HKU chemists develop a new class of robust gold(III) complexes with promising device lifetimes and tunable emission colours for vacuum-deposited OLEDs
A team of researchers led by Professor Vivian Wing-Wah Yam, Philip Wong Wilson Wong Professor in Chemistry and Energy and Chair Professor of the Department of Chemistry, has overcome the key synthetic challenges for the design of robust gold(III) complexes and demonstrated for the first time highly efficient gold(III)-based organic light-emitting devices (OLEDs) with long operational lifetimes, reaching half-lifetimes of up to 83,000 hours. The findings have been published in January in the leading scientific journal, Nature Photonics (link). Gold, a noble metal that has been widely used as currency and ornamental jewellery since ancient times and more recently in industry, has been a metal well-known for its inertness, low toxicity, and environmentally friendly and benign nature. With China having the second largest gold reserve in the world, there is a strong motivation and advantage of developing the organometallic chemistry and novel materials of gold, such as phosphorescent emitters for OLEDs. Through dedicated efforts and rational design of pincer and ancillary ligands, the team has found the right balance for the ligand coordination environment to overcome the thermal stability challenge, generating a new class of robust gold(III) complexes with tridentate C^C^N ligands. This class of gold(III) complexes demonstrates full-colour gamut spanning across the visible region from sky-blue to red with high solid-state photoluminescence quantum yields of up to 80%. These complexes are also capable of serving as phosphorescent dopants for OLEDs; notably, extraordinarily high current efficiencies of up to 72 cd A-1 and external quantum efficiencies of up to 21.6% have been achieved. More importantly, long device half-lifetimes of up to 83,000 hours have been realised in these gold(III)-based OLEDs. This is the first practical gold(III)-based OLEDs with long device lifetime. The present work holds great promise and would open up a new avenue for the development of new classes of practical phosphorescent emitters based on metal centres other than the commercially used but rare iridium(III) system, paving the way towards the possible revolutionisation of the OLED market. More information about Professor Vivian Yam.
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HKU Vice-President and Chemistry scholar Professor Andy Hor elected Fellow of the European Academy of Sciences
Professor Andy Hor, Vice President (Research) and Chair Professor of Metallic Chemistry & Materials at the University of Hong Kong (HKU), has been elected a fellow of the European Academy of Sciences (EurASc). EurASc is a non-profit, non-governmental and independent organisation established in 2003 in Brussels, aiming to promote excellence in science and technology. It awards prestigious prizes including the Leonardo da Vinci Award and the Blaise Pascal Medal. It currently has about 600 fellows, over 10% of whom are Nobel Laureate and Fields Medalists from over 40 countries. Professor Hor is honoured for his achievements and contributions to academia in the area of structural metallic chemistry. He specialises in the design, synthesis and structural analysis of novel molecules. His research lies at the fundamental of molecular science – to analyse the molecular composition and structure as a means to understand the properties and activities of a molecule or molecular materials, and from such knowledge, design new molecules, as well as develop new functions and applications. “This is how new science can be developed, translated and eventually be applied as new technologies,” said Professor Hor, who is honoured and delighted to receive the award. Professor Hor refers to the simple doctrine which has guided his research – technology is most disruptive when its science is at its (creative) root and said: “This is also how international fellowship like that from the European Academy of Science and prestigious prizes like Nobel Prize and Fields medal are conferred.” Over the years, his team has investigated a range of systems in coordination and organometallic complexes, hetero- and polynuclear aggregates and clusters, as well as metal-organic frameworks and molecular materials. These are molecular substances that form the basis of industrial chemicals, pharmaceutical catalysis as well as a range of energy and environmental applications. Recently, he has teamed up with scientists at the Agency of Science, Technology & Research (A*Star) of Singapore to study metal-air and metal-sulfide batteries as the next-generation of green batteries. Professor Hor has published over 435 international papers with an average of 1,200 annual citations in 2017-8, filed several patents in battery materials and supervised over 100 PhD, MSc and other research students. Biography of Professor Andy Hor Professor Andy Hor is the Vice President and Pro-Vice-Chancellor (Research) and Chair Professor of Metallic Chemistry & Materials of the University of Hong Kong (HKU). He started his academic career at the National University of Singapore (NUS) in which he also served as Head of Chemistry and Vice Dean (Academic) of Science. He later served as the Executive Director of the Institute of Materials Research & Engineering of the Agency of Science, Technology & Research (A*Star) of Singapore for 5 years before joining HKU in September 2015. He is Fellow of the Singapore National of Chemistry, Singapore National Academy of Science, and Royal Society of Chemistry in the UK, and former President of the Singapore National Institute of Chemistry and Federation of Asian Chemical Societies. He has contributed significantly over four decades to the development of chemistry in Singapore, Asia and the world through his research programs and various community services and leadership in international conferences and academic journals, and won numerous teaching and research awards while in NUS and A*Star. For Professor Hor’s detailed biography, please visit: https://presidentoffice.hku.hk/smt/pvc-R.html. EurASc website: http://www.eurasc.org/
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