Very simple and sensitive low-cost PEDOT:PSS temperature and breathing sensor

During COVID-19 lock-down and consequently difficult access to research and teaching laboratories a very simple temperature sensor has been fabricated at home in the kitchen, demonstrating to the students the simplicity of basic organic electronic device preparation. To our great surprise the extremely simple fabricated flexible temperature sensor, with a PEDOT: PSS thin film deposited between coplanar contacts, realized just by a graphite pencil writing on commercial copy machine paper, exhibited a very high sensitivity, exceeding so far reported literature values and after a burn-in procedure also a very stable and perfectly ohmic electrical characteristics has been obtained. It could be shown that the PEDOT: PSS based sensors is about 5 times more sensitive with respect to temperature changes as compared to the drawn graphite based contacts alone. Reproducibility of the simple fabrication technique has been demonstrated with a second sensor of the same type. In this case a temperature calibration has been done and a possible application as sensitive breathing sensor has been demonstrated.