others. In addition, depending on the synthesis method, its shape and size, ZnO nanostructures can present emissions in the ultraviolet (UV) and visible region. By doping with elements such as carbon, silver, copper or some rare earth, for example, erbium, terbium or neodymium, the optical properties of ZnO can be adjusted and controlled to be able to be applied in the production of biosensors, photodetectors and even sensors of white light. In this research work, a review is presented on the nature of the optical transition mechanisms that occur in the ZnO nanostructures synthesized by the sol-gel method.

2013 ◽  
Vol 667 ◽  
pp. 329-332 ◽  
Author(s):  
A.N. Afaah ◽  
Zuraida Khusaimi ◽  
Mohamad Rusop

This paper presents a review on synthesis, structure, and growth mechanisms of one-dimensional nanostructures of ZnO. Solution-based method is a potential deposition technique for large-scale production as its advantages; the low cost, the simplicity of experimental set-up, and the low operating temperature. Mist-atomiser technique is one of the solution-based methods in synthesizing optimized ZnO nanostructures. Doping will lead for better properties of ZnO, which result to wide application area. Nanostructured ZnO is important in promising areas of application which devices utilizing nanostructures such as gas sensors and solar cells, since it is fairly easy to fabricate such forms of ZnO nanostructures, which have good charge carrier transport properties and high crystalline quality.


RSC Advances ◽  
2019 ◽  
Vol 9 (26) ◽  
pp. 14638-14648 ◽  
Author(s):  
Klinton Davis ◽  
Ryan Yarbrough ◽  
Michael Froeschle ◽  
Jamel White ◽  
Hemali Rathnayake

A reliable and simple sol–gel synthesis followed by a solvent-driven, shape controlled, crystal growth process to make ZnO nanostructures is demonstrated.


2021 ◽  
Vol 24 (3) ◽  
pp. 38-42
Author(s):  
Marwa Mudfer Alqaisi ◽  
◽  
Alla J. Ghazai ◽  

In this work, pure Zinc oxide and tin doped Zinc oxide thin films nanoparticles with various volume concentrations of 2, 4, 6, and 8V/V% were prepared by using the sol-gel method. The optical properties were investigated by using UV-Visible spectroscope, and the value exhibits the direct allowed transition. The average of transmittance was around ~(17-23) %in visible region. The optical energy band gap was calculated with wavelength (300-900) nm for pure ZnO and Sn doped ZnO thin films which decreases with increasing concentration from 3.4 eV to 3.1 eV respectively and red shift. The real dielectric(εr) and the imaginary dielectric εiare the same behavior of the refractive index(n) the extinction coefficient (k) respectively. The optical limiting properties were studied by using an SDL laser with a wavelength of 235 nm. ZnO and doping thin films an found efficient as optic limiting and depend on the concentration of the all samples.


2019 ◽  
Vol 17 (42) ◽  
pp. 108-124
Author(s):  
Ibrahim Abdulkareem Ali

        In this study, Zinc oxide nanostructures were synthesized via a hydrothermal method by using zinc nitrate hexahydrate and sodium hydroxide as a precursor. Three different annealing temperatures were used to study their effect on ZnO NSs properties. The synthesized nanostructure was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Atomic force microscope (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). Their optical properties were studied by using UV -visible spectroscopy. The XRD analysis confirms that all ZnO nanostructures have the hexagonal wurtzite structure with average crystallite size within the range of (30.59 - 34.52) nm. The crystallite size increased due to the incensement of annealing temperature. FESEM analysis indicates that ZnO has hexagonal shape of cylindrical pores, plate-like nanocrystals and Nanorods. AFM analysis shows that the average surface roughness of ZnO Nanostructures increases from 3.96 to 19.1 nm with the increase of annealing temperature. The FTIR peaks indicate successful preparation of ZnO Nanostructures. The FTIR method was used to analyses the chemical bonds which conformed the present of the Zn-O group in the region between (400-500) cm-1. The UV-visible showed a red shift in the absorption spectra related to the shift in the energy gap related to increase in the particle size.  the band gap energy has been calculated from the optical absorption spectra. The annealing process has been fond more effective on the value of energy gap. As the annealing temperature increases, the value of energy gap, increases as well; from (3.12to 3.22) eV. The prepared Nanostructure is used for antibacterial property. It shows strong antibacterial activity against S. aureus and P.aeuruginosa bacteria by the agar disc diffusion method. The white precipitate of ZnO NSs has superior antibacterial activity on gram-positive (S. aureus) than the gram-negative (P.aeuruginosa) bacteria.


2021 ◽  
pp. 2150116
Author(s):  
WUTTICHAI SINORNATE ◽  
HIDENORI MIMURA ◽  
WISANU PECHARAPA

In this work, morphological and physical properties of pyramid-like ZnO nanostructures fabricated on Sb-doped ZnO seeding films annealed under different atmospheres are extensively studied. The Sb-doped ZnO seeding films were first prepared by sol–gel spin coating technique onto glass substrate then annealed in nitrogen, air and argon followed by low-temperature hydrothermal process for ZnO nanostructures fabrication. The morphological results exhibit the growth of pyramid-like ZnO nanostructure with increasing density of the ZnO nanostructures. The crystal structure shows pyramid-like ZnO wurtzite hexagonal growth along the c-axis without any impurity phase. The growth of pyramid-like ZnO nanostructures is due to the high growth rate of (002) plane. Photoluminescence spectra exhibit the near-band-edge of all samples while the red emission appears in ZnO nanostructures after the hydrothermal process due to the imperfection in the crystal. The reflectance of ZnO nanostructures covers the visible region with the absorption edge of 375[Formula: see text]nm. The calculation shows the relevant energy band gaps in the range of 3.26–3.28[Formula: see text]eV. The difference in hydrothermally grown ZnO nanostructures is significantly affected by different annealing atmospheres.


2019 ◽  
Vol 294 ◽  
pp. 36-41
Author(s):  
Rolen Brian P. Rivera ◽  
Melchor J. Potestas ◽  
Ma. Reina Suzette B. Madamba ◽  
Rey Y. Capangpangan ◽  
Bernabe L. Linog ◽  
...  

We report on antibacterial activities of Zinc oxide (ZnO) with different structures. Fast furrier transform infrared spectroscopy ZnO nanostructures showed peaks in the range between 450–600 cm-1 indicating the successful growth through the presence of Zn-O stretching. On the other hand, impurities such as zinc complexes might be present due to the appearance of peaks at 1110 cm-1, 1390 cm-1 and 1506 cm-1. Furthermore, SEM images revealed that nanorods and sea-urchin like nanostructures are present in the produced ZnO nanostructures. Nanorods exhibit a better antibacterial response than the sea-urchin like structure. The change in structural morphology along with its purity has greatly influenced the area of bacterial inhibition zone during antibacterial testing.


2011 ◽  
Vol 364 ◽  
pp. 45-49 ◽  
Author(s):  
Azlinda Ab Azlinda ◽  
Zuraida Khusaimi ◽  
Saifollah Abdullah ◽  
Mohamad Rusop

Zinc oxide (ZnO) nanostructures prepared by immersion method were successfully grown on gold-seeded silicon substrate using Zinc nitrate hexahydrate (Zn (NO3)2.6H2O) as a precursor, separately stabilized with non-toxic urea (CH4N2O) and hexamethylene tetraamine (HMTA). The effect of changing the stabilizer of ZnO solution on the crystal structure, morphology and photoluminescence properties of the resultant ZnO is investigated. X-ray diffraction of the synthesized ZnO shows hexagonal zincite structure. The morphology of the ZnO was characterized using Field Emission Scanning Electron Microscope (FESEM). The growth of ZnO using urea as stabilizer shows clusters of ZnO nanoflower with serrated broad petals were interestingly formed. ZnO in HMTA showed growth of nanorods. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors. The formation of ZnO nanostructures is found to be significantly affected by the stabilizer.


2010 ◽  
Vol 168-170 ◽  
pp. 2348-2351
Author(s):  
Lazaro De Jesus Dominguez Gallegos ◽  
Angélica Silvestre López Rodríguez ◽  
Pio Sifuentes Gallardo ◽  
Miguel Angel Hernández Rivera ◽  
María Guadalupe Garnica Romo ◽  
...  

Indium stannate (InSnO3) films doping with small amounts of copper are made highly useful as architectural window coatings. Indium-tin-oxide (ITO) has attracted intense interest due to some of its unique characteristics; it has high optical transmittance in the visible region, low electric resistivity, and chemical stability. Therefore, ITO thin films have been found to play an important role in opto-electronic applications. In this work, uniform and transparent ITO films were deposited onto glass substrates using a sol-gel process. The initial sols were prepared by mixing solutions of indium chloride prepared in anhydrous ethanol with tin chloride and mechanically stirring and refluxed 2 hours and aged 2 week, the resultant mixture until a clear and sticky coating sol was obtained. The glass substrates were spin-coated and annealed at 500 °C. Because annealing conditions affect the microstructures, the properties of the resultant ITO films can be controlled. The optical transmittance of 200 nm thick ITO film was more than 80% in the visible region. The surface morphology examined by SEM appears to be uniform over large surface areas. The structural, microstructural and optical properties of the coatings and powders made from the sols were extensively characterized by using XRD, AFM and spectrophotometer techniques


2013 ◽  
Vol 802 ◽  
pp. 124-128 ◽  
Author(s):  
Krisana Chongsri ◽  
Siriwattana Aunpang ◽  
Wicharn Techitdheera ◽  
Wisanu Pecharapa

In this work, we report the preparation of Cu-doped ZnOthin films by sol-gel method based on zinc acetate dihydrate (CH3COO)2Zn·2H2O, Copper acetate dihydrate Cu3(CH3COO)2·H2O) and diethanolamine (HN(CH2OH)2, DEA). The precursor solution was prepared at various Cu composition ranging from 2-20 wt%. All films were spin-coated on borosilicate substrates for several coating repetition followed by annealing process at 550 °C for 4 h in an ambient air. The structural properties of the films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD results indicate the domination of hexagonal wurtzite structure of ZnO with noticeable alternation in the XRD peak intensity upon Cu doping content. SEM results revealed the grain size shape and surface morphologies of as-prepared samples. Crucial optical properties of as-prepared films were scrutinized from their UV-Vis transmission spectra. The films are highly transparent in the visible region with more than 90 % transparency within 380 nm to 800 nm. Their corresponding band gaps indicate significant red shift with increasing Cu doping content. Overall results suggest that Cu additive play a vital role on relevant optical properties of ZnO that can be adjusted to meet the requirement for practical optoelectronics applications.


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