Abstract

The first generation OLE Ds were based on organic fluorescent emitters. Their efficiency was intrinsically capped at 25% due to only being able to recruit singlet excitons. The second generation OLE Ds have employed organometallic phosphorescent emitters, which harvest both singlet and triplet excitons for emission due to the enhanced intersystem crossing mediated by the heavy metals such as iridium(III) and platinum(II). These metal complexes possess very desirable optoelectronic properties and lead to very efficient OLED devices. However, the rarity of these metals, their high cost and their toxicity are important detracting features that inhibit large-scale, worldwide adoption of OLED technology, particularly for lighting where, unlike displays, low cost devices are crucial to market growth. The third generation OLE Ds are based on small organic compounds that emit via a thermally activated delayed fluorescence (TADF) mechanism. As with phosphorescent emitters, OLE Ds using these emitters can recruit 100% of the excitons. In this presentation, we present our recent efforts towards blue emitter in electroluminescent devices.