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.