Flexible paper based piezo-resistive sensor functionalised by 2D-WSe₂ nanosheets

High-performance electronics demand extremely sensitive piezo-resistive sensors with important features such as low-fabrication cost, easy implementation, low power consumption and high-pressure sensitivity over broad pressure range. Herein, we report a flexible piezo-resistive paper-based device functionalised by WSe₂ nanosheets. An efficient and low-cost fabrication strategy using Whatman filter paper and tissue paper is adopted for versatile sensing applications. The WSe₂ nanosheets were synthesized by high-yield and size-controlled liquid phase exfoliation technique. The flexible WSe₂ nanosheets-paper sensor shows excellent response in broad pressure range of 1 Pa-100 kPa with exceptionally high sensitivity of 29.24 kPa^-1, current responsivity of 70 and response time of 100 ms. The pressure sensor is also employed to recognize the pressure generated due to finger tapping. Encouragingly, the piezo-resistive sensors can also sense extremely small pressure differences of about 1.4 Pa generated by water drops.