Wearable Force Touch Sensor Array Using a Flexible and Transparent Electrode

Transparent electrodes have been widely used for various electronics and optoelectronics, including flexible ones. Many nanomaterial‐based electrodes, in particular 1D and 2D nanomaterials, have been proposed as next‐generation transparent and flexible electrodes. However, their transparency, conductivity, large‐area uniformity, and sometimes cost are not yet sufficient to replace indium tin oxide (ITO). Furthermore, the conventional ITO is quite rigid and susceptible to mechanical fractures under deformations (e.g., bending, folding). In this study, the authors report new advances in the design, fabrication, and integration of wearable and transparent force touch (touch and pressure) sensors by exploiting the previous efforts in stretchable electronics as well as novel ideas in the transparent and flexible electrode. The optical and mechanical experiment, along with simulation results, exhibit the excellent transparency, conductivity, uniformity, and flexibility of the proposed epoxy‐copper‐ITO (ECI) multilayer electrode. By using this multi‐layered ECI electrode, the authors present a wearable and transparent force touch sensor array, which is multiplexed by Si nanomembrane p‐i‐n junction‐type (PIN) diodes and integrated on the skin‐mounted quantum dot light‐emitting diodes. This novel integrated system is successfully applied as a wearable human–machine interface (HMI) to control a drone wirelessly. These advances in novel material structures and system‐level integration strategies create new opportunities in wearable smart displays.

[1]  Hye Rim Cho,et al.  A graphene-based electrochemical device with thermoresponsive microneedles for diabetes monitoring and therapy. , 2016, Nature nanotechnology.

[2]  T. Trung,et al.  Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human‐Activity Monitoringand Personal Healthcare , 2016, Advanced materials.

[3]  R. Ghaffari,et al.  Recent Advances in Flexible and Stretchable Bio‐Electronic Devices Integrated with Nanomaterials , 2016, Advanced materials.

[4]  Yong Ju Park,et al.  Graphene‐Based Flexible and Stretchable Electronics , 2016, Advanced materials.

[5]  Xiaodong Chen,et al.  Flexible and Stretchable Devices , 2016, Advanced materials.

[6]  Hye Rim Cho,et al.  Stretchable and Transparent Biointerface Using Cell‐Sheet–Graphene Hybrid for Electrophysiology and Therapy of Skeletal Muscle , 2016 .

[7]  Caofeng Pan,et al.  Self‐Powered High‐Resolution and Pressure‐Sensitive Triboelectric Sensor Matrix for Real‐Time Tactile Mapping , 2016, Advanced materials.

[8]  M. Kaltenbrunner,et al.  Ultraflexible organic photonic skin , 2016, Science Advances.

[9]  Taeghwan Hyeon,et al.  Designed Assembly and Integration of Colloidal Nanocrystals for Device Applications , 2016, Advanced materials.

[10]  Taeghwan Hyeon,et al.  A wearable multiplexed silicon nonvolatile memory array using nanocrystal charge confinement , 2016, Science Advances.

[11]  Taeghwan Hyeon,et al.  Cephalopod‐Inspired Miniaturized Suction Cups for Smart Medical Skin , 2016, Advanced healthcare materials.

[12]  Kyoung Won Cho,et al.  Thermally Controlled, Patterned Graphene Transfer Printing for Transparent and Wearable Electronic/Optoelectronic System , 2015 .

[13]  Hye Rim Cho,et al.  An endoscope with integrated transparent bioelectronics and theranostic nanoparticles for colon cancer treatment , 2015, Nature Communications.

[14]  Xiaodong Chen,et al.  Healable, Transparent, Room-Temperature Electronic Sensors Based on Carbon Nanotube Network-Coated Polyelectrolyte Multilayers. , 2015, Small.

[15]  Nae-Eung Lee,et al.  Transparent Stretchable Self-Powered Patchable Sensor Platform with Ultrasensitive Recognition of Human Activities. , 2015, ACS nano.

[16]  Zhong Lin Wang,et al.  Recent Progress in Electronic Skin , 2015, Advanced science.

[17]  Ji Hoon Kim,et al.  Wearable red–green–blue quantum dot light-emitting diode array using high-resolution intaglio transfer printing , 2015, Nature Communications.

[18]  Minbaek Lee,et al.  Stretchable carbon nanotube charge-trap floating-gate memory and logic devices for wearable electronics. , 2015, ACS nano.

[19]  Zhong Lin Wang,et al.  Dynamic Pressure Mapping of Personalized Handwriting by a Flexible Sensor Matrix Based on the Mechanoluminescence Process , 2015, Advanced materials.

[20]  Kwanghee Lee,et al.  Polymer-metal hybrid transparent electrodes for flexible electronics , 2015, Nature Communications.

[21]  Zhibin Yu,et al.  Large‐Area Compliant Tactile Sensors Using Printed Carbon Nanotube Active‐Matrix Backplanes , 2015, Advanced materials.

[22]  Dong Jun Lee,et al.  Transparent and Stretchable Interactive Human Machine Interface Based on Patterned Graphene Heterostructures , 2015 .

[23]  Yei Hwan Jung,et al.  Stretchable silicon nanoribbon electronics for skin prosthesis , 2014, Nature Communications.

[24]  F. Huo,et al.  Microstructured graphene arrays for highly sensitive flexible tactile sensors. , 2014, Small.

[25]  Sungjun Kim,et al.  Design of red, green, blue transparent electrodes for flexible optical devices. , 2014, Optics express.

[26]  Ji Hoon Kim,et al.  Reverse‐Micelle‐Induced Porous Pressure‐Sensitive Rubber for Wearable Human–Machine Interfaces , 2014, Advanced materials.

[27]  Dae-Hyeong Kim,et al.  Multifunctional wearable devices for diagnosis and therapy of movement disorders. , 2014, Nature nanotechnology.

[28]  R. Dauskardt,et al.  An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film , 2014, Nature Communications.

[29]  Yonggang Huang,et al.  Ultrathin conformal devices for precise and continuous thermal characterization of human skin. , 2013, Nature materials.

[30]  Zhong Lin Wang,et al.  High-resolution electroluminescent imaging of pressure distribution using a piezoelectric nanowire LED array , 2013, Nature Photonics.

[31]  M. Kaltenbrunner,et al.  An ultra-lightweight design for imperceptible plastic electronics , 2013, Nature.

[32]  Yi Cui,et al.  A transparent electrode based on a metal nanotrough network. , 2013, Nature nanotechnology.

[33]  Jang‐Ung Park,et al.  High-performance, transparent, and stretchable electrodes using graphene-metal nanowire hybrid structures. , 2013, Nano letters.

[34]  K. Ellmer.  Past achievements and future challenges in the development of optically transparent electrodes , 2012, Nature Photonics.

[35]  Benjamin C. K. Tee,et al.  Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. , 2011, Nature nanotechnology.

[36]  Sungjun Kim,et al.  BCP/Ag/MoO3 Transparent Cathodes for Organic Photovoltaics , 2011 .

[37]  Liangbing Hu,et al.  Emerging Transparent Electrodes Based on Thin Films of Carbon Nanotubes, Graphene, and Metallic Nanostructures , 2011, Advanced materials.

[38]  Kwang S. Kim,et al.  Roll-to-roll production of 30-inch graphene films for transparent electrodes. , 2010, Nature nanotechnology.

[39]  Properties of ITO/Cu/ITO Multilayer Films for Application as Low Resistance Transparent Electrodes , 2009 .

[40]  C. Guillén,et al.  ITO/metal/ITO multilayer structures based on Ag and Cu metal films for high-performance transparent electrodes , 2008 .

[41]  Yonggang Huang,et al.  Stretchable and Foldable Silicon Integrated Circuits , 2008, Science.

[42]  T. Someya,et al.  Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[43]  O. Heavens.  Thin-film Optical Filters , 1986 .

[44]  C. Kunz,et al.  Optical constants from the far infrared to the x-ray region: Mg, Al, Cu, Ag, Au, Bi, C, and Al 2 O 3 , 1975 .