A team of researchers from the Faculty of Mathematics, Physics and Computer Science (dr Michał Mońka, dr hab. Illia Serdiuk, prof. Piotr Bojarski and mgr Radosław Rogowski) and the Faculty of Chemistry at the University of Gdańsk (dr Daria Grzywacz and dr hab. Artur Sikorski) in cooperation with Durham University and the Silesian University of Technology has made significant progress in OLED technology. Their latest article in the prestigious journal ASC Applied Materials & Interfaces (200 points) describes the details of the invention, which has a chance to be implemented in the so-called fourth generation of OLEDs. Dr Michał Mońka talks about the innovation.

- What is the main focus of the research that is the basis for the latest publication?

Dr Michał Mońka: - The research concerns a solution to the problem of low stability of materials responsible for the conversion of electricity into light (so-called light emitters). Such emitters are key components of Organic Light-Emitting Diode (OLED) displays, enabling the display of high-quality images that we use every day, e.g. in smartphones, laptops or televisions.

Currently, all displays using OLED technology are based on materials containing heavy metals. We want to move away from the use of expensive and toxic materials, making production cheaper, easier and more environmentally friendly. However, it has not yet been possible to develop a fully organic emitter (without heavy metals) that is stable enough.

- Have you managed to change this? What is the achievement that you present in the article?

- In the article, we present one of our latest inventions - a fully organic emitter characterised by high efficiency and stability. Thanks to application tests carried out at one of the leading research centres in the UK, we have proven that our material has a very high implementation potential and can be used in fourth-generation OLEDs. What's more, the emitter we designed, in combination with other auxiliary molecules, can create very efficient near-infrared (NIR) emission systems. In addition to their use in OLEDs, such materials are particularly important due to their wide range of applications in medicine, e.g. in non-invasive diagnostic procedures or vital signs monitoring.

- How did you manage to do this?

- The key to success was not only the creation of new material but also the understanding of the mechanisms behind its high efficiency and stability. Since 2020, we have been conducting intensive research into photophysical processes involving emitters that can increase their stability in OLEDs. These include thermally activated delayed fluorescence, the heavy atom effect and resonant energy transfer. Our work focuses on combining selected processes and specifically controlling intermolecular interactions in order to optimise their mutual contribution and (ultimately) OLED parameters.

We have established that, in addition to the chemical structure of the emitter itself, how the molecules in the material are arranged in relation to each other is equally important. In particular, the material we have developed has a clear tendency to form so-called π-stacking, i.e. a layered arrangement of molecules in which their flat fragments overlap like a stack of sheets of paper. This way, the heavy atom effect of the bromine insertion is intensified many times over, which has a positive effect on the stability of the OLED.

- What are the next steps with the invention?

- We are currently in a technology race to be the first to develop and implement a fully organic material in OLEDs. Based on the knowledge and work of the entire team, we have all the necessary prerequisites to win. Experience, purposeful ideas, know-how in the field and a rich portfolio of inventions protected by patents are our most important assets.

The main limiting factor is the scale at which we are able to operate. As a team of just a few people, we are grateful for the support of our partner research centres, as we do not have the facilities to test and produce OLEDs in-house. To accelerate the development and optimisation of our materials, we need to expand our research infrastructure and invest in the modern tools necessary for further testing and prototype production.

Therefore, we are actively looking for partners in the economic sector, business support and financing opportunities that will facilitate further research and development of the technology. We are particularly interested in collaborating with companies that manufacture OLED displays and institutions that support innovative projects.

Link to publication: Heavy Atom as a Molecular Sensor of Electronic Density: The Advanced Dimer-Type Light-Emitting System for NIR Emission | ACS Applied Materials & Interfaces

We have previously written about the team's research here.

The research was funded under the LIDER XI grant (LIDER/47/0190/L-11/19/NCBR/2020, manager: dr hab. Illia Serdiuk).