Protecting your e-device (Day 226)
8th January 2015
They aren't cheap. The few production models available cost between £3,000-£7,000. But they have aspirations of being just 4 mm thick, are able to curve, 3D, have great colour, picture resolution and so on.
Interestingly, OLED's are made from organic semiconductors, along with other development products such as organic solar cells and organic electronic products including smart labels and wearable electronics.
OLEDs can be prepared with any color and with amazing brilliance - even when viewed from the side. They are flexible, lightweight and their efficiency can exceed standard light bulbs and approaches fluorescence lamps.
The production process for organic thin films is comparatively easy. An organic thin film is contacted by a noble metal on one side and a base metal on the other side.
When a voltage is applied, positive charges (holes) are injected into the organic material from one contact (Me1) and negative charges (electrons) from the other side.
When two different charge carriers meet, they neutralise each other and set free their energy as a light particle (photon).
However, organic semiconductors need protecting and are sensitive to water vapour and oxygen, which is why there is some good news from researchers - including chemical engineers - at the Indian Institute of Science (IISc), who have developed a new protective film which can significantly extend the life of organic semiconductors.
Their work has been published in Industrial and Engineering Chemistry Research in a paper called Water Vapor Barrier Material by Covalent Self-Assembly for Organic Device Encapsulation.
The new film is made of many ultrathin layers of polymers and other materials.
It consists of a layer of Nafion in between bilayers of two different polymers, which together sit on a Surlyn substrate. Nafion is the first of a class of synthetic polymers with ionic properties called ionomers, while Surlyn is made from ethylene acid copolymers with much reduced crystalline properties, thus making it flexible and durable.
The researchers say the protective film can increase the life of organic semiconductor devices by over 20 times.
The technology has the added bonus of using Nafion and Surlyn, both of which are commercially available.
Congratulations to everyone involved in this research, which has wide potential for industrial and leisure purposes.