In this project we were exploring the use of exciplex based emitters with 100% efficiency through the use of thermally activated delayed fluorescence (TADF) in OLEDs.
A group of 15 PhD students were recruited and they were responsible for design and synthesis of new organic molecules, the analysis of the synthesised compounds and, finally, for the fabrication and characterisation of OLED devices. While the analysis of exciplex behaviour of commercially available compounds has been performed, the search for new efficient exciplex sets based on novel molecules advanced simultaneously.
The first 5 PhD students were successfully working on synthesis of several new compounds based on triazine, tetrazine, naphthalene imide etc. based compounds. Another 4 PhD students were working on electrochemical, spectroscopic and photophysical characterisation of commercially available and newly synthesised compounds for exciplex applications. The remaining 6 PhD students were working on different approaches in using exciplexes as efficient emitters. This included tasks ranging from stability optimisation, white device formation, and the formation of large area devices up to using printing, spin coating solution deposition process or (new in this area) organic vapour deposition processes.
There were several important results achieved during the project implementation such as setting up a new impedance technique to analyse charge carriers in OLED devices, an OLED lifetime measuring system and the formation of fully TADF exciplex based white OLED devices. In the end the main results was to present the description how to understand and optimize the exciplex emitters in order to obtain highly efficient exciplex based TADF OLED devices. All of these results bring us closer to fabrication of efficient OLED lighting devices.
