1D N-type SnO₂ nanofibers coexisted with P-type Co₃O₄ cubes for highly selective acetone sensor

SnO2/Co3O4 nanofibers using double jets electrospinning as low operating temperature gas sensor

“…Figure 8 , the sensing behavior of the composite is of n-type, it is due to the contribution of electrons being greater than that of holes. [32] The SnO 2 /Co 3 O 4 NFs sensor can return to the initial resistance when exposed to air after different concentrations of ethanol have been injected, which indicates that the Co 3 O 4 /SnO 2 NFs sensor has good reproducibility. The resistance of SnO 2 NFs changes differently after the response has been recovered.…”

“…[26,48,49] The Fermi energy levels of n-SnO 2 and p-Co 3 O 4 are different. [30,32,33,50] When the two kinds of NFs are combined, the electrons move from n-SnO 2 (work function 4.9 eV) to p-Co 3 O 4 (work function 6.1 eV) due to the Fermi energy level equilibrium effect. [51] The electron depletion layer is formed on the SnO 2 side, and the hole is transferred from p-Co 3 O 4 to n-SnO 2 .…”

“…It is reported that the SnO 2 /Co 3 O 4 nanoscale heterojunction has been formed, and the detection of acetone has been greatly improved. [32,33] Co-doped SnO 2 nanofibers showed the highest response toward 100-ppm ethanol. [1] The 0.5SnO 2 /0.5Co 3 O 4 sensor has a good response to C 6 H 6 at 350 • C. [30] The one-dimensional nanofiber material prepared by the electrospinning technology can significantly improve the response of the VOCs gas sensor due to its large specific surface area and high porosity.…”