Multi-parameter paper sensor fabricated by inkjet-printed silver nanoparticle ink and PEDOT:PSS.

This work presents the evaluation of a multiparametric sensing device on paper fabricated by inkjet printing, for applications such as smart packaging-labeling and disposable biosensors where biocompatibility and low cost are key factors. The device is able to measure simultaneously relative humidity, temperature and compressive and tensile bending. Commercial silver nanoparticle ink and PEDOT:PSS were printed onto inkjet photo glossy paper using a drop-on-demand inkjet printer forming an interdigitated electrode array and a meander shaped micro-ribbon. Humidity measurements revealed that sensor response, which is effectively expressed by the relationship between paper substrate resistance and relative humidity was similar for both materials utilized as electrodes. Temperature coefficients of resistance (TCR) were extracted for Ag-nanoparticle and PEDOT:PSS - based temperature sensors respectively in the range of 25–45 °C. The bending tests indicated that both materials exhibited similar trend in tensile bending, with resistance increasing in a linear manner up to a maximum tensile length of 900 μm. Ag-nanoparticle ink outperformed PEDOT:PSS ink in terms of repeatability, sensitivity and hysteresis. In compressive bending measurements Ag-nanoparticle and PEDOT:PSS gauge factors exhibited similar gauge factor of opposite sign. Unlabelled Image • Paper can be used as an active material for sensing relative humidity with different inkjet-printed materials as electrodes • Metal-based and conductive polymer materials can be inkjet-printed and utilized as resistive temperature sensors • Compressive and tensile bending sensors can be incorporated onto inkjet glossy paper with mechanical deformation limit of 9% • Ag-nanoparticle bending sensors show greater mechanical durability than PEDOT:PSS sensors under long-term bending tests [ABSTRACT FROM AUTHOR]