Some of the biggest consumer electronics firms are planning flexible backplane-based displays, organic semiconductors - with organic semiconductors as the driving force.
SmartKem CEO Steve Kelly and Michael Cowin, head of product development, discuss the outlook for organic semiconductors.
Recent announcements by LG and Samsung of their intentions to launch flexible e-paper and OLED products have given serious traction to the belief that printable and flexible electronics are set to become high growth markets in the very near future.
Recent market research reports from IDTechEx suggest that the printed electronics market is predicted to exceed a staggering $300 billion (€228 billion) in the next 15 years. The number of display-based products currently on the market, along with a redefined generation of highly flexible, lightweight and 'unbreakable' products, makes these predictions increasingly credible.
At the forefront of the drive to realise flexible displays is the rapid advancement of new materials that allow the cost-effective production and delivery of products with novel form factors. Key to achieving this is the capability to manufacture thin-film transistor (TFT) backplanes that are high-performance, stable and flexible.
A number of differing production techniques are currently being explored by manufacturers, such as traditional spin coating, inkjet, flexography and gravure printing. While one production technique has not become the de facto standard, one common theme does become clear: the advantages gained from the active materials being a solution-based system, or ink.
While there is a variety of differing semiconductor material options with the potential to meet the requirements of flexible display production, many come with potential shortcomings. These can include production compatibility or performance capability, when the flexibility of the eventual product and its associated backplane are considered.
One material that is gaining more attention to fulfil the requirement for flexible TFT backplanes is organic semiconductors - materials that exhibit inherent flexibility that can be processed in solution.
Until recently the key drawbacks of organic semiconductors were temperature stability and a low charge carrier mobility, which effectively limited how quickly the eventual TFTs driving the display frontplane could be switched. These limiting factors for traditional organic semiconductor materials has driven the development of a new generation of organic semiconductors with higher performance capabilities which, when combined with the potential for use with an array of traditional printing techniques, offer a unique and compelling capability to display manufacturers.
Organic thin-film transistors
Pioneering the development of formulated organic semiconductor inks to meet the needs of these emergent display markets is SmartKem. The availability of these high-performance, solution-based organic semiconductors opens the door to use with all production methods, while also offering the capability to fine-tune process parameters such as viscosity, surface tension and film thickness to meet the requirements of a wide range of device architectures.
These organic semiconductor materials are inherently stable in air, exhibit high temperature stability, require no annealing and, by coupling innovative technology and consultancy, can be tailored for easy incorporation into production processes.
Organic (O)TFTs (such as SmartKem's) manufactured using organic semiconductors exhibiting mobility's of 3-4cm2/V.s (at channel lengths of 4μm) and good bias stress stability , will give display manufacturers the ability to attain the desired flexible device architecture, while also delivering exceptional device performance for the first time.
A significant commercial opportunity for organic semiconductors currently exists for the manufacture of OTFT backplane circuits for robust, flexible displays. This new class of versatile, air-stable organic semiconductor formulations will allow the ease of processing and robust electrical high performance required for the delivery of a new class of flexible display backplane technologies.
Display manufacturers such as Panasonic, LG, Sony and Samsung have already stated their intent to move to printed OTFT backplanes, and make the transition to lower cost rugged displays, making this a market of significant promise.
SmartKem is a high-tech enterprise developing an exciting new technology platform, focusing on high-performance organic semiconductor materials that can be 'printed' onto lightweight, low-cost polymer films to deliver flexible circuits.
Documents and links
The UK-based company recently received funding to commercialise ink for flexible electronics production
Subscribe to +Plastic Electronics magazine
Subscribe to +Plastic Electronics magazine, published six times a year, for just £100/€110/$160. Find out more here