1D Narrow-Bandgap Tin Oxide Materials: Systematic High-Resolution TEM and Raman Analysis

Abstract

We demonstrate for the first time the structure identification and narrow-bandgap property of 1D hybridized SnO/SnO2 nanoparticles derived from the calcination of a single-source precursor, i.e., tin(II) oxalate. Systematic Raman analysis together with high-resolution TEM (HR-TEM) measurements of the tin oxide samples were carried out by changing the calcination temperatures. These data revealed the simultaneous formation of 1D SnO/SnO2 in the rod particles that grew in air. It was also found that Sn(II) can be introduced by changing the concentration of Sn(II) salt in the precursor synthesis and the maximum temperature in calcination. Particles measuring 20~30 nm were sintered to produce tin oxide nanorods including tin monoxide, SnO. Photoabsorption properties associated with the formation of the SnO/SnO2 nanocomposites were also investigated. Tauc plots indicate that the obtained tin oxide samples had a lower bandgap of 2.9~3.0 eV originating from SnO in addition to a higher bandgap of around 3.5~3.7 eV commonly observed for SnO2. Such 1D SnOx/SnO2 hybrids via tin oxalate synthesis with this optical property would benefit new materials design for photoenergy conversion systems, such as photocatalysts.

Low-Dimensional Structures for Smart Materials and Composites: Preparation, Properties and Applications

“…These low-dimensional-structures can be tied into pillars and other geometrically organized macrostructures [15]. Manseki et al [16] presented an example of the structure recognition and narrow-bandgap properties of assembled SnO/SnO 2 nanoparticles, as derived from the thermal treatment in air of Tin(II) oxalate. The authors observed the simultaneous formation of SnO/SnO 2 nanoparticles with sizes of 20-30 nm arranged into nanostructured rods, as obtained during the heating step (350-600 • C range).…”