Colella, Marco, Pander, Piotr Henryk
, Pereira, Daniel De Sa & Monkman, Andrew P. (2018). Interfacial TADF Exciplex as a Tool to Localise Excitons, Improve Efficiency and Increase OLED Lifetime. ACS Applied Materials & Interfaces 10
Author(s) from Durham
In this work, we employ a TADF exciplex formed between the emissive layer (EML) host, 26DCzPPy, and the electron transport layer (ETL), PO-T2T at the interface between the EML and the ETL to improve the stability and efficiency of a phosphorescence OLED based on Ir(dmpq)2acac. We show that the presence of the TADF exciplex at the EML-ETL interface induces an efficient localisation of the recombination zone which is confined within the 5 nm thick EML. Furthermore, the TADF exciplex allows harvesting of the holes and electrons that piled-up at the EML-ETL interface and transfer the resultant excited state energy to the phosphorescent emitter through Förster and/or Dexter energy transfer. This approach effectively improves the LT90 of devices from <1 min to 6 h by limiting recombination processes outside of the 5 nm EML.