The influence of annealing temperature on the structure, morphologies and optical properties of ZnO nanoparticles

Hammad, Talaat M.; Salem, Jamil K.; Harrison, Roger G.

doi:10.1016/j.spmi.2009.11.007

Cited by 60 publications

(27 citation statements)

References 31 publications

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“…Different synthesis methods, such as solid-state reaction [18], coprecipitation [19][20][21], sol-gel [22][23][24], hydrothermal [25][26][27], pyrosol [28,29], microemulsion [30][31][32], combustion [13], and electrochemical methods [33,34] have been used in order to obtain the europium-doped zinc oxide nanoparticles. The precipitation/coprecipitation method, as compared to other chemical or physical methods, is an inexpensive method which allows the synthesis of a wide range of nanoparticles with different and controlled sizes and shapes [19,20,[35][36][37].…”

Section: Introductionmentioning

confidence: 99%

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A valence states approach for luminescence enhancement by low dopant concentration in Eu-doped ZnO nanoparticles

et al. 2015

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The paper presents a simple, reproducible, controllable, and direct wet chemical synthesis method for Zn 1-x Eu x O nanoparticles. The full understanding of decomposition mechanism of the as-obtained oxalate precipitate was achieved based on the thermal analysis correlated with the evolved gas analysis and FTIR spectroscopy. The structure, morphology, and optical luminescent properties of the Zn 1-x Eu x O nanoparticles have been investigated by X-ray diffraction, Raman spectroscopy, HRTEM, SAED, XPS, and PL. The XRD studies reveal the formation of a hexagonal wurtzite-type structure. The presence of Eu 2 O 3 cubic structure can be observed up to 0.5 mol% Eu, suggesting that the solubility of the divalent or trivalent Eu into the ZnO lattice is limited. The formation of Eu 2 O 3 secondary phase at higher Eu concentration is sustained by Raman spectroscopy and XPS, as well. The TEM investigations of the Eu-doped ZnO samples illustrate the presence of aggregates with different shapes and dimensions formed by agglomerated spherical and polyhedral nanoparticles with sizes ranging from 20 to 120 nm. The effect of europium concentration on the structural and morphological characteristics, as well as on the luminescent properties was studied with special emphasis on the europium chemical states-Eu 2? and Eu 3? . The PL measurements sustain the presence of both divalent and trivalent europium ions into the ZnO host lattice and, at the same time, an increase of its defects density induced by the dopant presence.

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Section: Introductionmentioning

confidence: 99%

“…The precipitation/coprecipitation method, as compared to other chemical or physical methods, is an inexpensive method which allows the synthesis of a wide range of nanoparticles with different and controlled sizes and shapes [19,20,[35][36][37].…”

Section: Introductionmentioning

confidence: 99%

A valence states approach for luminescence enhancement by low dopant concentration in Eu-doped ZnO nanoparticles

et al. 2015

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“…The emission at around 380-400 nm is the characteristic near-band-edge emission due to the recombination of free photogenerated electrons and holes [44] and the other one is a deep-level emission mostly in the green region (471 nm), which is produced by the transition of excited optical centers from the deep level to the valence level, such deep-level emission being usually accompanied by the presence of structural defects [19,45]. The red-shift of UV emission was observed from 390 to 412 nm due to the increase in size of the particles [46,47]. It is well known that the photo-generated electronhole pairs recombine, the photocatalytic activity would be decreased, higher the PL intensity lower the life time for photogeneration of electron hole pairs [48].…”

Section: Photoluminescence Of Zno Nanostructuresmentioning

confidence: 99%

Template free large scale synthesis of multi-shaped ZnO nanostructures for optical, photocatalytical and antibacterial properties

Kadam

Dhabbe

Kokate

et al. 2015

J Mater Sci: Mater Electron

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In this article, ZnO nanostructures with diverse morphologies have been synthesized via a simple, rapid and cost effective solid state thermal decomposition method. The as-synthesized ZnO nanostructures were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM), UV-Vis. diffuse reflectance spectra (UV-Vis-DRS) and photoluminescence (PL). The XRD patterns and HR-TEM image indicated a hexagonal wurtzite structure of ZnO. The SEM images of ZnO samples show the different morphologies such as nanowire, nanorods, spherical and irregular microsphere at different calcination temperatures. Room temperature PL spectra of the samples exhibited characteristics blue and green emission bands in accordance with calcination temperature. Moreover, photocatalytic as well as antimicrobial activities were evaluated using ZnO synthesized at different calcination temperatures. The effects of calcination temperature, catalyst loading and pH on the photodegradation efficiency were systematically studied. A highest (99 %) photocatalytic activity of ZnO nanorods towards the Acid Green 25 (AG-25) was achieved within 35 min at optimal conditions under UV light. As-synthesized ZnO nanorods are found to be more efficient than TiO 2 (P25) towards the degradation of AG-25. It was found that the antimicrobial activity of ZnO nanorods (13 mm) obtained at 300°C showed significantly higher inhibition efficiencies than the other samples. The mineralization of AG-25 was confirmed from a reduction of 85 % the chemical oxygen demand within 35 min. In addition, ZnO nanorods could be easily reusable up to four runs without changing its photocatalytic activity.

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“…Physical and wet chemical techniques have been reported in many literatures. Physical techniques includes radio frequency magnetron sputtering (RFMS) [8], laser deposition [9], molecular beam epitaxy (MBE) [10,11]. On the other hand, chemical techniques include coprecipitation [12], hydrothermal [13], sol gel [14] and others.…”

Section: Introductionmentioning

confidence: 99%

“…Wet chemical method has been chosen because of simplicity, economical consideration and highly efficient of the process [15]. In addition, the capability to control the particle size and morphology is more available over other methods to optimize the properties of NPs by adjusting the influence of parameters such as solvent [16], metal source precursor salts (nitrate, acetate, chlorate, sulfate) [17], molar ratio [18], pH value [19], calcination temperature [10], aging time [20], the presence of additives surfactant or polymer [21] and any other metal doping [22]. Until now, hydrothermal technique of zinc salt such as (Zn(CH 3 COO) 2.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of the performance of dye-sensitized solar cells using sensitized zinc oxide nanoparticles by rhodamine B dye

et al. 2019

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I N THE PRESENT work, ZnO nanoparticles were synthesized via a simple wet chemical (hydrothermal) technique using zinc acetate dihydrate (Zn(CH 3 COO) 2. 2H 2 O) as a row material dissolved into absolute methanol and aqueous NaOH as precipitation agent. The X-ray diffractometer (XRD) patterns showed a standard hexagonal wurtzite structure of ZnO NPs with average particle size of about 28±2 nm. High resolution-transmission electron microscopy (HR-TEM) micrograph of ZnO NPs showed semi-spherical particles with an average size of about 25.3±6 nm, which agreed well with the XRD results. UV-Vis spectrum of the ZnO NPs revealed the highest absorption band at 366.4 nm and the optical energy gap (E g ) was about 3.12 eV. The Photoluminescence spectrophotometer (PL) spectrum emission illustrated lower UV emission than the visible emission. This indicated to the high defect density in ZnO sample. The effect of concentration of cost-effective Rhodamine B dye on the performance of dye-sensitized solar cells) DSSCs) based on ZnO NPs has been studied. The best performance among the five concentrations was 0.7 mM. The photon to electric energy conversion efficiency of the DSSCs has been found to increase by eight times from 0.07 to 0.58 %. Transient open-circuit voltage decay (TOCVD) method has been used to investigate the electron lifetime (τn) and the electron recombination velocity (K rec ) in DSSCs, by using the double exponential function. The results revealed that the Rhodamine B dye can be an efficient dye as a low-cost sensitizing dye for DSSCs.

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The influence of annealing temperature on the structure, morphologies and optical properties of ZnO nanoparticles

Cited by 60 publications

References 31 publications

A valence states approach for luminescence enhancement by low dopant concentration in Eu-doped ZnO nanoparticles

A valence states approach for luminescence enhancement by low dopant concentration in Eu-doped ZnO nanoparticles

Template free large scale synthesis of multi-shaped ZnO nanostructures for optical, photocatalytical and antibacterial properties

Enhancement of the performance of dye-sensitized solar cells using sensitized zinc oxide nanoparticles by rhodamine B dye

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