Highly-stable flexible pressure sensor using piezoelectric polymer film on metal oxide TFT

In this study, a flexible pressure sensor with highly stable performance is presented. The pressure sensor was fabricated to work under low voltage conditions by using a high mobility amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) and a stretched polyvinylidene fluoride (PVDF) film. To prepare a stable sensor suitable for practical use, we designed a device structure that shields ambient noise by grounding the control gate. The shielding structure significantly improves the stability of the device. Moreover, the sensor was fabricated on a flexible substrate and delaminated via a laser lift-off (LLO) technique to meet the urgent needs for flexibility. The pressure sensor showed good sensitivity and reliability over a pressure ranging from 0 to 75 kPa which covers the human touch pressure range. Especially, good linearity over a wide pressure range and high stability over 1000 repeated loadings were realized. Due to the simple structure, the pressure sensor demonstrates the advantage of being inexpensive to be manufactured and holds the potential to be integrated into the display backplane. Therefore, the proposed sensor has great potential in the production of flexible touch screens, human-machine interacting applications, and even electronic skins in the future.