The emissive layer of an OLED display is its most important layer, where the electric charge is combined with the organic materials and light is emitted. The emissive layer is comprised of an emitter and a host, and is the subject of intensive research and development efforts.
TADF emitters set out to solve three main challenges with current generation OLED emitters:
- Low cost and non-heavy-metal alternative to current red and green phosphorescent emitters
- Efficient and long-lasting soluble emitters suitable for ink-jet printing
- An efficient and long-lasting blue emitter
TADF molecules have a small energy gap between the singlet and the triplet energy states (⊿Est). This enables up-conversion of excited energy from triplet to singlet spin, which provides highly efficient photonic emission from the singlet energy state in the form of delayed fluorescence.