Flexolighting

An EU funded project to develop the supply chain and production methodologies for the next generation of lighting products

	Tungsten	Halogen	CFL	LED	OLED
Lifetime (hrs)	800	5000	5000	50000	20000
Efficiency (lm/W)	8-10	20-30	50-60	60-80	40-100

Background

Effective lighting is essential for daily life, but replacements for the incandescent lamp that has been phased out are not ideal; CFLs contain mercury and inorganic LEDs have poor colour rendering index owing to significant UV/blue emission and increasing the risk of cancer. Warm, candle-like white colour with high efficiency is possible with OLED lighting. Moreover, OLEDs are free of UV, toxic materials and flickering. In addition, OLEDs have high CRI and most of the components can be recycled. They also permit novel design features and new form factors.

Participating in project has allowed partners to understand the benefits of OLED and the future of energy efficient lighting. It is clear that the main tangible benefits to the end user are even light dispersion and space utilisation. The software and hardware development work carried out during the project can be exploited further for customer and product development.

What has the project achieved:

RGBY emitters evaluated for WOLED suitability by VTE and OVPD

VTE, OVPD and solution processing technologies evaluated

Various WOLED architectures evaluated. Design of charge generation layer

Development of planarised steel

Development of OVPD, PVPD, PEALD, spatial ALD equipment

Development of transparent electrodes

Synthesis of transport materials and emitters and purification by vac. sublimation to 99.9%

Ink formulation and evaluation

Development of light extraction (LE) films

WOLED demonstrators

G8.5 OVPD (2.25x2.5m) equipment built, demonstrated to give superior device performance to current VTE production method, material utilisation of 70%, uniformity ±2%. Over 400 hours continuous operation.

High efficiency WOLEDs by OVPD

PEALD equipment built and commissioned. TFE demonstrated superior barrier than glass/glass encapsulation. WVTR < 8 x 10-5 gm-2 day-1

Large area (400x500mm) spatial ALD built. Barrier layers developed with WVTR < 1 x 10-3 gm-2 day-1

New hole injectors and transporters synthesised. Demonstrated to be superior to commercial materials

Hybrid OLED devices demonstrated where hole injector and transporter layers sequentially inkjet printed

VTE, OVPD, IJP, slot coating, spray coating and flexo printing deposition methods compared

Large area devices manufactured by OVPD

Transparent PEDOT deposited with conductivity in excess of 100Scm-1

Parylene demonstrated as effective barrier layer in conjunction with ALD deposited Al2O3. WVTR < 8 x 10-5 gm-2 day-1

Highly transparent (85%@550nm) and conducting (surface resistance <1Ω/□) graphene layers transferred onto glass

Planarisation of Ni coated steel. OLEDs successfully built on steel

Low cost light extraction film that doubles light output developed

Formulation of MoO3 ink and demonstration of its solution processability by IJP, slot and spray coating. Achieves comparable device performance to VTE ref.

WOLEDs with 113cd/A and 37lm/W fabricated by OVPD. With LE, efficiency 226cd/A and 74lm/W. Similar devices yield 60cd/A and 20lm/W by VTE. With LE 120cd/A and 40lm/W

AIXTRON involved in qualification of G8.5 OVPD equipment with OLED manufacturer. Developing an entire assembly of equipment to manufacture transparent electrode (PEDOT), OLED stack and encapsulation (parylene)

M&S designed and built a number of OLED prototype lamps. Intending to subcontract manufacture OLED panels for lighting in clothing stores

Beneq secured the sale of two ALD machines. PEALD shown to give faster deposition of metal oxide barrier, thus increasing productivity and enabling widespread acceptance by OLED manufacturers. Large area spatial ALD equipment developed in Flexolighting to be supplied to OLED manufacturers

Brunel invented patentable hole injectors and transporters available for licensing. In leveraging knowledge gained in developing OLED materials, processing and device architectures, Brunel is offering its facilities to SMEs to develop lighting products. OLED lighting will be incorporated into design and engineering MSc course in 2019. Commercialisation of LE film being pursued with film manufacturer

Tata Steel exploring commercial potential of graphene film and planarization layer.

Flexolighting Advantage

Publications

Electroluminescent Organic and Quantum Dot LEDs: The State of the Art, P Kathirgamanathan, L M Bushby, M Kumaraverl, S Ravichandran, S Surendrakumar, J Displ. Technol, Vol 11, No 5, 2015, 480, http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7073586