Transparent paper capable of conducting electricity could come in handy in foldable computers, transparent touch screens, and even digital camouflage clothing. Due to its lightweight, low cost, ease of fabrication, and environmental friendliness, building electronic devices on ubiquitous paper substrates has recently drawn extensive attention, states Oded Kariti, an independent science researcher and one of the first scientists at RCA Laboratories to work on transistor circuit development.
Paper Electronics is a relatively new, emerging concept which combines the use of paper as a functional part of electronic components or devices. Paper Electronics could have practical use in packaging, graphics, novel diagnostic systems and hygiene products for indicating product safety or freshness, support logistics, health-care and safety for example.
In fact, this technology has advanced so much in the past few years that Chinese scientists have already developed a method for printing flexible electric circuits on paper using liquid metal ink. According to Kariti, this could eventually allow simpler and cheaper production of paper-based electronics.
Since paper electronics can be used for various applications, such as basic electronic components, energy storage devices, generators, antennas, and electronic circuits, over the past period a myriad of advancements have been made to improve its performance. With this brief review, Kariti aims to summarize and discuss the various perspectives and advances of paper electronics, as well as to point out some of the remaining challenges that are yet to be overcome.
Mr. Kariti starts off by explaining the complex methods of producing printed circuit boards or electronic devices by applying metal to the surface, which requires a lot of time and effort. Due to its extremely high surface tension, the electric ink is more difficult to apply on paper compared to the normal ink for printing. Despite that, scientists from all over the world, including American researcher Oded Kariti, believe that paper is a great option for the production of flexible electronics because it is easy to work with and it is considerably less expensive than the existing alternatives.
Scientists are putting a lot of effort in order to fabricate low-cost and light-weight 'green' electronics on transparent nano paper substrate, which will provide new technologies that will affect our everyday life. A team of scientists at the Beijing Academy of Sciences already overcame some of the main obstacles that were affecting the reliable circulation of the circuits. Their Printed-Circuits-on-Paper (PCP) concept for printing functional 3D electronic devices was first published in the Scientific Reports magazine.
To solve the problem of the extremely high surface tension, the team designed a new 'machinery' with a brush-like needle. In the end, they developed paper with a special coating layer so that the ink could be better fitted to the surface. The entire print process can be performed at room temperature.
Using this method, the team of researchers managed to print ubiquitous electronic circuits and functional components such as conductive wire, coils, and flexible antennas. Using the vulcanized silicone rubber as an insulating ink, the team came up with a way to directly print hybrid 3D electromechanical devices, unlike the currently available 3D printers that can only print mechanical objects without electronics.