مجال
التميز
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تميز دراسي و بحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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Photo-induced enhanced Raman
spectroscopy for universal ultra-trace detection of explosives, pollutants
and biomolecules
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تاريخ النشر:
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14/07/2016
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موجز عن البحث:
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Surface-enhanced Raman
spectroscopy is one of the most sensitive spectroscopic techniques available,
with single-molecule detection possible on a range of noble-metal substrates.
It is widely used to detect molecules that have a strong Raman response at very
low concentrations. Here we present photo-induced-enhanced Raman
spectroscopy, where the combination of plasmonic nanoparticles with a
photo-activated substrate gives rise to large signal enhancement (an order of
magnitude) for a wide range of small molecules, even those with a typically
low Raman cross-section. We show that the induced chemical enhancement is due
to increased electron density at the noble-metal nanoparticles, and
demonstrate the universality of this system with explosives, biomolecules and
organic dyes, at trace levels. Our substrates are also easy to fabricate,
self-cleaning and reusable.
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البحث (2):
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عنوان البحث:
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Sensitive and specific detection
of explosives in solution and vapour by surface-enhanced Raman spectroscopy
on silver nanocubes
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تاريخ النشر:
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12/10/2017
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Surface-enhanced Raman
spectroscopy (SERS) has been widely utilised as a sensitive analytical
technique for the detection of trace levels of organic molecules. The
detection of organic compounds in the gas phase is particularly challenging
due to the low concentration of adsorbed molecules on the surface of the SERS
substrate. This is particularly the case for explosive materials, which
typically have very low vapour pressures, limiting the use of SERS for their
identification. In this work, silver nanocubes (AgNCs) were developed as a
highly sensitive SERS substrate with very low limit-of-detection (LOD) for
explosive materials down to the femtomolar (10−15 M) range.
Unlike typical gold-based nanostructures, the AgNCs were found suitable for
the detection of both aromatic and aliphatic explosives, enabling detection
with high specificity at low concentration. SERS studies were first carried
out using a model analyte, Rhodamine-6G (Rh-6G), as a probe molecule. The
SERS enhancement factor was estimated as 8.71 × 1010 in this
case. Further studies involved femtomolar concentrations of
2,4-dinitrotoluene (DNT) and nanomolar concentrations of
1,3,5-trinitroperhydro-1,3,5-triazine (RDX), as well as vapour phase
detection of DNT.
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البحث (3):
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عنوان البحث:
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Nanoparticles
in explosives detection – the state-of-the-art and future directions
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تاريخ النشر:
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12/08/2017
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Nanoparticle-ligand systems can
be targeted to specific analytes to effect a change in the properties of the
nanoparticles. We will examine two examples in which the electromagnetic
properties of the nanoparticles (arising from their small size) are altered
by analyte binding, and can be applied as a transducer in a chemical sensing
system for explosive analytes. The first property reviewed is the surface
plasmon resonance (SPR) band of colloidal gold nanoparticles (AuNPs), and the
second, the fluorescence of colloidal semiconductors (quantum dots – QDs).
Sensors based on these
nanoparticle properties have the potential to detect picomolar or lower
concentrations of explosive analytes, and can operate for both solution phase
and gas phase detection [1, 2, 3]. In
addition, measurement of the signal produced by the nanoparticle transducer
uses standard scientific instrumentation, making it easier to build complete
detection systems from standard components – an important consideration [4].
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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6th International Chemistry
Conference, Nanotechnology and Materials Science
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تاريخ الإنعقاد:
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10/11/2016
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مكان
الإنعقاد:
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Riyadh, KSA
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طبيعة المشاركة:
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Poster presentation
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عنوان المشاركة:
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A sensitive substrate of TiO2
(thin film)/ Au nanoparticles for detection of explosives by Surface-
enhanced Raman spectroscopy (SERS)
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ملخص المشاركة:
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In this work we demonstrate a
new SERS substrate that utilises gold nanoparticles (AuNPs) on a rutile- TiO2
substrate to achieve ultra-trace (sub picomolar) detection of explosives. A
range of high-explosives could then be detected in solution and vapour phase
at ultra-trace levels, simply and in a repeatable manner. Furthermore, the
substrates could be easily cleaned of all organic residues for reuse with no
ill effect on enhancement. A SERS substrate was fabricated by depositing gold
nanoparticles on a thin film of TiO2 followed by deposition of
analyte species. The performance of this sensor was optimize for good SERS
enhancement and rapid time response.
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المؤتمر (2):
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عنوان المؤتمر:
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NanoPhotonics and Micro/Nano Optics
International Conference – NANOP 2016
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تاريخ الإنعقاد:
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09/12/2016
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مكان
الإنعقاد:
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Paris, France
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طبيعة المشاركة:
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Poster presentation
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عنوان المشاركة:
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Photo-Induced Enhanced Raman
spectroscopy (PIERS) for detection of ultra-trace levels of Explosives
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ملخص المشاركة:
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Here we present an enhancement method
titled “Photo-induced-enhanced Raman spectroscopy”(PIERS), where the
combination of plasmonic nanoparticles with a photo-activated substrate gives
rise to large signal enhancement for a wide range of small molecules. We show
that the induced chemical enhancement is due to increased electron density at
the noble-metal nanoparticles, and demonstrate the universality of this
system with explosives, bio-molecules and organic dyes, at trace levels. Our
substrates are also easy to fabricate, self – cleaning and reusable.
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المؤتمر (3):
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عنوان المؤتمر:
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2nd Saudi International Conference of Forensic Medicine and Sciences
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تاريخ الإنعقاد:
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12-14/03/2017
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مكان
الإنعقاد:
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Riyadh, KSA
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طبيعة المشاركة:
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Paper presentation
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عنوان المشاركة:
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High sensitive substrate of
silver nanocubes (AgNCs) for detection of trace levels of explosives by
Surface Enhanced Raman spectroscopy SERS
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ملخص المشاركة:
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In this work, highly sensitive
SERS substrates with very low-limit-of-detection (LOD) of explosive materials
was reported. Silver nanocubes (AgNCs) (with some nanorods) were prepared
using polyol method where of Ag+ to Ag0 was reduced by
ethylene glycol in the presence of poly (vinyl pyrrolidone) (PVP) and a trace
amount of Na2S. AgNCs were characterized by UV-Vis (surface plasmon resonance
was seen at a λ=480 nm), scanning electron microscopy and X-ray diffraction.
AgNCs were examined as SERS substrate using Rhodamine-6G and used for
detection of two selected explosives 2, 4-dinitrotoluene (DNT), and 1, 3,
5-trinitroperhydro-1, 3, 5-triazine (RDX). This provided high sensitivity and
selectivity detection with limit of detection lower than femto molar. Laser
excitation was 633 nm with laser power of 1.9 eV ( 7.4 mW). The detection
enhancement factor that was achieved is ≈ 6.4×108.
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