Feb 24, 2009
Functionalized ZnO makes a better nose
In order to raise the sensitivity of gas sensors based on metal oxides, commercial devices usually operate at 300-500 °C to enhance the surface molecular sorption kinetics. Due to the ultrahigh surface to volume ratio of nanostructures, chemical sensing based on nanostructures has attracted enormous attention and ZnO is a particularly promising candidate for future-generation devices.
Although unmodified ZnO nanostructure sensors clearly have a role to play in gas sensing, the high-temperature operation of these oxide sensors is energy-consuming and not favorable in many cases, particularly in an explosive environment.
Now, Taiwanese researchers, led by Jr-Hau He from the National Taiwan University, have demonstrated that a plasma-polymerized acrylonitrile (PP-AN)/ZnO nanobelt (NB) nanosensor provides a better oxygen-sensing response than a bare ZnO NB nanosensor thanks to the sorption nature of the polymer. Furthermore, with the aid of ultraviolet light, significant enhancements in the response of PP-AN/ZnO NB nanosensors have been obtained at low temperature.
"Lowering the working temperature of the sensor can avoid structural deterioration of the device, which can cause instability in the response," said Jr-Hau He.
The polymer-functionalized ZnO nanomaterial being developed by the team paves the way for gas sensors with a lower operating temperature, reduced power consumption, and enhanced sensitivity.
This work was published in Nanotechnology.
About the author
Mr C. H. Ho, is a research assistant and Mr C. Y. Chen is a Ph.D student based at the Small Lab led by Prof. Jr-Hau (JH) He at the Institute of Photonics and Optoelectronics, Department of Electrical Engineering, National Taiwan University, Taiwan. The Small Lab is currently is exploring 1D nanostructures, together with electrical and optoelectronic measurements, and the application of the resulting nanostructures.