Scalable, sensitive, smart: the role of inkjet printing in next-generation chemiresistive gas sensors

Inkjet printing has rapidly emerged as a transformative technology for the fabrication of chemiresistive gas sensors, offering a scalable, low-cost, and material-efficient alternative to traditional microfabrication techniques. This review provides a comprehensive analysis of recent advancements in inkjet-printed gas sensors, with a particular focus on the integration of commercially available inkjet printing platforms. It begins with an overview of fundamental chemiresistive sensing principles, including gas-surface interactions, the role of oxygen adsorption, and enhancement strategies such as graphene integration and molecular imprinting. The discussion then shifts to critical aspects of ink formulation, substrate compatibility, and optimization of the inkjet printing process. Key performance parameters including sensitivity, selectivity, operating temperature, and stability are compared across various material systems, supported by tabulated data. Furthermore, the role of industrial inkjet printers in facilitating precision and reproducibility in sensor fabrication is highlighted. The review concludes with a critical discussion of current limitations including ink instability, limited selectivity, and high operating temperatures, and outlines future research directions aimed at enabling intelligent, low-power, and flexible gas sensing systems for next-generation Internet of Things (IoT) applications.