Photoluminescence properties of SnO2 nanowhiskers grown by thermal evaporation

Visible light photocatalytic NOx removal with suppressed poisonous NO2 byproduct generation over simply synthesized triangular silver nanoparticles coupled with tin dioxide

The treatment or conversion of air pollutants with a low generation of secondary toxic substances has become a hot topic in indoor air pollution abatement. Herein, we used triangle-shaped Ag nanoparticles coupled with SnO2 for efficient photocatalytic NO removal. Ag triangular nanoparticles (TNPs) were synthesized by the photoreduction method and SnO2 was coupled by a simple chemical impregnation process. The photocatalytic NO removal activity results show that the modification with Ag TNPs significantly boosted the removal performance up to 3.4 times higher than pristine SnO2. The underlying roles of Ag TNPs in NO removal activity improvement are due to some advantages of Ag TNPs. Moreover, the Ag TNPs contributed photogenerated holes as the main active species toward enhancing the NO oxidation reaction. In particular, the selectivity toward green products significantly improved from 52.78% (SnO2) to 86.99% (Ag TNPs/SnO2). The formation of reactive radicals under light irradiation was also verified by DMPO spin-trapping experiments. This work provides a potential candidate for visible-light photocatalytic NO removal with low toxic byproduct generation.

Synthesis of Hierarchical SnO2 Nanowire-TiO2 Nanorod Brushes Anchored to Commercially Available FTO-coated Glass Substrates

Growth of single-crystal SnO₂ nanowires using a fluorine-doped SnO₂ (FTO) thin film as both the source and substrate is demonstrated for the first time at relatively low temperature (580 °C) which preserves the integrity of the underlying glass support and improves scalability to devices. Furthermore, a microwave hydrothermal process is shown to grow TiO₂ nanorods on these nanowires to create a hierarchical nanoheterostructure that will lead to efficient photogenerated charge carrier separation and rapid transport of electrons to the substrate. This process simplifies nanowire growth by using commercially available and widely used FTO substrates without the need for an additional upstream Sn source and can be used as a high surface area host structure to many other hierarchical structures.

Giant white and blue light emission from Al(2)O(3) and ZnO nanocomposites

A new and general approach enabling us to amplify not only the bandgap emission of ZnO nanorods but also the defect emission of Al(2)O(3) is proposed. The light intensity of the band edge emission of ZnO nanorods can be improved by as much as 19 times after the decoration of Al(2)O(3) layers. Moreover, white light emission arising from Al(2)O(3) defects in ZnO/Al(2)O(3) nanostructures also shows a large enhancement factor of 12 times. Our new strategy offers an alternative possibility to create strong white and blue light-emitting devices.

A new route to self-assembled tin dioxide nanospheres: fabrication and characterization

Nearly monodispersed self-assembled tin dioxide (SnO2) nanospheres with intense photoluminescence (PL) were synthesized using a new wet chemistry technique. Instead of coprecipitating stannous salts, bulk tin (Sn) metal was oxidized at room temperature in a solution of hydrogen peroxide and deionized water containing polyvinylpyrrolidone (PVP) and ethylenediamine (EDA). SnO2 nanocrystals were produced with diameters of approximately 3.8 nm that spontaneously self-assembled into uniform SnO2 nanospheres with diameters of approximately 30 nm. Analysis was performed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-vis absorption spectroscopy, PL spectroscopy, and fluorescence lifetime measurements. The SnO2 nanospheres displayed room-temperature purple luminescence with an intense band at 394 nm (approximately 3.15 eV) and a high quantum yield of approximately 15%, likely as a result of emission from the surface states of SnO2/PVP complexes. The present study could open a new avenue to large-scale synthesis of self-assembled functional oxide nanostructures with technological applications as purple emitters, biological labels, gas sensors, lithium batteries, and dye-sensitized solar cells.