Thermally stable and flexible paper photosensors based on 2D BN nanosheets

The market for printed and flexible electronics, key attributes for internet of things, is estimated to reach $45 billion by 2016 and paper-based electronics shows great potential to meet this increasing demand due to its popularity, flexibility, low cost, mass productivity, disposability, and ease of processing [1]. In the family of flexible electronics, solar-blind deep ultraviolet (DUV) photodetectors (PDs) can be widely applied in wearable applications such as military sensing, automatization, short-range communications security and environmental detection [2]. However, conventional flexible devices made of paper and plastic substrates are expected to have thermal issues due to their poor thermal conductivity. For instance, conventional paper has a very low thermal conductivity of 0.03 W/mK as that of plastic is 0.23 W/mK. As a result, it is required to increase the thermal conductivity of the substrates used for flexible electronics. In this work, we present flexible DUV paper PDs consisting of 2D boron nitride nanosheets (BNNSs) and 1D nanofibrillated celluloses (NFCs) with good detectivity (up to 8.05 × 1010 cm Hz1/2/W), fast recovery time (down to 0.393 s), great thermal stability (146 W/m K, 3-order-of-magnitude larger than conventional flexible substrates), high working temperature (up to 200 °C), excellent flexibility and bending durability (showing repeatable ON/OFF switching during 200-time bending cycles), which opens avenues to the flexible electronics.