Browsing by Subject "Silicon quantum dots"

Now showing 1 - 3 of 3

Open Access
Fluorescent Si QD decoration onto a flexible polymeric electrospun nanofibrous mat for the colorimetric sensing of TNT
(Royal Society of Chemistry, 2017) Arslan, O.; Aytac Z.; Uyar, Tamer
UV range light was used for the facile, effective and large-scale synthesis of visible light emitting, surface-protected silicon quantum dots (Si QDs) starting from an amine-functionalized alkoxy silane precursor. Within mild and easy hydrolysis/condensation environments, the use of an amine-functionalized precursor together with a reducing agent resulted in a bright visible green light that could be used for fluorescent analytical detection systems. Visible light emitting Si QDs were investigated and it was found that their emission character depends on the illumination time, hydrolysis/condensation conditions and pretreatments for the silane coupling agents. A Nylon 6,6 electrospun nanofibrous mat was selected as a substrate for decoration by the Si QDs in order to fabricate a flexible and free-standing polymeric nanofibrous mat posessing a visible light emitting character so that it could act as a visible colorimetric sensor. The visible light emitting Si QDs were decorated onto the Nylon 6,6 nanofibrous mats via covering the surfaces as a ‘nanodress’ by a simple impregnation/dip-coating and heat-curing methods. The analytical results revealed that the Si QDs decorated flexible polymeric nanofibrous mats could be utilized for colorimetric trinitrotoluene (TNT) detection in low concentrations.
Open Access
Multifunctional electrospun polymeric nanofibrous mats for catalytic reduction, photocatalysis and sensing
(Royal Society of Chemistry, 2017) Arslan, O.; Uyar, Tamer
Fabrication and decoration of flexible Nylon 6,6 polymeric nanofibrous mats for production of multifunctional electrospun material was accomplished via visible light-emitting surface-protected silicon quantum dots (Si QD), ZnO nanoparticles (ZnO NP) and Pd nanocubes (Pd NC). UV-range light was utilized for Si QD production and, after hydrolysis/condensation together with nucleation and growth reactions, amine-modified, fluorescent Si QD were obtained. Additionally, available molecular groups on the Si QD coated onto the polymeric nanofibrous mats provided further attachment of metal oxide and metal NP for various catalytic purposes. Analytical investigations showed that visible-light emission could be maintained on the Nylon 6,6 mats for trinitrotoluene (TNT) sensing. Also, due to consecutive NP decoration, multifunctional, polymeric, flexible nanofibrous mats were obtained. Experiments revealed that fabricated multifunctional mats could reduce molecules such as paranitrophenol effectively or decompose waste dyes such as methylene blue via photocatalytic experiments, and sense the pollutant TNT in aqueous solutions as an all-in-one concept.
Open Access
Strongly Scale-Dependent Charge Transport From Interconnections of Silicon Quantum Dots and Nanowires
(Cambridge University Press, 2017) Ilday, S.
We present the first characterization of strongly scale-dependent charge transport of a unique, hierarchical complex topology: an interconnected random network of silicon quantum dots (QDs) and nanowires. We show that this specific topology has different charge transport characteristics on the nanoscale and the microscale: photogenerated charge carriers tend to be confined inside the QDs and externally injected charge carriers flow preferably along the nanowires. The former enables expression of quantum confinement properties, and the latter mainly contributes to the good electrical conduction on the microscale. Our findings strongly suggest that this multifunctionality can be controlled and used in photovoltaic device applications.