Organic Field-Effect Transistor-Based Ultrafast, Flexible, Physiological-Temperature Sensors with Hexagonal Barium Titanate Nanocrystals in Amorphous Matrix as Sensing Material

Organic field-effect transistors (OFETs) with hexagonal barium titanate nanocrystals (h-BTNCs) in amorphous matrix as one of the bilayer dielectric systems have been fabricated on a highly flexible 10 mu m thick poly(ethylene terephthalate) substrate. The device current and mobility remain constant up to a bending radius of 4 mm, which makes the substrate suitable for wearable e-skin applications. h-BTNC films are found to be highly temperature-sensitive, and the OFETs designed based on this material showed ultraprecision measurement (similar to 4.3 mK), low power (similar to 1 mu W at 1.2 V operating voltage), and ultrafast response (similar to 24 ms) in sensing temperature over a range of 20-45 degrees C continuously. The sensors are highly stable around body temperature and work at various extreme conditions, such as under water and in solutions of different pH values and various salt concentrations. These properties make this sensor unique and highly suitable for various healthcare and other applications, wherein a small variation of temperature around measured at an ultrahigh speed.