Interconnection Technologies for Flexible Electronics: Materials, Fabrications, and Applications.

Flexible electronic devices require metal interconnects to facilitate the flow of electrical signals among the device components, ensuring its proper functionality. There are multiple factors to consider when designing metal interconnects for flexible electronics, including their conductivity, flexibility, reliability, and cost. This article provides an overview of recent endeavors to create flexible electronic devices through different metal interconnect approaches, with a focus on materials and structural aspects. Additionally, the article discusses emerging flexible applications, such as e-textiles and flexible batteries, as essential considerations.

Recent advances in electrode development for biomedical applications.

Elaborate electrodes that enable adhesion to the skin surface and effectively collect vital signs are necessitated. In recent years, various electrode materials and novel structures have been developed, and they have garnered scientific attention due to their higher sensing performances compared with those of conventional electrode-based sensors. This paper provides an overview of recent advances in biomedical sensors, focusing on the development of novel electrodes. We comprehensively review the different types of electrode materials in the context of efficient biosignal detection, with respect to material composition for flexible and wearable electrodes and novel electrode structures. Finally, we discuss recent packaging technologies in biomedical applications using flexible and wearable electrodes.

Fractal Web Design of a Hemispherical Photodetector Array with Organic-Dye-Sensitized Graphene Hybrid Composites.

The vision system of arthropods consists of a dense array of individual photodetecting elements across a curvilinear surface. This compound-eye architecture could be a useful model for optoelectronic sensing devices that require a large field of view and high sensitivity to motion. Strategies that aim to mimic the compound-eye architecture involve integrating photodetector pixels with a curved microlens, but their fabrication on a curvilinear surface is challenged by the use of standard microfabrication processes that are traditionally designed for planar, rigid substrates (e.g., Si wafers). Here, a fractal web design of a hemispherical photodetector array that contains an organic-dye-sensitized graphene hybrid composite is reported to serve as an effective photoactive component with enhanced light-absorbing capabilities. The device is first fabricated on a planar Si wafer at the microscale and then transferred to transparent hemispherical domes with different curvatures in a deterministic manner. The unique structural property of the fractal web design provides protection of the device from damage by effectively tolerating various external loads. Comprehensive experimental and computational studies reveal the essential design features and optoelectronic properties of the device, followed by the evaluation of its utility in the measurement of both the direction and intensity of incident light.

Flexible submental sensor patch with remote monitoring controls for management of oropharyngeal swallowing disorders.

Successful rehabilitation of oropharyngeal swallowing disorders (i.e., dysphagia) requires frequent performance of head/neck exercises that primarily rely on expensive biofeedback devices, often only available in large medical centers. This directly affects treatment compliance and outcomes, and highlights the need to develop a portable and inexpensive remote monitoring system for the telerehabilitation of dysphagia. Here, we present the development and preliminarily validation of a skin-mountable sensor patch that can fit on the curvature of the submental (under the chin) area noninvasively and provide simultaneous remote monitoring of muscle activity and laryngeal movement during swallowing tasks and maneuvers. This sensor patch incorporates an optimal design that allows for the accurate recording of submental muscle activity during swallowing and is characterized by ease of use, accessibility, reusability, and cost-effectiveness. Preliminary studies on a patient with Parkinson's disease and dysphagia, and on a healthy control participant demonstrate the feasibility and effectiveness of this system.

Double-gate junctionless transistor for analog applications.

In this paper, analog performance of short channel symmetric double-gate junctionless transistor (DGJLT) is reported for the first time. The analog performance parameters, namely drain current (I(D)), transconductance (G(m)), transconductance/drain current ratio (G(m)/I(D)), early voltage (V(EA)), drain output conductance (G(D)), output resistance (R(o)), intrinsic gain (G(m)R(o)), gate to source capacitance (C(GS)), gate to drain capacitance (C(GD)) and unity gain cut-off frequency (f(T)) for the n-type DGJLT are systematically investigated with the help of extensive device simulations and are compared with conventional inversion mode symmetric double-gate transistor (DGMOS) of similar dimensions. DGJLT offers superior transconductance/drain current ratio and intrinsic gain in the subthreshold region than its inversion mode counterpart having same dimensions. However, DGMOS presents higher unity gain cut-off frequency which makes it suitable for high speed applications as compared to a DGJLT transistor.