Korean Engineers A Step Closer To Rolling Up Super Thin Computers Like A Sheet of Paper

For the last half a decade, flexible OLED displays gained more popularity than what was anticipated. The big players, especially #-Link-Snipped-# and LG Flexible OLED Display Smartphone Launch Next Month - Mass Production Begins Soon were the one of the few well known pioneers responsible for bringing the tech into mainstream. Researchers from around the globe have put their heads together to come up with newer technologies to build truly flexible electronic gadgets. Be it the Soap Bubble Screen Display Is Flexible & World's Thinnest, the Flexible OLED displays with 4K resolution developed by SEL by SEL or even more recent, the move by China based Flexible Smartphone's Time Is Now : Moxi Group to Ship 100,000 Devices This Year in 2016 alone, it's all an indication at the age of flexible screens is here. Rolling up smart displays when they are in an operating mode has already seen the light of the day with the advent of organic LEDs produced on a plastic substrate.

As research surrounding these flexible displays and electronics devices takes pace, a team of engineers from KAIST and POSTECH, Korea has become successful in developing super flexible OLEDs by making use of Graphene as a transparent electrode, which is a layer sandwiched between titanium dioxide (TiO2) and polymer.

Grouped and placed on top of each other, OLEDs have multiple super thin layers of glass or plastic substrates or foil such that two electrodes (cathode and anode) have different layers of organic compounds in between them. On applying voltage, electrons from cathode and positively charged particles from anode come together. When they reintegrate, energy is emitted in the form of a "photon", and thus OLEDs emit light.

What's interesting to note here is that one of the electrodes in OLEDs is usually transparent and depending upon which one it is, they are categorised as top-emission (for cathode) or bottom-emission OLEDs (for anode). In the latter one, the transparent anode makes the photons exit via its substrate. In most cases, Indium-tin-oxide (ITO) is used as the transparent anode, due to its solid properties such as low sheet resistance and high transparency and also because of its tried and tested manufacturing process. However, ITO is a costly element and is proven to be brittle and could crack on bending. This defeats the purpose.

Even though using Graphene as a substitute to ITO is a great choice because of the element's phenomenal chemical and physical properties, in results shown so far the efficiency of OLEDs based on either of them have little or no difference.

To crack this problem, the team of Korean electrical and mechanical engineers have come up with a new device structure through a process that involves fabrication of a transparent anode in a composite manner. They created a TiO2 layer with a hole-injection layer (HIL) and a high refractive index (high-n) of conducting polymers with a low refractive index (low-n) sandwich graphene electrodes.


With their new method, now Graphene based OLEDs have unparalleled power efficiency and ultra high external quantum efficiency (EQE). The devices created with these new OLEDs would not break even after 1000+ bending cycles at a radius 2.3 mm curvature.

Moreover, the researchers also found that TiO2 has an interesting toughening mechanism that deflects cracks, making it less prone to cracks caused by bending. This is the next step towards revolutionising the electronics industry and we are just on the verge of a new era where our gadgets won't be restricted to a certain shape or size.

What are your thoughts about the ultra thin, extremely flexible displays of the future? Share with us in comments below.

Source: Researchers Develop Highly Flexible OLEDs Using Graphene-Based Electrode