ICT occurs when a photoexcitation is used to cause an electron transfer between a donor and an acceptor in the same molecule. This transfer can be stabilized with an orthogonal twist. Thermally activated delayed fluorescent (TADF), which harnesses triplet excitons, uses this phenomenon.
The twisted structure of TADF molecules, however, limits the device’s lifetime. Although rigid molecules improve stability, they hinder ICT due to their planar, P-conjugated structure.
Newcastle University’s top-ranked Physics Department has developed a new method for improving the efficiency and stability of organic light emitting diodes. The breakthrough is a new type of molecule that has the ability to significantly extend the life of OLEDs.
Researchers have created a new approach for designing organic molecules to retain their stability and effectiveness over time even when under extreme stress. The new molecules are a challenge to existing theories of intramolecular charges transfer excited states. They propose a new model which links molecular bonds patterns with breaking pi-conjugation and explains this phenomenon.
The first fully 3D printed flexible OLED display
The “rigidly-planar charge transfer molecules” improve triplet extraction, thereby increasing OLED efficiency via thermally activated delay fluorescence. The new OLED molecule design is more stable than traditional OLEDs, which can twist or lose their stability. This ensures longer device life.
This new method could increase the durability of OLED displays, which would reduce their need to be replaced frequently.
Journal Reference
- Kuila, S., Miranda-Salinas, H., Eng, J. et al. The thermally-activated delayed fluorescence of intramolecular charges-transfers states is observed in rigid and planar molecules conjugated with p. Nat Commun 15, 9611 (2024). DOI: 10.1038/s41467-024-53740-1
