An In2O3 nanowire-like network fabricated on coplanar sensor surface by sacrificial CNTs for enhanced gas sensing performance

Metal oxide quasi-one-dimensional (quasi-1D) nanostructures have a very good gas-sensing performance due to their large surface area and porous structures with a less agglomerated configuration. However, the well-designed fragile nanostructures could be easily destroyed during the conventional fabrication process of gas sensors. Herein, we presented a novel materials-sensor integration fabrication strategy: on basis of screen printing (SP) technology and calcination, micro-injecting (MI) was introduced into the fabrication process of sensors, which was named as SPMIC, to obtain In2O3 nanowire-like network directly on the surface of coplanar sensors array by structure replication from sacrificial carbon nanotubes (CNTs). The obtained In2O3 nanowire-like network exhibited an excellent response (electrical resistance ratio Ra/Rg), about 63.5, for100 ppm formaldehyde at 300 °C, which was about 30 times larger than that of compact In2O3 nanoparticles film (non-network film). The enhanced gas-sensing properties were mainly attributed to the high surface-to-volume ratio and the nanoscopic structural properties of materials. Furthermore, the SPMIC could be employed not only in the preparation of other metal oxide nanowire-like network, but also in the fabrication of coplanar gas sensors arrays on the required sites with different materials.