• graphene
• humidity
• PEDOT:PSS
• pH
• sensor

In the last 20 years, joint efforts in different research fields have given way to the development of new materials and technologies enabling a wide range of new applications in wearable electronics, mobile healthcare, well-being as well as environmental monitoring. Among these, great attention has been focused on wearable sensors that could be fabricated on flexible substrates for the early prediction of diseases through the non-invasive analysis of body fluids like sweat and urine. This thesis aims to fabricate sensors on flexible substrates through the use of inkjet printing technique (IJP). In particular, the design, fabrication and characterization of two sensors for the detection of pH and humidity levels, suitable for wearable applications on flexible substrates like polyimide and paper, is presented. IJP has been exploited as the method of choice, since it allows the definition of precise structures at the micrometer scale on several flexible substrates. Such technique has been combined with the use of novel inks (i.e., inks based on two-dimensional materials) as well as more mature functional materials. In particular, the pH and humidity sensors have been printed using graphene and PEDOT:PSS inks, respectively. The fabrication process has been optimized while tweaking the fabrication parameter space. Sensors’ figure of merit such as sensitivity has been evaluated in detail for both the pH and humidity sensors, through an extensive electronic measurement activity.