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Associate Professor School of Electrical & Electronic Engineering Nanyang Technological University Tel: 65-6790-5369 Fax: 65-6793-3318 Email: exwsun@ntu.edu.sg |
NEWS
(12) Xiao Wei SUN was awarded of Fellow of
the Institute of Physics (IoP) – Sept 2009.
(11) Congratulations to Yoga for winning the
IEEE LEOS Graduate Student Fellowship 2008! This is the first time of winning
such an award by Singapore institutions.
The IEEE LEOS established the Graduate Student Fellowship Program in 1999 to provide Graduate Fellowships to outstanding LEOS student members pursuing graduate education within the LEOS field of interest (electro-optics, lasers, photonics, optics, or closely related fields). Up to twelve Fellowships will be awarded each year, based on the student membership in each of the main geographical regions: Americas-Europe/Mid-East/Africa-Asia/Pacific. A complimentary conference registration and a travel grant covering travel and lodging expenses will be provided to the recipient attend the LEOS Annual Meeting for the award presentation.
(10) Congratulations to Yoga for winning the
2008 Singapore Millennium Foundation Fellowship!
(9) Our paper on using low temperature ZnO
nanorods for making electronic papers was published in Nano Lett.
We report an
electrochromic (EC) display using a viologen-modified ZnO nanowire array as the
EC electrode. The ZnO nanowire array was grown directly on an indium tin oxide
(ITO) glass by a low temperature aqueous thermal decomposition method and then
modified with viologen molecules. The ZnO nanowire electrochromic device shows
fast switching time (170 and 142 ms for coloration and bleaching respectively
for a 1 cm2 cell), high coloration efficiency (196 C−1
cm2) and good stability. The improved performance of the ZnO
nanowires EC device can be attributed to the large surface area and high
crystalline and good electron transport properties of the ZnO nanowire array.
(8) Congratulations to Yang Yi to obtain the
2007 Chinese Government Award for Outstanding Self-Financed Student Abroad.
(7) Our paper on a UV (342 nm) emitting
ZnO-NPB heterojunction LED was published in Nano Lett.
An
inorganic/organic heterostructure light-emitting diode consisting of the
hole-transporting layer N,N′-di(naphth-2-yl)-N,N′-diphenylbenzidine
(NPB) and n-type ZnO nanorods fabricated by hydrothermal decomposition is
reported. Poly(methyl methacrylate) was used to form a smooth surface on top of
ZnO nanorod array with ZnO nanorod tops exposed for subsequent NPB deposition.
An unusual ultraviolet emission at 342 nm was observed in the
electroluminescence spectrum. Compared to band gap energy of ZnO (3.37 eV), the
excitonic emission is blue-shifted and broadened. The mechanism of the blue
shift is discussed in terms of the energy band diagram of the heterostructure.
(6) Congratulations to Yoga for our first
paper accepted by PRL
In this paper,
we designed an elegant experiment employing a multiple quantum well-like
structure consisting of a few repeated host and guest layers (Figure 1 left),
and discovered a new long range quenching mechanism involving a Förster-like dipole-dipole
interaction by varying the host thickness. Our quantitative analysis shows that
the efficiency as a function of host layer thickness follows the
characteristics of the long range Förster
process (Figure 1 right). The long range Förster process is found to be the dominant quenching mechanism
and determined by the overlap between the emission and absorption spectra of
the guest molecules. Based on our finding, it is possible to eliminate
concentration quenching by minimizing the emission and absorption spectra
overlap of the guest molecules, providing guidance for chemical synthesis.
Moreover, according to our finding, it is possible to develop highly efficient
OLED that do not rely on the host-guest system, hence a much more simplified
and controllable fabrication process.
(5) Congratulations to Yanjun to obtain the
2006 Chinese Government Award for Outstanding Self-Financed Student Abroad.
(4) Congratulations to Swee Tiam for winning
a Best Paper Award in
(3) Our paper appears on APL cover (
(2) Our research on field emission from ZnO
is highlighted by SPIE Newsroom, May 2006.
(1) Our work on ZnO nanocomb glucose
biosensor is reported by Nanowerk, http://www.nanowerk.com/spotlight/spotid=614.php,
3 July 2006.