2 research outputs found
Atomic Force Microscopy Adhesion Mapping: Revealing Assembly Process in Inorganic Systems
There are still many unknowns regarding
assembly processes. In
this work, we demonstrate the capability of atomic force microscopy
(AFM) adhesion mapping in revealing the conditions that promote the
light-induced assembly of nanoparticles (NPs) on nanostructured surfaces
in inorganic systems, both in macro- and nanodomains. Gold (Au) NPs
and zinc oxide (ZnO) nanostructures are employed as the model materials,
and different characterization techniques are used for extracting
the relationship between the materials’ crystallinity, stoichiometry,
and morphology as well as surface adhesion mapping information. The
light-induced assembly of Au NPs is associated with the attraction
forces between the opposite surface charges of the NPs and preferential
ZnO sites, which can be identified by adhesion mapping. We show that
the yield of Au nanoclusters assembled onto the ZnO surface depends
on the crystallinity and stoichiometry of ZnO and is not due to the
roughness of the surface. The presented experiments demonstrate that
AFM adhesion mapping can be used as an invaluable tool for predicting
the strength and directions of assembly processes
Electrospun Granular Hollow SnO<sub>2</sub> Nanofibers Hydrogen Gas Sensors Operating at Low Temperatures
In
this paper, we present H<sub>2</sub> gas sensors based on hollow
and filled, well-aligned electrospun SnO<sub>2</sub> nanofibers, operating
at a low temperature of 150 °C. SnO<sub>2</sub> nanofibers with
diameters ranging from 80 to 400 nm have been successfully synthesized
in which the diameter of the nanofibers can be controlled by adjusting
the concentration of polyacrylonitrile in the solution for electrospinning.
The presence of this polymer results in the formation of granular
walls for the nanofibers. We discussed the correlation between nanofibers
morphology, structure, oxygen vacancy contents and the gas sensing
performances. X-ray photoelectron spectroscopy analysis revealed that
the granular hollow SnO<sub>2</sub> nanofibers, which show the highest
responses, contain a significant number of oxygen vacancies, which
are favorable for gas sensor operating at low temperatures