Fiber Electronics

Abstract

Fiber materials, including natural fibers discovered thousands of years ago and man-made fibers invented over a century ago, are indispensable for the basic life of humankind, as, for instance, they have been woven into textiles to keep us warm since the ancient times. The resulting textiles have also gradually become a key part of fashion, particularly in the past centuries. In the most recent decades, fiber materials have experienced a revolution into a new epoch of electronic devices with various functions based on the rapid advance of information technology and artificial intelligence. Fiber-shaped electronic devices may harvest energy, store energy, light, and detect environmental changes both in vitro and in vivo, and many new fiber-shaped electronic devices such as transistors are also emerging. Compared with traditional bulky and film-like devices, ultraflexible fiber-shaped electronic devices may closely and stably adhere to irregular substrates and accommodate complex deformations such as twisting and stretching. They have been thus extensively explored for a variety of promising fields such as soft robotics, biomedical engineering, and smart life. They can be also woven into electronic textiles that breathe freely or that are integrated into/onto the human body, particularly for use in wearable and implantable materials, which was previously unavailable for their traditional counterparts. The boom of electronic fiber materials and devices gives birth to a new research field or even discipline, i.e., fiber electronics, which I may name here. Functional materials play a critical role in the advance of fiber electronics. To further push fiber electronics ahead, it is necessary and important to highlight the main achievements in this new area from the viewpoint of materials science, and therefore we have organized this special issue of Advanced Materials. For the collected sixteen articles, including 10 Reviews and 6 Progress Reports, the main efforts are made in summarizing various fiber electronic materials, devices, and applications by taking advantage of the distinctive interface internally and externally from the one-dimensional configuration, and the remaining challenges and future directions are carefully explored too. As basic building blocks, fiber electrodes play a critical role in determining the performance of fiber-shaped electronic devices, so they have been explored intensively in the past decade. Fiber electrodes are discussed according to their composition (e.g., metal, carbon, polymer, and composite) and have been particularly compared for their mechanical, electrical, and electrochemical properties, which are highly important for the resulting fiber-shaped electronic devices. In this special issue, two promising candidates are considered: carbon nanotube and graphene, for fiber electrodes, with contributions to this discussion from Qingwen Li and co-workers (article number 1902028), Chao Gao and co-workers (article number 1902664), and Liangti Qu and co-workers (article number 1901979). The main kinds of fiber-shaped electronic devices that function for energy harvesting (e.g., solar cells, triboelectric and piezoelectric generators, fluidic generators, and water generators (reviewed by Zhong Lin Wang and co-workers in article number 1902549 and Jun Zhou and co-workers in article number 1902034)), energy storage (e.g., supercapacitors, metal-ion batteries, metal–air batteries, and lithium–sulfur batteries (reviewed by Chunyi Zhi and co-workers in article number 1902151, Xinbo Zhang and co-workers in article number 1901961, Yuan Chen and co-workers in article number 1902387, Liming Dai and co-workers in article number 1902779, and Guozhen Shen in article number 1901806)), lighting (e.g., organic light-emitting diodes, polymer light-emitting electrochemical cells, and inorganic electroluminescent devices (discussed by Kyung Cheol Choi and co-workers in article number 1903488)), and sensing (e.g., chroma