Facile synthesis of SnO2 nanopowders on laser-patterned ITO electrodes for fast response NO2 gas sensors

This research focused on the synthesis of tin oxide (SnO2) by a facile sol–gel method because its advantage had a low-cost process. SnO2 was then annealed from 300℃ to 700℃ to obtain crystal nanopowders with different surface morphologies and grain sizes. In addition, ultraviolet laser processing equipment was used to fabricate an interdigitated structure on indium tin oxide (ITO) films coated on glass plates as an electrode layer of gas sensors. The annealed SnO2 nanopowder was drop-cast on the interdigitated ITO electrode as a gas detection layer. The developed gas sensors were used to detect air pollution. Moreover, a SEM, an XRD, and a four-point probe were applied to measure the morphologies, structural characteristics, and electrical properties of ITO thin films and SnO2 nanopowders, respectively. After gas detection tests, the gas sensor based on SnO2 nanopowders annealed at 600 ℃ demonstrated a relatively large response of 9.7