Influence of point defects concentration on optical and photocatalytic properties of ZnO ceramics

2016
Authors
Marković, Smilja
Rajić, Vladimir B.

Veselinović, Ljiljana

Belošević Čavor, Jelena

Škapin, Srečo Davor

Stojadinović, Stevan
Rac, Vladislav
Lević, Steva

Mojović, Miloš
Uskoković, Dragan

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Zinc oxide is one of the most studied materials due to its wide bandgap (3.37 eV) and large exciton binding energy (60 meV) which enables application in electronics, optoelectronics and spintronics. In the forms of single crystal and thin-film ZnO are used as UV and blue light emitter, while sintered ZnO-based ceramics are important as varistors, thermistors or semiconductors. It has been found that point defects in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Neutral oxygen vacancies are considered to be a major component of the defect structure of ZnO. Thus, correlation of the oxygen vacancies concentration with band gap energy of ZnO product is important to its application in optoelectronic devices. In this study we investigated the influence of point defects concentration in ZnO crystal structure on its optical and photocatalytic properties. We analyzed ZnO powders prepared by different techniques: (a) microwave processing of precipitate... and (b) hydrothermal processing, which yield different ordered crystal structure. To increase a concentration of the point defects in the crystal structure, the powders were sintered in air atmosphere by heating rate of 10 °/min up to 1100 °C, with dwell time of 1 h. The crystal structure, average crystallite size and phase purity of the ZnO ceramics were determined by X-ray diffraction and Raman spectroscopy. The optical properties, in particular, absorption capacity and bang gap energy, were studied using UV–Vis diffuse reflectance spectroscopy. To reveal the role of microstructures and point defects in ZnO crystal lattice, which are receptive for luminescence and photocatalytic activity of this functional oxide, photoluminescence (PL), photoluminescence excitation (PLE) and EPR spectra were analyzed. The influence of point defects concentration in the ZnO crystal structure on photocatalytic properties was examined via decolorization of methylene blue under direct sunlight irradiation. Correlation between amount of the point defects, absorption capacity and photocatalytic efficiency were established. In order to clarify the experimental results ab initio calculations based on density functional theory (DFT) were performed.
Keywords:
ZnO / ceramics / optical properties / photocatalytic propertiesSource:
Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016, 2016, 34-34Publisher:
- Belgrade : Materials Research Society of Serbia
Projects:
TY - CONF AU - Marković, Smilja AU - Rajić, Vladimir B. AU - Veselinović, Ljiljana AU - Belošević Čavor, Jelena AU - Škapin, Srečo Davor AU - Stojadinović, Stevan AU - Rac, Vladislav AU - Lević, Steva AU - Mojović, Miloš AU - Uskoković, Dragan PY - 2016 UR - http://dais.sanu.ac.rs/123456789/902 AB - Zinc oxide is one of the most studied materials due to its wide bandgap (3.37 eV) and large exciton binding energy (60 meV) which enables application in electronics, optoelectronics and spintronics. In the forms of single crystal and thin-film ZnO are used as UV and blue light emitter, while sintered ZnO-based ceramics are important as varistors, thermistors or semiconductors. It has been found that point defects in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Neutral oxygen vacancies are considered to be a major component of the defect structure of ZnO. Thus, correlation of the oxygen vacancies concentration with band gap energy of ZnO product is important to its application in optoelectronic devices. In this study we investigated the influence of point defects concentration in ZnO crystal structure on its optical and photocatalytic properties. We analyzed ZnO powders prepared by different techniques: (a) microwave processing of precipitate and (b) hydrothermal processing, which yield different ordered crystal structure. To increase a concentration of the point defects in the crystal structure, the powders were sintered in air atmosphere by heating rate of 10 °/min up to 1100 °C, with dwell time of 1 h. The crystal structure, average crystallite size and phase purity of the ZnO ceramics were determined by X-ray diffraction and Raman spectroscopy. The optical properties, in particular, absorption capacity and bang gap energy, were studied using UV–Vis diffuse reflectance spectroscopy. To reveal the role of microstructures and point defects in ZnO crystal lattice, which are receptive for luminescence and photocatalytic activity of this functional oxide, photoluminescence (PL), photoluminescence excitation (PLE) and EPR spectra were analyzed. The influence of point defects concentration in the ZnO crystal structure on photocatalytic properties was examined via decolorization of methylene blue under direct sunlight irradiation. Correlation between amount of the point defects, absorption capacity and photocatalytic efficiency were established. In order to clarify the experimental results ab initio calculations based on density functional theory (DFT) were performed. PB - Belgrade : Materials Research Society of Serbia C3 - Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016 T1 - Influence of point defects concentration on optical and photocatalytic properties of ZnO ceramics SP - 34 EP - 34 ER -
@conference{ author = "Marković, Smilja and Rajić, Vladimir B. and Veselinović, Ljiljana and Belošević Čavor, Jelena and Škapin, Srečo Davor and Stojadinović, Stevan and Rac, Vladislav and Lević, Steva and Mojović, Miloš and Uskoković, Dragan", year = "2016", url = "http://dais.sanu.ac.rs/123456789/902", abstract = "Zinc oxide is one of the most studied materials due to its wide bandgap (3.37 eV) and large exciton binding energy (60 meV) which enables application in electronics, optoelectronics and spintronics. In the forms of single crystal and thin-film ZnO are used as UV and blue light emitter, while sintered ZnO-based ceramics are important as varistors, thermistors or semiconductors. It has been found that point defects in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Neutral oxygen vacancies are considered to be a major component of the defect structure of ZnO. Thus, correlation of the oxygen vacancies concentration with band gap energy of ZnO product is important to its application in optoelectronic devices. In this study we investigated the influence of point defects concentration in ZnO crystal structure on its optical and photocatalytic properties. We analyzed ZnO powders prepared by different techniques: (a) microwave processing of precipitate and (b) hydrothermal processing, which yield different ordered crystal structure. To increase a concentration of the point defects in the crystal structure, the powders were sintered in air atmosphere by heating rate of 10 °/min up to 1100 °C, with dwell time of 1 h. The crystal structure, average crystallite size and phase purity of the ZnO ceramics were determined by X-ray diffraction and Raman spectroscopy. The optical properties, in particular, absorption capacity and bang gap energy, were studied using UV–Vis diffuse reflectance spectroscopy. To reveal the role of microstructures and point defects in ZnO crystal lattice, which are receptive for luminescence and photocatalytic activity of this functional oxide, photoluminescence (PL), photoluminescence excitation (PLE) and EPR spectra were analyzed. The influence of point defects concentration in the ZnO crystal structure on photocatalytic properties was examined via decolorization of methylene blue under direct sunlight irradiation. Correlation between amount of the point defects, absorption capacity and photocatalytic efficiency were established. In order to clarify the experimental results ab initio calculations based on density functional theory (DFT) were performed.", publisher = "Belgrade : Materials Research Society of Serbia", journal = "Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016", title = "Influence of point defects concentration on optical and photocatalytic properties of ZnO ceramics", pages = "34-34" }
Marković S, Rajić VB, Veselinović L, Belošević Čavor J, Škapin SD, Stojadinović S, Rac V, Lević S, Mojović M, Uskoković D. Influence of point defects concentration on optical and photocatalytic properties of ZnO ceramics. Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016. 2016;:34-34
Marković, S., Rajić, V. B., Veselinović, L., Belošević Čavor, J., Škapin, S. D., Stojadinović, S., Rac, V., Lević, S., Mojović, M.,& Uskoković, D. (2016). Influence of point defects concentration on optical and photocatalytic properties of ZnO ceramics. Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016Belgrade : Materials Research Society of Serbia., null, 34-34.
Marković Smilja, Rajić Vladimir B., Veselinović Ljiljana, Belošević Čavor Jelena, Škapin Srečo Davor, Stojadinović Stevan, Rac Vladislav, Lević Steva, Mojović Miloš, Uskoković Dragan, "Influence of point defects concentration on optical and photocatalytic properties of ZnO ceramics" null (2016):34-34