Hierarchical Wrinkles with Piezopotential Enhanced Surface Tribopolarity for High-Performance Self-Powered Pressure Sensor

Abstract

Achieving both high sensitivity and wide detecting range is significant for the applications of triboelectric nanogenerator-based self-powered pressure sensors (TPSs). However, most of the previous designs with high sensitivity usually struggle in a narrow pressure detection range (<30 kPa) while expanding the detection range normally sacrifices the sensitivity. To overcome this well-known obstacle, herein, piezopotential enhanced triboelectric effect realized by a rationally designed PDMS/ZnO NWs hierarchical wrinkle structure was exploited to develop a TPS (PETPS) with both high sensitivity and wide detecting range. In this PETPS design, the piezopotential derived from the deformation of ZnO NWs enhances its tribo-charge transferring ability; meanwhile, the hierarchical structure helps to establish a dynamically self-adjustable contact area. Benefiting from these advantages, the PETPS simultaneously achieves high sensitivity (0.26 nC cm −2 kPa −1 from 1 to 25 kPa, and 0.02 nC cm −2 kPa −1 from 25 to 476 kPa), fast response (46 ms), wide sensing range (1 to 476 kPa), and good stability (over 4000 cycles). In addition, the output charge density that is independent of the speed rate of driven force was adopted as the sensing signal of PETPS to replace the commonly used peak voltage/current values, enabling it more adaptive to accurately detect pressure variation in real applications.

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“…Moreover, the voltage signal remains stable at different frequencies (Figure c), which is beneficial for accurately detecting complex pressure changes. To quantitatively evaluate the sensitivity of the sensor, the sensitivity value was calculated according to the following formula (Figure d). , S = ( Δ V / V 0 ) / P where V 0 is the detectable minimum voltage, Δ V is the relative change of voltage, and P is the applied pressure. In the low-pressure range of 0–2.25 kPa, the macroscopic pores compress and form more conductive pathways, which greatly increase the conductivity and sensitivity (33.61 kPa –1 ).…”