Soft, thin skin-mounted power management systems and their use in wireless thermography

Abstract

Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios.solid-state lithium-ion battery | multijunction solar cell | stretchable electronics | energy management | wearable technology R ecent ideas in materials science and mechanical engineering establish strategies for integrating functionality enabled by hard forms of electronics with compliant interconnects and soft packages to yield hybrid systems that offer low-modulus, elastic responses to large strain deformations (1-4). Such stretchable characteristics are qualitatively different from those afforded by simple mechanical bendability; the consequences are important because such properties allow for intimate, long-lived interfaces with the human body, such as the skin (5, 6), heart (7), and the brain (8), and for development of unusual device designs that derive inspiration from biology (9, 10). Many impressive examples of the utility of these concepts have emerged over the last several years, particularly in the area of biomedical devices, where work in skin-mounted technologies is now moving from laboratory demonstrations to devices with proven utility in human clinical studies (11, 12) and even to recently launched commercial products (13). Although schemes in high-frequency or ultrahigh-frequency wireless power transfer satisfy requirements in many important contexts (14, 15), opportunities remain for approaches in local generation and/or storage of power in ways that retain overall stretchable characteristics at the system level. Reported approaches to the former involve harvesting based on piezoelectric (16, 17), triboelectric (18), and thermoelectric (19) effects; the latter includes batteries (20-22) and supercapa...

Flexible, Stretchable, and Transparent Planar Microsupercapacitors Based on 3D Porous Laser‐Induced Graphene

“…Considering these properties and its ease of manufacturing and shaping, silicone rubber can be found in a wide variety of products, especially medical devices and implant. [6,[50][51][52][53] Here, for the silicone rubber-based in-plane wearable energy store devices, the performance durability has been investigated under various deformation such as stretching, bending, or twisting to simulate severe working condition. The 3D network structure facilitates the deformation and keeps the electrical conductivity during deformation, as shown in Figure 4a.…”

“…[1][2][3][4][5][6] Some of the most effective and practical technologies for electrochemical energy conversion and storage are batteries, fuel cells, and supercapacitors. [7][8][9][10][11][12][13][14][15] Among them, supercapacitors (SCs) have attracted intensive attentions due to their high power density and long lifecycle.…”

Inorganic semiconducting materials for flexible and stretchable electronics

“…85 Figure 5c (left) shows an optical image of a device that includes a temperature sensor and a wireless data transmission module, along with data storage, power regulation of a battery array and wireless power delivery system. This platform is capable of storing information on temperature changes of the skin in the memory and wirelessly transmitting this data.…”

“…Corresponding IR images show the responses from each stage of the evaluation (bottom right). Reprinted with permission from Lee et al 85 Copyright 2016 National Academy of Sciences…”

Toward Soft Skin‐Like Wearable and Implantable Energy Devices

“…[147] Another power management system uses thin, soft, and skin-compatible means for direct integration with the human body. [146] The system combined dual-junction compound semiconductor, millimeter-scale solar cells with bare die, chip-scale rechargeable lithium-ion batteries, integrated circuits for power management, and advanced near-field communication (NFC) module for wireless data processing. Optimized geometries in the serpentine wiring afford system-level, elastic biaxial stretchability up to 30% with a low effective modulus.…”