Hierarchically patterned self-powered sensors for multifunctional tactile sensing

TLDR

Flexible sensors are sought for tactile sensing and wearables, yet enabling material identification remains a challenge. The study reports a multifunctional sensor made of hydrophobic films and graphene/polydimethylsiloxane sponges. The sensor generates voltage signals via contact‑induced electrification when touching flat materials, enabling inference of material properties. The sensor achieves high‑pressure sensitivity (>15.22 kPa⁻¹), rapid response (<74 ms), durability (>3000 cycles), 1 K temperature resolution via thermoelectric effect, and low cost, enabling material identification.

Abstract

Flexible sensors are highly desirable for tactile sensing and wearable devices. Previous researches of smart elements have focused on flexible pressure or temperature sensors. However, realizing material identification remains a challenge. Here, we report a multifunctional sensor composed of hydrophobic films and graphene/polydimethylsiloxane sponges. By engineering and optimizing sponges, the fabricated sensor exhibits a high-pressure sensitivity of >15.22 per kilopascal, a fast response time of <74 millisecond, and a high stability over >3000 cycles. In the case of temperature stimulus, the sensor exhibits a temperature-sensing resolution of 1 kelvin via the thermoelectric effect. The sensor can generate output voltage signals after physical contact with different flat materials based on contact-induced electrification. The corresponding signals can be, in turn, used to infer material properties. This multifunctional sensor is excellent in its low cost and material identification, which provides a design concept for meeting the challenges in functional electronics.