ESPRC-JSPS Core-to-Core Grant Application

The Center for Organic Photonics and Electronics Research at Kyushu University (OPERA) recently achieved the creation of materials exhibiting highly efficient thermally activated delayed fluorescence (TADF). The new materials, based on relatively simple aromatic organic compounds, can efficiently convert triplet excitons into singlet excitons and are quickly finding application in photonic devices such as organic light-emitting diodes (OLEDs). From a fundamental photochemistry
and photophysics point of view, deeper understanding of this unique mechanism for highly efficient intersystem crossing without the need for rare metals is strongly desired.

Through this research program, cooperative research with Prof. IDW Samuel, who has expertise including ultrafast spectroscopy, Prof GA Turnbull, who has expertise in organic lasers and chemical sensors, Prof MC Gather, whose expertise includes molecular orientation, light outcoupling efficiency and use of OLEDs for biophotonics, and Dr. E Zysman-Colman, who has expertise in the synthesis of luminophores for solid-state lighting (including TADF emitters), of the University of St. Andrews (with support from EPSRC) and Prof. H Yersin of the University of Regensburg, who has expertise in organometallic TADF emitters (with support from BMBF) will be undertaken. The groups of Dr. Fabrice Mathevet (UPMC, France) with support from the CNRS and Prof. Ebinazar Namdas (University of Queensland, Australia) with support from the Australian Research Council will also be integrated into the international consortium investigating TADF emitters. This cooperative research program will focus on basic research of molecular design based on quantum chemical calculations and ultrafast photophysics analysis while also tackling device development and analysis. Through the cooperation of physicists and chemists from Japan, the UK and Germany, knowledge of optical and device properties will feed back into molecular design, and through rapid cycles of this process, new organic-semiconductor devices will be created while also developing the human resources to drive the next generation of organic optoelectronics. To promote collaboration and deepen research discussion, monthly research meetings will be held via video conferences along with semi-annual visits by researchers to participating organizations. (2) Each year, a research workshop will be held, with the three participating countries rotating as host each year, and around 10 researchers from each country will gather for a lively research discussion. (3) Moreover, the exchange of people and ideas will proceed through the sending of researchers (graduate students, post-docs, and/or assistant professors) to the participating organizations for periods of 3 to 6 months.

Furthermore, OPERA, through its connections with Fukuoka prefecture and city and its proximity to Kyushu University campus, has planned collaborations with i3-OPERA (a center for the development of organic optoelectronics for practical applications) and ISIT (The Institute of Systems, Information Technologies and Nanotechnologies) and is advancing research ranging from basic to applied with an organic optoelectronics development team formed through industrygovernment-
academia collaborations. This program will at the same time help to establish these organizations internationally, with Kyushu University at the center. In addition to the mentioned cooperative research, with regards to realizing devices, investigations into solution processing, which is highly desired, and the control of the orientation of TADF molecules will be performed. Moreover, the use of TADF for light amplification and in brand new applications will be explored, and the future possibility for electrically-pumped organic-semiconductor lasers and TADF-based photocatalysts unlocked.

Academic and industrial researchers working in the area of OLEDs, and more widely in the lighting and display sectors, will derive immediate benefit from this work. As this technology has the potential to revolutionize lighting and displays through the use of cheap, energy-efficient and environmentally benign emitters, society as whole will reap important benefits as well. Evidently, the PDRAs supported on this project will also benefit tangibly from a unique and multinational training
environment.

Already in the UK there is a well-developed community of industry in the area of solid-state lighting. These include companies such as Thorn Lighting (lighting design), Cambridge Display Technology (emissive materials), Pilkington Glass and Dupont Teijin Films (substrates) and CTI (electrodes). These companies currently rely on first- or second generation lighting materials for their devices. Commercial success in solid-state lighting relies on the use of cheap, stable and bright materials, which through this grant we propose to make. The incorporation of these materials into next-generation OLEDs will lead to important reductions in manufacturing costs in this rapidly emerging high-technology sector. This grant will also permit the UK to maintain its position as a leader in the area of solid-state lighting.

According to the US Department of Energy, 1/3 of commercial electricity use and 10% of household electricity consumption in the United States alone is dedicated towards artificial lighting. Worldwide, 20% of energy output is linked to lighting, which corresponds to 7% of global CO2 emissions. The UK is committed to an 80% reduction in greenhouse gas emissions by 2050 relative to 1990 levels. These targets can be realized through the wide-scale adoption of energy-efficient technologies, such as the proposed energy-efficient lighting an displays that are the primary targets of this grant.