1 research outputs found
Fabrication of Bimetallic Au–Pd–Au Nanobricks as an Archetype of Robust Nanoplasmonic Sensors
Conventional
gas sensors work upon changes in mechanical or conductive
properties of sensing materials during a chemical process, which may
limit availabilities of size miniaturization and design simplification.
However, fabrication of miniaturized sensors with superior sensitivities
in real-time and label-free probing of chemical reactions or catalytic
processes remains highly challenging, in particular with regard to
integration of materials into a desired smaller volume without losing
the recyclability of sensing properties. Here, we demonstrate a unique
bimetallic nanostructure, the Au–Pd–Au core–shell–frame
nanobrick, as a promising archetype for fabrication of miniaturized
sensors at nanoscale. Upon analysis of the aqueous synthesis, both
ex situ and in situ, the formation of Au frames is consistent with
selective deposition and aggregation of NaBH<sub>4</sub>-reduced Au
nanoparticles at the corners and edges of cubic Pd shells, where the
{100} surfaces, capped by iodide ions, are growth-limited. By virtue
of the thin Pd shell (∼3.5 nm) sandwiched in-between the two
Au layers of the core and the frame, the Au–Pd–Au nanobrick
yields excellent optical sensitivity in hydrogen gas sensing, leading
to a large 13 nm spectral shift of light scattering between Pd and
PdH<sub><i>x</i></sub>. The composite nanostructure with
a size of ∼60 nm offers an archetype for miniaturized sensors
possessing label-free, real-time, and high-resolution probing abilities
and hence paves the way for fabrication of highly efficient nanosensors
via sustainable methods