Fe-doped ZnSnO3 cubes for high-performance detection of formaldehyde

ZnSnO3 is a typical metal semiconductor oxide (MOS), which has wide-band gap, n-type transport characteristics and excellent gas sensing performance. Fe doping plays a pivotal role in enhancing the formaldehyde sensing performance of ZnSnO3. In this paper, Fe-doped ZnSnO3 cubes were prepared successfully by a simple co-precipitation method. A series of characterization results show that Fe-doped ZnSnO3 is a cubic structure with uniform size of about 1.1 μm, and Fe doping increases the specific surface area and oxygen vacancy, which is responsible for the enhanced sensing performance. The gas-sensing tests show that Fe-doped ZnSnO3 cubes have a significant selectivity for formaldehyde gas, and the response value of Fe-doped ZnSnO3 cubes (3 mol%) to 100 ppm formaldehyde gas is about 5 times that of pure ZnSnO3 at 200 °C. In addition, the sensor has a fast response/recovery time (12/12 s), good recovery and reproducibility. Its excellent sensing performance is attributed to Fe doping, which leads to more defects and active sites in Fe-doped ZnSnO3 gas sensor. This work confirms that Fe-doped ZnSnO3 is a promising preparation scheme for formaldehyde sensors.