Effect of Surface Defects on Green Luminescence from ZnO Nanoparticles

2011 ◽  
Author(s):  
Surender Kumar ◽  
P. D. Sahare ◽  
S. K. Tripathi ◽  
Keya Dharamvir ◽  
Ranjan Kumar ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects ◽  
Green Luminescence ◽  
Effect Of Surface

Green luminescence originates from surface defects in ZnO nanoparticles

2006 ◽  
Vol 35 (1) ◽  
pp. 199-202 ◽  
Author(s):  
Z.G. Wang ◽  
X.T. Zu ◽  
S. Zhu ◽  
L.M. Wang
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects ◽  
Green Luminescence

Effect of surface defects on the visible emission from ZnO nanoparticles

2007 ◽  
Vol 22 (9) ◽  
pp. 2404-2409 ◽  
Author(s):  
Harish Kumar Yadav ◽  
K. Sreenivas ◽  
Vinay Gupta ◽  
S.P. Singh ◽  
R.S. Katiyar
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects ◽  
Hexagonal Wurtzite Structure ◽  
Liquid Nitrogen Temperature ◽  
Intermediate Compound ◽  
Band Edge Emission ◽  
Zinc Hydroxide ◽  
Hydroxyl Groups ◽  
Green Luminescence ◽  
Zno Crystal

The luminescent property of ZnO nanoparticles prepared using the wet chemical method has been investigated. The ZnO nanoparticles in the range 5–10 nm exhibit hexagonal Wurtzite structure, and the photoluminescence (PL) spectrum at room temperature shows a broad visible luminescence band and insignificant near-bandgap emission. The broad green luminescence is dominant at both room and boiled off liquid-nitrogen temperature, while the ultraviolet band edge emission is strongly quenched. The prepared ZnO nanoparticles have residual intermediate compound on the surface in the form of an acetate group, which acts as defect centers for the emission of green luminescence. A trace amount of zinc hydroxide is observed in one of the samples and is found to further enhance the intensity of the green luminescence. Raman scattering studies on nanoparticles indicate that the acetate/hydroxyl groups are loosely bound on the surface and are not present in the interior of the ZnO crystal structure

ZnO Nanoparticles, Nanorods, Hexagonal Plates and Nanosheets Produced by Polyol Route and the Effect of Surface Passivation by Acetate Molecules on Optical Properties

2019 ◽  
Vol 48 (10) ◽  
pp. 6437-6445
Author(s):  
Eduardo F. Barbosa ◽  
Jaqueline A. Coelho ◽  
Edna R. Spada ◽  
Daniel R. B. Amorim ◽  
Livia M. C. Souza ◽  
...  
Keyword(s):  
Optical Properties ◽  
Zno Nanoparticles ◽  
Surface Passivation ◽  
Effect Of Surface

Effect of surface defects on the fatigue behavior of a cast TiAl alloy.

2000 ◽  
Vol 646 ◽  
Author(s):  
M. Nazmy ◽  
M. Staubli ◽  
G. Onofrio ◽  
V. Lupinc
Keyword(s):  
Tial Alloy ◽  
High Cycle Fatigue ◽  
Surface Defects ◽  
Fatigue Behavior ◽  
Impact Resistance ◽  
Economic Life ◽  
Crack Advance ◽  
Crack Growth Behavior ◽  
Engine Components ◽  
Effect Of Surface

ABSTRACTThe effect of surface defects on the performance of TiAl-base alloys is an issue of importance in contemplating their application into engine components. Due to the relatively low ductility and low impact resistance of gamma alloys the validation of models for estimating economic life and for safe-life approaches employed for components becomes of great importance. Surface defects can be attributed to various sources during the manufacturing or handling of the components. In fact, little is known about the detrimental effects of surface defects on gamma alloys. In the present study, the effect of artificially introduced surface defects, on the high cycle fatigue behavior of the Ti-47Al-2W-0.5Si, will be investigated and correlated with the crack growth behavior at 700°C. The results are reported in the form of the Kitagawa diagram in which the safe and unsafe zones for crack advance and fracture are defined.

scholarly journals Precise Control of Surface Oxygen Vacancies in ZnO Nanoparticles for Extremely High Acetone Sensing Response

2021 ◽  
Author(s):  
Jihyun Lee ◽  
Youngmoon Choi ◽  
Byoung Joon Park ◽  
Jeong Woo Han ◽  
Hyun-Sook Lee ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Oxygen Vacancies ◽  
Surface Defects ◽  
High Sensitivity ◽  
Fast Response ◽  
Oxide Semiconductor ◽  
Surface Oxygen ◽  
Zno Nps ◽  
Precise Control ◽  
Optimal Surface

Abstract ZnO has been studied intensely for chemical sensors due to its high sensitivity and fast response. Here, we present a simple approach to precisely control oxygen vacancy contents to provide significantly enhanced acetone sensing performance of commercial ZnO nanopowders. A combination of H2O2 treatment and thermal annealing produces optimal surface defects with oxygen vacancies on the ZnO nanoparticles (NPs). The highest response of ~27,562 was achieved for 10 ppm acetone in 0.125 M H2O2 treated/annealed ZnO NPs at the optimal working temperature of 400 ℃, which is significantly higher than that of reported so far in various acetone sensors based on metal-oxide-semiconductor (MOS). Furthermore, first-principles calculations indicate that pre-adsorbed O formed on the surface of H2O2-treated ZnO NPs can provide a favorable adsorption energy, especially for acetone detection, due to strong bidentate bonding between carbonyl C atom of acetone molecules and pre-adsorbed O on the ZnO surface. Our study demonstrates that controlling surface oxygen vacancies by H2O2 treatment and re-annealing at optimal temperature is an effective method to improve the sensing properties of commercial MOS materials.

Photoreactivity of ZnO nanoparticles in visible light: Effect of surface states on electron transfer reaction

2009 ◽  
Vol 105 (7) ◽  
pp. 074308 ◽  
Author(s):  
Sunandan Baruah ◽  
Sudarson Sekhar Sinha ◽  
Barnali Ghosh ◽  
Samir Kumar Pal ◽  
A. K. Raychaudhuri ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Zno Nanoparticles ◽  
Transfer Reaction ◽  
Surface States ◽  
Electron Transfer Reaction ◽  
Light Effect ◽  
Effect Of Surface
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