Promod Kumar; M. M. Ahmad
Abstract
Gold nanoclusters embedded in titania (TiO2) matrix were synthesized by thermal spray method followed by thermal annealing in an inert atmosphere. The effect of annealing temperature on the plasmonic response and optical properties of gold nanocluster in titanium dioxide matrices have been investigated ...
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Gold nanoclusters embedded in titania (TiO2) matrix were synthesized by thermal spray method followed by thermal annealing in an inert atmosphere. The effect of annealing temperature on the plasmonic response and optical properties of gold nanocluster in titanium dioxide matrices have been investigated by using UV-visible absorption spectroscopy. The surface plasmon resonance (SPR) at metal-dielectric interface for gold nanoparticles has been observed for as deposited samples at 561.8 nm which degrade as a function of post annealing temperature. Field emission scanning electron micrographs confirm the presence of spherical nanoparticles whose size increases with post annealing temperature. The plasmonic resonance of noble metals at nanoscale is fundamentally and technologically important for light trapping photovoltaic and other applications.
Anand Kumar Tripathi; Mohan Chandra Mathpal; Promod Kumar; Vivek Agrahari; Manish Kumar Singh; Sheo Kumar Mishra; M. M. Ahmad; Arvind Agarwal
Abstract
The Ni doped titania nanostructures were synthesized by sol-gel method followed by calcination at 400°C for one hour. The optical band gap for these nanostructures indicates the red shift. The doped TiO2 nanostructures are spherical in shape. The pure TiO2 exhibits all the possible emission bands ...
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The Ni doped titania nanostructures were synthesized by sol-gel method followed by calcination at 400°C for one hour. The optical band gap for these nanostructures indicates the red shift. The doped TiO2 nanostructures are spherical in shape. The pure TiO2 exhibits all the possible emission bands while Ni-doped TiO2 nanoparticles show blue-green emission bands. The results suggest that Ni2+ replace some Ti 4+ in TiO2 lattice with tensile strain while TiO2 remained in the form of anatase phase, reduces its band gap energy. The synthesized TiO2 exhibits enhanced photoconducting properties. The work suggest that the titania based materials can have potential applications in photovoltaics, optoelectronic devices and photoconductors in replacement of expansive materials by controlling the compositions and morphology of the nanostructures.
Promod Kumar; M. M. Ahmad
Abstract
Nanoscale silver clusters were prepared in a soda-lime glass matrix through the ion-exchange (Ag+ ↔ Na+) method followed by thermal annealing in oxidizing atmosphere. The effects of annealing time and temperature on the plasmonic response and optical properties of silver nanocluster in glass matrices ...
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Nanoscale silver clusters were prepared in a soda-lime glass matrix through the ion-exchange (Ag+ ↔ Na+) method followed by thermal annealing in oxidizing atmosphere. The effects of annealing time and temperature on the plasmonic response and optical properties of silver nanocluster in glass matrices have been investigated by using UV-visible absorption spectroscopy and photoluminescence spectroscopy. The surface plasmon resonance of silver nanoparticles has been observed in annealed samples. The blue shift has been observed as a function of post-annealing time at a constant temperature. Transmission electron micrographs show the presence of spherical nanoparticles with a maximum particle size of 4-5 nm after annealing, which is consistent with Mie theory based results. The nano-sized Ag nanocluster on glass matrix is suitable as future prospective for potential applications in optical data storage.
