Flexible temperature sensors based on two-dimensional materials for wearable devices

Among the various functionalities of flexible devices, the sensing of temperature is an important task that is commonly required in wearable devices. As atomically thin two-dimensional (2D) materials have outstanding physical and chemical properties and extreme flexibility, those are good candidates for sensing materials for flexible temperature sensors. This review discusses the development trends in flexible temperature sensors using 2D materials, including graphene, transition metal dichalcogenides, MXene, and black phosphorus. The basic principles and material properties of the temperature sensors are summarized in this review. The sensing performances of the flexible temperature sensors for wearable applications are summarized and discussed.