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Creators/Authors contains: "Yang, Xiangxing"

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  1. Abstract

    Electrodermal activity (EDA) is a popular index of mental stress. State-of-the-art EDA sensors suffer from obstructiveness on the palm or low signal fidelity off the palm. Our previous invention of sub-micron-thin imperceptible graphene e-tattoos (GET) is ideal for unobstructive EDA sensing on the palm. However, robust electrical connection between ultrathin devices and rigid circuit boards is a long missing component for ambulatory use. To minimize the well-known strain concentration at their interfaces, we propose heterogeneous serpentine ribbons (HSPR), which refer to a GET serpentine partially overlapping with a gold serpentine without added adhesive. A fifty-fold strain reduction in HSPR vs. heterogeneous straight ribbons (HSTR) has been discovered and understood. The combination of HSPR and a soft interlayer between the GET and an EDA wristband enabled ambulatory EDA monitoring on the palm in free-living conditions. A newly developed EDA event selection policy leveraging unbiased selection of phasic events validated our GET EDA sensor against gold standards.

     
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  2. Abstract

    In the past few years, ultrathin and ultrasoft epidermal electronics (a.k.a. e‐tattoos) emerged as the next‐generation wearables for telemedicine, mobile health, performance tracking, human‐machine interface (HMI), and so on. However, it is not possible to build an all‐purpose e‐tattoo that can accommodate such a wide range of applications. Thus, the design, fabrication, and validation of modular and reconfigurable wireless e‐tattoos for personalized sensing are reported. Such e‐tattoos feature a multilayer stack of stretchable layers of distinct functionalities—a near field communication (NFC) layer capable of wireless power harvesting and data transmission, a functional circuit layer, and a passive electrode/sensor layer. These layers can be disassembled and swapped out multiple times to form different e‐tattoos of different sensing capabilities. Such modular and wireless e‐tattoos can be rapid‐prototyped via a dry, digital, and cost‐effective fabrication process—the “cut‐solder‐paste” process. They have been successfully applied to wirelessly measure a variety of biometrics.

     
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