The origin of luminescence from di[4-(4-diphenylaminophenyl)phenyl]sulfone (DAPSF), a blue light emitter: an X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) study

2016 ◽  
Vol 18 (9) ◽  
pp. 6406-6410 ◽  
Author(s):  
Duo Zhang ◽  
Hui Zhang ◽  
Xiaohong Zhang ◽  
Tsun-Kong Sham ◽  
Yongfeng Hu ◽  
...  
Keyword(s):  
Blue Light ◽  
Luminescence Band ◽  
Functional Group ◽  
Edge Structure ◽  
X Ray ◽  
Light Emitter ◽  
Phenyl Sulfone ◽  
Optical Luminescence ◽  
Blue Luminescence Band ◽  
X Ray Absorption

The blue luminescence band of DAPSF is primarily associated with the sulfur functional group.

Soft X-ray excited colour-centre luminescence and XANES studies of calcium oxide

2007 ◽  
Vol 85 (10) ◽  
pp. 853-858 ◽  
Author(s):  
JY Peter Ko ◽  
Franziskus Heigl ◽  
Yun Mui Yiu ◽  
Xing-Tai Zhou ◽  
Tom Regier ◽  
...  
Keyword(s):  
Calcium Oxide ◽  
Density Functional ◽  
X Rays ◽  
Colour Centre ◽  
Time Resolved ◽  
Edge Structure ◽  
Colour Centres ◽  
X Ray ◽  
Optical Luminescence ◽  
X Ray Absorption

In this study, we show that colour centres can be produced by irradiating calcium oxide with soft X-rays from a synchrotron radiation source. Using the X-ray excited optical luminescence (XEOL) technique, two colour centres, F-centre, and F+-centre can be identified. These colour centres emit photons at characteristic wavelengths. In addition, by performing time-resolved XEOL (TRXEOL), we are able to reveal timing and decay characteristics of the colour centres. We also present X-ray absorption near-edge structure (XANES) spectra collected across oxygen K-edge, calcium L3,2-edge, and calcium K-edge. Experimental results are compared with density functional theory (DFT) calculations.Key words: calcium oxide, colour centre, synchrotron, X-ray excited optical luminescence, X-ray absorption near-edge structure.

Origin of luminescence from ZnO/CdS core/shell nanowire arrays

Nanoscale ◽  
2014 ◽  
Vol 6 (16) ◽  
pp. 9783-9790 ◽  
Author(s):  
Zhiqiang Wang ◽  
Jian Wang ◽  
Tsun-Kong Sham ◽  
Shaoguang Yang
Keyword(s):  
Optical Properties ◽  
Chemical Imaging ◽  
Nanowire Arrays ◽  
Nano Composites ◽  
Core Shell ◽  
Edge Structure ◽  
X Ray ◽  
Optical Luminescence ◽  
Scanning Transmission ◽  
X Ray Absorption

Chemical imaging, electronic structure and optical properties of ZnO/CdS nano-composites have been investigated using scanning transmission X-ray microscopy (STXM), X-ray absorption near-edge structure (XANES) and X-ray excited optical luminescence (XEOL) spectroscopy.

Cathodoluminescence, X-ray excited optical luminescence, and X-ray absorption near-edge structure studies of ZnO nanostructures

2012 ◽  
Vol 90 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Olga Lobacheva ◽  
Patricia L. Corcoran ◽  
Michael W. Murphy ◽  
Jun Young Peter Ko ◽  
Tsun-Kong Sham
Keyword(s):  
Gas Flow ◽  
Branching Ratio ◽  
Optical Emission ◽  
Zno Nanostructures ◽  
Edge Structure ◽  
X Ray ◽  
Synthesis Parameters ◽  
Optical Luminescence ◽  
Carrier Gas Flow ◽  
X Ray Absorption

ZnO nanostructures of various morphologies and crystallinities were fabricated by thermal evaporation from Zn powder in a tube furnace in the presence of oxygen. It was found that the morphology of ZnO nanostructures was affected by synthesis parameters, such as growth temperature, carrier gas flow, and the presence of catalyst on the surface of the substrate. Representative ZnO nanostructures were studied by X-ray excited optical luminescence (XEOL) and cathodoluminescence (CL) methods. The luminescence from these samples exhibits a morphology dependence of the branching ratio of the near band gap (NBG) emission in the UV and defect emission in the green (GE). The appearance of the optical emission also depends on the excitation method. X-ray absorption near-edge structures (XANES) at the O K-edge and Zn L-edge are also presented and their implications discussed.

Morphology-dependent luminescence from ZnO nanostructures — An X-ray excited optical luminescence study at the Zn K-edge

2009 ◽  
Vol 87 (9) ◽  
pp. 1255-1260 ◽  
Author(s):  
Olga Lobacheva ◽  
Michael W. Murphy ◽  
Jun Young Peter Ko ◽  
Tsun-Kong Sham
Keyword(s):  
Gas Flow ◽  
Thermal Evaporation ◽  
Growth Conditions ◽  
Zno Nanostructures ◽  
Edge Structure ◽  
X Ray ◽  
Si Substrates ◽  
Optical Luminescence ◽  
Carrier Gas Flow ◽  
X Ray Absorption

ZnO nanostructures have been synthesized by thermal evaporation on Si substrates. It is found that the morphologies of the nanostructures are governed by growth conditions such as temperature, carrier-gas flow rate, and the nature of the substrate (with and without a catalyst). We report X-ray excited optical luminescence from ZnO nanostructures of distinctly different morphologies in the energy and time domain using excitation photon energies across the Zn K-edge. X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) study has clearly shown the morphology dependence of the ZnO optical properties. A correlation of luminescence with morphology, size, and crystallinity emerges.

2D XANES-XEOL mapping: observation of enhanced band gap emission from ZnO nanowire arrays

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6531-6536 ◽  
Author(s):  
Zhiqiang Wang ◽  
Xiaoxuan Guo ◽  
Tsun-Kong Sham
Keyword(s):  
Band Gap ◽  
Nanowire Arrays ◽  
Zno Nanowire ◽  
Edge Structure ◽  
X Ray ◽  
Zno Nanowire Arrays ◽  
Optical Luminescence ◽  
Order Of Magnitude ◽  
X Ray Absorption ◽  
Mapping Observation

Using two-dimensional X-ray absorption near-edge structure-X-ray excited optical luminescence (2D XANES-XEOL) spectroscopy, it is found that the band gap emission of ZnO nanowire arrays is substantially enhancedi.e.that the intensity ratio between the band gap and defect emissions increases by more than an order of magnitude when the excitation energy is scanned across the O K-edge. Possible mechanisms are discussed.

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