UK displays and lighting knowledge transfer Network
Dr Eifion Jewell of UK Displays and Lighting Knowledge Transfer Network described it as the UK home of plastic electronics, flat panel displays and lighting. UK Displays & Lighting KTN (UKDL) is funded by the Technology Strategy Board to support UK Companies and Academics. Membership is free - join at the website www.ukdisplaylighting.net .
UKDL Activities Include
He listed the considerable membership of the associated initiatives.
It was noted in the Council for Science and Technology Review that Plastic Electronics is a high risk / high reward priority technology area. The academic structure is well established in OLED, PLED, OSC materials and deposition methods with £20M / yr funding from Research Councils (EPSRC).
The industrial base involves some multinational OEMs but is mainly SME driven with centres of Excellence funded through DTI/TSB, RDA's RG, & EU (e.g. PETeC, WCPC) and funded primarily through EPSRC (e.g. CIKC, OMIC). Collaborative R+D is funded by the UK Government through the Technology Strategy Board (previously by DTI), involving £48M since April 04 (Exceeded by Industry over same period). Geographical spread of this work is:
He saw the main challenges for the chemical industry to tackle as being:
- Solution processable small Molecule OLED materials for printing
- Polymer OLEDs appropriate for printing
- Solution processable "ITO replacement" materials
- High conductivity low temperature inks
- Barriers for polymer films
- Higher mobility SC materials
- Stable organic materials for atmospheric processing
- Thin high K high breakdown dielectrics etc
- Commercial volumes
He gave examples of printed and potentially printed electronics in the UK including the Plastic Logic flexible e-book, the Polymer Vision rollable displays, the CDT/Casio POLED television and the elumin8 ac electroluminescent e-posters. Using the term plastic electronics to encompass inorganic as well, he said that:
- Plastic Electronics will change forever how designers and manufacturers create products.
- Many early adopters of Plastic Electronics will NOT be electronics companies.
- Companies and designers will adopt Plastic Electronics to add value to their existing product portfolio - e.g. food packaging, medical sensors, illuminate clothing, wearable computing, disposable electronic games
- PV will be a major driver in development
- LIGHTING is becoming a major political battleground due to its historic inefficiency and wastage of power. Printable lighting for "Light tiles" and "Electronic wallpaper" is a realisable target.
UKDL will develop stronger networking links between UK Companies, share commercial goals and product vision, identify common technology hurdles and commercial barriers and help to solve the top ten problems. It will help commence commercial activities, sponsor directed research activities and collaborate in Industrial consortia. It will lobby the Technology Strategy Board and Government for a ring-fenced R+D fund over 5 Years. It will increase technical and commercial skills training in plastic electronics. There will be government sponsorship of flagship demonstrators, notably battery-free energy-neutral consumer electronic devices and intelligent, disposable, printed medical sensors for general use within healthcare.
Organic Materials Innovation Centre OMIC
OMIC was represented by Professor Mike Turner and by Professor Steve Yeates of the School of Chemistry, The University of Manchester, who spoke on "Processing Organic Electronic Devices: Nano-composite Materials and Structures". The motivation for this work is:
- Low cost large area printing and deposition.
- Lateral resolution initially at the high 10's of ìm's moving over time to 10ìm and below with excellent registration. As with displays how much, if any, of the market will sustainably require large feature sizes is a question of debate.
- Control of film thickness (5-10's nm) over large areas.
- Applicability to both rigid and flexible substrate moving towards roll-to-roll processing long term.
- Materials must maintain the key functional properties and development of optimal interfaces. Definition of appropriate purity
What needs to be patterned is:
- S/D/G definitely. Would argue that these will be the key critical features for lateral resolution
- Dielectric unlikely at fine feature size more likely for large area coverage 100's um2. Key issue defect free and uniform thickness.
- OSC unlikely at ultra fine feature size more likely for large area coverage 10's um2. Key issue defect free, uniform thickness and controlled morphology and interface.
- In all of this multi-layers and control of interface as well as orthogonal layer fluids critical.
The general patterning strategies are:
- The print/deposition process has a profound effect on materials performance whether through alignment (normal versus parallel to the substrate), structuring or interfacial phenomena.
- A key science theme is the understanding and control of such effects and may well lead to the identification of proprietary pre-treats or alignment protocols.
- This will become increasingly important as feature sizes fall below sub 10ìm and surface driven ordering becomes dominant.
As far as technology is concerned, he said that the Jury still out. There appears to be two schools of thought - continuous search for the optimal material and "I have what I have and make the best of it." The agenda likely to be set by the OEMs but an all inkjet world is unlikely. People are looking at hybrid solutions. The University of Manchester is investigating the design of novel functional materials for inkjet micro-deposition, modelling and underpinning science of the three key steps from Material to Drop generation→To Substrate interaction→To Coalescence, drying and 'film formation and Investigation of novel applications for inkjet micro-fabrication.
The funding for this work and the collaboration are extremely broad, including:
DTI/TSB - Hybrid, Interfaces, New OSC's, Sensors, Bio/Tissue
Home Office - Sensors
EPSRC - UK Centre for Next
Generation Inkjet Technology
EU FP6 - Digitex - Textile
Office of Naval Research (DLKTN)
Fuji Inkjet Colorants,
Royal Ten Cate (iTEX)
He is addressing the need for higher mobility p and n types that are seen as:
- solution processable,
- stable under environmental stress.
- capable of giving reproducible performance, device to device, over time, and over large area.
- Entirely deposited by additive processes
For example, the soluble version of pentacene called TIPS pentacene (Triisopropylethynylsilyl-pentacene) is receiving attention as are organic semiconductor-dielectric nanocomposites, where control of dilute solution rheology suitable for printing is an issue. Morphology control may lead to directed 'self assembly' and controlled crystallisation and more uniform device behaviour are sought together with affordability. Substrate interaction and drying are being optimised as well. Woven substrates are, of course, more difficult, but they are receiving attention as well.
For more attend Printed Electronics USA.