Advances in low-working-temperature gas sensors.

Gas sensors are more and more requested nowadays for several applications like industrial pollution, food safety, human's health. Measuring the variation in conductance or capacity of a sensing material is the cheapest way to realize a device. Metal oxide semiconductors-based gas sensors have been extensively explored due to their high sensing response, cost-effectiveness, long-term stability, and simple fabrication. Recent trends deal with the use of nanostructured and low-dimensional materials to boost the sensing capabilities. Gas sensing is achieved at high temperature, but reduction in power consumption is essential for long-term usage; moreover, room temperature operation is needed for explosive environment or if the sensor is in contact with the food. In this contribution we will focus on gas sensors based on nanowires, by investigating the effect of light activation for low-temperature operation. We will also review our latest achievements in developing paper sensors for food spoilage, where the sensing material is made of cellulose.