Paper-based wearable electronics

Abstract

Skin-interfaced wearable electronics can find a broad spectrum of applications in healthcare, human-machine interface, robotics, and others. The state-of-the-art wearable electronics usually suffer from costly and complex fabrication procedures and nonbiodegradable polymer substrates. Paper, comprising entangled micro-or nano-scale cellulose fibers, is compatible with scalable fabrication techniques and emerges as a sustainable, inexpensive, disposable, and biocompatible substrate for wearable electronics. Given various attractive properties (e.g., breathability, flexibility, biocompatibility, and biodegradability) and rich tunability of surface chemistry and porous structures, paper offers many exciting opportunities for wearable electronics. In this review, we first introduce the intriguing properties of paper-based wearable electronics and strategies for cellulose modifications to satisfy specific demands. We then overview the applications of paper-based devices in biosensing, energy storage and generation, optoelectronics, soft actuators, and several others. Finally, we discuss some challenges that need to be addressed before practical uses and wide implementation of paper-based wearable electronics.

Hospitals and Laboratories on Paper-Based Sensors: A Mini Review

“…Many paper-based sensors were designed for the handheld detection of strain pressure based on the change of the resistance, capacitance, and triboelectric current signal [ 41 ]. Flexible pressure sensors attracted gradually increasing attention owing to their great potential applications in wearable devices and human–computer interaction interfaces [ 42 ]. Especially in practical detections, people have urgent demands for pressure sensors with high sensitivity, a wide measurement range, and low costs.…”

Suitability of Paper-Based Substrates for Printed Electronics

“…Paper has been evaluated as a substrate for thermochromic and electrochromic displays, resistive memory devices, transistors, capacitors, disposable radio frequency identification (RFID) tags, batteries, photovoltaic cells, and sensors and actuators [4][5][6]12,[17][18][19]. In recent years, the use of paper-based substrates in diagnostics, pharmaceutical, energy harvesting, and wearable applications has grown due to paper's high breathability consequently from porosity, flexibility, and sustainability [6,20]. Examples of these devices include wearable pressure and humidity sensors, thermoelectric generators, as well as smart bandages [20].…”

“…In recent years, the use of paper-based substrates in diagnostics, pharmaceutical, energy harvesting, and wearable applications has grown due to paper's high breathability consequently from porosity, flexibility, and sustainability [6,20]. Examples of these devices include wearable pressure and humidity sensors, thermoelectric generators, as well as smart bandages [20]. Paper-based electronics have also been demonstrated with high-volume mass-manufacturing techniques.…”

“…Printed conductive tracks are important building blocks for any electronic device, thus highlighting the good printability properties on paper substrates combined with good electronic performance. The most widely used printing methods with paper-based electronics include screen printing, gravure, flexography, and inkjet printing [7,8,10,20]. To avoid absorption or penetration of functional materials into the paper structure and to achieve high conductivity, particle-based conductive metal inks or pastes are typically used with paper-based substrates [6].…”

Flexible organic optoelectronic devices on paper

“…With the increasing demand for product diversity, paper substrates are increasingly applied in organic optoelectronic devices, such as organic thin-film transistor (OTFT), organic solar cell (OSC), organic electrochromic device (OECD), and organic light-emitting device (OLED). Compared with traditional inorganic materials, organic materials have good flexibility and are more suitable for flexible substrates such as paper substrates ( Lee et al., 2019 ; Lim et al., 2021 ; Song et al., 2021 ; Sun et al., 2019 ; Xu et al., 2021 ). As a substrate for flexible electronic devices, paper has many unique advantages.…”