Part I: OLED for Displays and Lighting: Materials, Processing and Production
Professor Poopathy Kathirgamanathan, Professor of Electronic Materials Engineering, Wolfson Centre, Brunel University
The recent integration of OLEDs (organic light emitting displays) into mobile phones (Samsung-SDI) and OLED –TV’s (Sony) is a clear sign that the OLED technology is becoming accepted as a credible flat panel display technology. Recent reports of WOLED’s with efficiency in excess of 90 lm/W (comparable to fluorescent tube efficiency) has given an extra stimulus to Designers and Architects. WOLED’s are now routinely produced with efficiencies in excess of 40 lm/W and life-time of 10,000 hours at 1000 cdm-2. The market for OLED displays is predicted to be US$5.5 billion in 2015 and that for OLED Lighting is US$ 1.5 billion in 2015 according to Display Search (USA). A typical OLED device is a monolithic structure of hole injector, hole transporter, host +dopant (emitter), electron transporter and electron injector sandwiched between the anode and the cathode, at least one of which is transparent. To achieve efficient hole and electron injection into the emissive layer, the HOMO-LUMO of these materials has to be carefully matched.
There is a continuing demand for the reduction in power consumption, operating voltage and enhancement of the life-time of OLED’s. Charge transport (hole and electron) materials (pure or doped) are an integral part of any OLED. It has been reported that nearly 60% of the total electric power is lost through the charge transport layers, nearly 36% through etl and 5.7% through eil and the remainder through, hil, htl and hbl. The life time is also critically dependent on the nature of the charge transporters employed. Thus, there is an urgent need for electron transporters with high mobility and stability. The lecturer will present and demonstrate some strategies as to the selection of appropriate materials for efficient electron transport and injection resulting in lower operating voltage, higher efficiencies and longer life-time. The synthesis, characterisation and electrochemistry of some novel electron transporters and electron injectors will be highlighted. These materials are currently supplied in kg quantities to flat panel display manufacturers. Further, this seminar will address the following:
*High efficiency fluorescent blue emitters
*Low cost phosphorescent blue emitters
*Small molecules vs dendrimers and polymers
*Scientific progress vs commercial requirements
Part 2: Improved EL Efficiency of Phosphorescent OLEDs at Ultrahigh Current Densities for Lighting Applications
Dr Zang Faxin, Division of Physics and Applied Physics, School of Physical & Mathematical Science, NTU
The phosphorescent organic light emitting devices are limited by the reduced efficiency at high current densities and high brightness for white lighting, laser applications. The efficiency reducing is caused by
Multi-quenching process such as T-T or T-P quenching of long lifetime triplet excitons of Phosphorescent materials. Different quenching processes will also result in CIE changing in multi-emissive centers system at different current densities. The reduced efficiency can be overcome by using a high-performance Ir(ppy)3-based phosphorescent organic light emitting diodes, the device exhibits high current efficiency (21cd/A) at high brightness (80 000 cd/m2), with a maximum luminescence of 136 000 cd/m2 at over 1 A/m2 with an efficiency of 13 cd/A, which is higher than reference devices and related reports. This high-performance shows potential lighting or laser applications by using Phosphorescent OLED. A device physical mechanism is also discussed for better understanding of dynamic quenching process.
About the Speakers
Professor Poopathy Kathirgamanathan is a renowned expert in Organic Electronics. After attaining his PhD at Exeter, he pioneered research and development in the area of Organic Electronics at Newcastle University, Cookson Group plc., University College, London and London South Bank University (Chair in Electronic Materials Engineering since 1993). In 2000, he founded OLED-T Ltd., based on the technology that he developed at London South Bank University and served as the CTO of OLED-T until it was sold to Merck Chemicals, in August 2008. He moved to Brunel University as Professor of Electronic Materials Engineering in March 2009 where he is leading the Organic, Plastic and Printed Electronics Group, developing new materials for OLED’s, OPV and OTFT in addition to electrochemistry and nanotechnology. He is passionate about the commercialisation of OLED’s for displays and lighting. He has over 200 publications and patents and over 100 conference papers. He is also an Executive Committee Member of the Materials Chemistry Group, Society of Chemical Industries, London.
Dr Zang Faxin attained his PhD from Chinese Academy of Sciences (CAS) in 2004 after completing his Post-doctoral in Photonics Polymer Lab & Alan Heeger center of Gwangju Institute of Science and Technology (GIST) South Korea. His research interests include OLED, OPV, organic infrared emissive materials and organic spintronics. He is a research staff in the Division of Physics and Applied Physics, School of Physical & Mathematical Science, Nanyang Technological University. His current research focuses on transient behaviors of organic solar cell and the QD-LEDs works. He has published over 10 papers with a Co-PI funding.
9.15am Lecture by Prof P Kathirgamanathan
10.15am Presentation by Dr Zang Faxin
11.15am Lab Demo Session: SIMTech Vapour Deposition System for Fabrication of Organic Thin Film Devices
Who Should Attend
Researchers, engineering students, industry professionals including engineers, managers and technical staff from organic electronics related industries.
Registration for the seminar is free of charge. Seats are available on a first-come, first-served basis.
Technical enquiries: Mr Huang Zhaohong, Email: zhhuang
General enquiries: Alice Koh, Email: alicekoh@SIMTech.a-star.edu.sg