The next big thing in consumer electronics could be flexible displays that roll up like a piece of paper. Ever since LG showed off a prototype screen at this year’s Consumer Electronics Show, rollable displays have been a hot research topic. Of course, making one prototype is not quite the same as achieving a flexible display that can stand up to the wear and tear of normal consumer usage. Now, researchers at the Korea Advanced Institute of Science and Technology (KAIST) have developed a component that could make flexible OLED (organic light-emitting diode) displays actually work—a transparent electrode made from graphene.
We expect that our technology will pave the way to develop an OLED light source for highly flexible and wearable displays, or flexible sensors that can be attached to the human body for health monitoring, for instance.
Traditionally, OLED displays are made from several layers of thin material sandwiched between two electrodes (a cathode and anode). When voltage is applied across the electrodes, electrons are exchanged and OLEDs release energy in the form of a photon, which is how they emit light. Indium-tin-oxide (ITO) is commonly used as an anode because it is transparent, resistant, and easy to manufacture. But it can be expensive and it is too brittle to withstand rolling and flexing.
Graphene, which is a sheet made from a single layer of carbon atoms, is a potential alternative to ITO. Certainly, graphene’s excellent electrical properties would help, but in this case it is especially promising because it’s so thin that it can be quite flexible and transparent. Despite these advantages, previous attempts at creating graphene-based transparent electrons have not achieved high enough performance. The KAIST team designed a new device structure that maximized the optical properties. The device was highly efficient and continued to operate well, even after being bent 1,000 times. The study is described in a paper that published in Nature Communications on June 2, 2016.