Park Chanju, Choi Munsu, Lee Suhui, Kim Hyunho, Lee Taeheon, Billah Mohammad Masum, Jung Byunglib, Jang Jin
Advanced Display Research Center (ADRC), Department of Information Display, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
Nanomaterials (Basel). 2022 Jun 21;12(13):2127. doi: 10.3390/nano12132127.
A piezoresistive sensor is an essential component of wearable electronics that can detect resistance changes when pressure is applied. In general, microstructures of sensing layers have been adopted as an effective approach to enhance piezoresistive performance. However, the mold-casted microstructures typically have quite a thick layer with dozens of microscales. In this paper, a carbon microstructure is formed by blue laser annealing (BLA) on a carbon nanotube (CNT) layer, which changes the surface morphology of CNTs into carbonaceous protrusions and increases its thickness more than four times compared to the as-deposited layer. Then, the pressure sensor is fabricated using a spin-coating of styrene-ethylene-butylene-styrene (SEBS) elastomer on the BLA CNTs layer. A 1.32 µm-thick pressure sensor exhibits a high sensitivity of 6.87 × 10 kPa, a wide sensing range of 278 Pa~40 kPa and a fast response/recovery time of 20 ms, respectively. The stability of the pressure sensor is demonstrated by the repeated loading and unloading of 20 kPa for 4000 cycles. The stretchable pressure sensor was also demonstrated using lateral CNT electrodes on SEBS surface, exhibiting stable pressure performance, with up to 20% stretching.
压阻式传感器是可穿戴电子产品的重要组成部分，在施加压力时能够检测电阻变化。一般来说，采用传感层的微结构是提高压阻性能的有效方法。然而，模铸微结构通常具有相当厚的层，厚度达数十微米。本文通过对碳纳米管（CNT）层进行蓝光激光退火（BLA）形成碳微结构，这将碳纳米管的表面形态转变为碳质突起，并且与沉积态的层相比，其厚度增加了四倍多。然后，通过在经蓝光激光退火处理的碳纳米管层上旋涂苯乙烯-乙烯-丁烯-苯乙烯（SEBS）弹性体制备压力传感器。一个厚度为1.32μm的压力传感器分别具有6.87×10 kPa的高灵敏度、278 Pa至40 kPa的宽传感范围以及20 ms的快速响应/恢复时间。通过对20 kPa进行4000次循环的反复加载和卸载，证明了该压力传感器的稳定性。还通过在SEBS表面使用横向碳纳米管电极展示了可拉伸压力传感器，其在高达20%的拉伸情况下表现出稳定的压力性能。
