Comparison of gas sensor performance of SnO2 nano-structures on microhotplate platforms

Metal oxide nano-structures on microhotplate platforms have attracted a great deal of interest in gas sensor research for their potential to create both highly responsive and extremely portable gas sensors. Much of the current research on these sensors has focused upon the creation of hierarchical nanostructures, as van der Waals attraction between nanoparticles leads to agglomeration that impair sensor performance. In this research article, ink-jet printing onto microhotplates was explored as a method of avoiding nanoparticle agglomeration to produce an open film microstructure. Scanning electron microscopy was used to study the deposited thin nanoparticle film featuring an open microstructure free of large agglomeration. Sensor response and response times of ink-jet printed SnO2 nanoparticles were found to be comparable to hierarchical particle films when exposed to methane and carbon monoxide in a background of dry air. Both the SnO2 nanoparticles and microspheres had superior response compared to SnO2 micron-size particles due to increased surface area of the nano-structures. This implies that proper control of the microstructure of the SnO2 nanoparticle films produces similar gas sensor performance to SnO2 hierarchical structures and has the potential for use in reproducibly manufacturing high-performance gas sensors.