Koskinen Tomi, Juntunen Taneli, Tittonen Ilkka
Department of Electronics and Nanoengineering, Aalto University, P.O. Box 13500, FI-00076 Aalto, Finland.
Sensors (Basel). 2020 Sep 11;20(18):5188. doi: 10.3390/s20185188.
Emergent applications in wearable electronics require inexpensive sensors suited to scalable manufacturing. This work demonstrates a large-area thermal sensor based on distributed thermocouple architecture and ink-based multilayer graphene film. The proposed device combines the exceptional mechanical properties of multilayer graphene nanocomposite with the reliability and passive sensing performance enabled by thermoelectrics. The Seebeck coefficient of the spray-deposited films revealed an inverse thickness dependence with the largest value of 44.7 μV K at 78 nm, which makes thinner films preferable for sensor applications. Device performance was demonstrated by touch sensing and thermal distribution mapping-based shape detection. Sensor output voltage in the latter application was on the order of 300 μV with a signal-to-noise ratio (SNR) of 35, thus enabling accurate detection of objects of different shapes and sizes. The results imply that films based on multilayer graphene ink are highly suitable to thermoelectric sensing applications, while the ink phase enables facile integration into existing fabrication processes.
可穿戴电子产品中的紧急应用需要适合大规模制造的廉价传感器。这项工作展示了一种基于分布式热电偶结构和基于墨水的多层石墨烯薄膜的大面积热传感器。所提出的器件将多层石墨烯纳米复合材料的优异机械性能与热电学实现的可靠性和被动传感性能相结合。喷雾沉积薄膜的塞贝克系数显示出与厚度成反比的关系，在78纳米时最大值为44.7 μV/K，这使得较薄的薄膜更适合传感器应用。通过触摸传感和基于热分布映射的形状检测展示了器件性能。在后一种应用中，传感器输出电压约为300 μV，信噪比（SNR）为35，从而能够准确检测不同形状和尺寸的物体。结果表明，基于多层石墨烯墨水的薄膜非常适合热电传感应用，而墨水相能够轻松集成到现有的制造工艺中。
