Researchers from the University of Manchester, University of Cambridge and University of Eastern Finland, led by Dr. Alexander Romanov have developed a new deep-blue Carbene-Metal-Amide (CMA) OLED emitter material with promising operating lifetime.
The emitter is based on a a new CMA complex with a rigid amide donor, benzoguanidine. The researcher say that the new design unlocks bright charge-transfer deep-blue emission with 100% photoluminescence quantum yields. The excited state lifetimes of the new CMA complexes are among the lowest reported to date among all TADF emitters
(down to 213 ns), resulting in remarkably fast radiative rates of up to 4.7 × 10 6 s−1 .
Thanks to high thermal and photo stabilities, the materials result in impressive deep-blue OLEDs with external quantum efficiencies of up to 23% at 100 nits with color coordinates CIE (x; y) = 0.16; 0.07 and 0.17; 0.18 and device lifetimes of LT 50 = 1 hour. These results represent a sixfold increase compared with the previous best blue CMA materials thus indicating that OLED device lifetimes are correlated with the excited state lifetime of the deep-blue emitter material.
The researchers aim to further research these CMA materials and design new materials with enhanced performance.
