Flexible Piezoelectric-Coupling Organic Transistor-Based Press Sensors with Ferroelectric Charge-Transfer Complex Integrated Dielectrics

The development of flexible tactile sensors is critical for wearable electronics and human–computer interfaces. The porous structure and floating gate strategy in organic transistors are not easy to control and usually lead to a relatively large detection limit. To overcome these issues, effectively combining the piezoelectric effect into transistors in a simple way enhances the capacitance sensing and amplifies the readout characteristics. In this paper, solution-processed transistor-based pressure sensors were fabricated by using polar organic charge-transfer complex/dielectric polymer blend solutions. The hybrid dielectrics integrate well-distributed ferroelectric micro-/nanoparticles via tuning the doping ratio and exhibit a good insulating property. The devices presented a pressure sensitivity of 3.2 kPa^–1, good durability, and a low detection limit of 0.01 kPa. Moreover, the sensors were successfully introduced to build a sensor-robotic control system, switch, and haptic array keyboard. The well-integrated dielectric design method provides a simple and powerful way to construct flexible pressure sensors with great potential.