High Performance Organic Narrowband Emitters for Stable Blue OLEDs

Constricted by electron spin statistics, the maximum internal quantum efficiency of 100% can be achieved in organic light-emitting diodes (OLEDs) by utilizing purely organic thermally activated delayed fluorescence (TADF) materials. However, due to strong charge transfer, they exhibit broad emission with a full-width-at-half maximum (FWHM) > 70 nm.

Recently, multiresonant TADF (MR-TADF) emitters, a sub-class of TADF materials based on alternating boron and nitrogen atoms embedded into polycyclic aromatic hydrocarbon scaffolds, are attracting much interest in OLEDs. Their key attributes include a narrow FWHM, high photoluminescence quantum yield, and unprecedented color purity.

Even though these MR materials have advantages in color purity over conventional TADF materials, their device stability is weak and results in a poor operational lifetime (LT) due to the large singlet-triplet energy gap, delayed fluorescence lifetime, and too slow rate of reverse intersystem crossing (RISC).

Especially, narrowband blue OLEDs LT (