High sensitivity and fast response sensor for formaldehyde based on In2O3/Sn2O3 heterojunction

Modifying metal oxide semiconductor materials is a primary approach to enhance gas sensor performance, and heterojunction is a promising method to address cross-sensitivity issues in gas sensors. Sn 2 O 3 nanoflower-based substrates and In 2 O 3 /Sn 2 O 3 heterojunction structures were successfully synthesized by hydrothermal synthetic method. The gas-sensing performance of the In 2 O 3 /Sn 2 O 3 heterojunction-based gas sensor towards formaldehyde gas was investigated. The gas sensor based on In 2 O 3 /Sn 2 O 3 heterojunction exhibited higher sensitivity to formaldehyde gas compared to pure Sn 2 O 3 gas sensor at the same operating temperature. The response and recovery rates of the sensor were significantly improved as well. In addition, the In 2 O 3 /Sn 2 O 3 gas sensor exhibited lower response to interfering gases compared to its response to formaldehyde gas, thus demonstrating superior selectivity over the pure Sn 2 O 3 sensor. The result provides a research direction for the development of high-performance, highly selective, and rapid response formaldehyde sensors, which has certain reference significance for the advancement of gas sensor technology.