Highly deformable liquid-state heterojunction sensors

Abstract

Mechanically deformable devices and sensors enable conformal coverage of electronic systems on curved and soft surfaces. Sensors utilizing liquids confined in soft templates as the sensing component present the ideal platform for such applications, as liquids are inherently more deformable than solids. However, to date, liquid-based devices have been limited to metal lines based on a single-liquid component given the difficulty in the fabrication of liquidbased junctions due to intermixing. Here, we demonstrate a robust platform for the fabrication of liquid-liquid 'heterojunction' devices, presenting an important advancement towards the realization of liquid-state electronic systems. The device architecture and fabrication scheme we present are generic for different sensing liquids, enabling demonstration of sensors responsive to different stimuli. As a proof of concept, we demonstrate temperature, humidity and oxygen sensors by using different ionic liquids, exhibiting high sensitivity with excellent mechanical deformability arising from the inherent property of the liquid phase.

Mechanically Durable and Highly Stretchable Transistors Employing Carbon Nanotube Semiconductor and Electrodes

“…[ 17 ] However, many of the stretchable transistors developed to date contain fragile components, such as buckled Al 2 O 3 membranes, [ 20 ] gold thin fi lms, [ 21,22 ] or liquid metals. [ 23 ] For example, liquid-based devices [ 24 ] have the potential disadvantage of leakage in response to a puncture. We describe a with high density and an average thickness of ≈1.5 nm ( Figure S3, Supporting Information).…”

Emerging flexible and wearable physical sensing platforms for healthcare and biomedical applications

“…Generally, liquid-state sensors adopt a microfluidics-based device configuration to confine conductive liquids within soft elastomeric substratebased templates. Microfluidics-based sensor technology has seen rapid progress in an array of applications, particularly in numerous chemical and biological assays, owing to the unique advantages it offers, such as high device sensitivity and adaptability, minute sample quantity, low power requirements, and low fabrication costs 19,102,103 . Employing only a small volume of working fluid, an external load may be detected and quantified based on the variations in the electrical parameters of the device.…”

Stretchable‐Fiber‐Confined Wetting Conductive Liquids as Wearable Human Health Monitors

“…Generally, only one electric signal, such as the amplitude, has been used to monitor the human behaviors in early reports. [25][26][27][28][29][30][31][32][33] Considering the specificity of the PD, we used two signals-amplitude and frequency-providing more reliable diagnosis of PD. Furthermore, the fabricintegratable feature of this IL/fiber stretchable conductor could also be used for sport injury protection.…”

“…Especially at a larger strain, such as >100%, poor long-term durability might exist due to material delamination and/or local fracturing in the conductor components. [29] To solve this mechanics-mismatch problem, liquid conductors, including metallic liquids, [30] ionic liquids [31] /gels [32] or their mixtures, [33] have been proposed since they have lower Young's modulus than that of solids. Although intense research efforts have been devoted to generate diverse liquid/solid type tactile sensors, the basic liquid/solid interaction during the stretching of the supports has not yet been well studied.…”