Mes3DiKTa is a greenish blue MR-TADF emitter featuring three trimesityl groups attached to a quinolino[3,2,1-de]acridine-5,9-dione core. The steric effect imposed by the three trimesityl groups prevents aggregation-caused quenching even at high doping concentrations. Mes3DiKTa in film while doped in mCP at a concentration of 3.5 wt.% shows an improved photoluminescence quantum yield of 80% compared to 75% for the core structure DiKTa. Despite a relatively large singlet-triplet energy gap (ΔEST ≈ 0.21 eV) ), both Mes3DiKTa and DiKTa, triplets are almost quantitatively upconverted into singlets in electroluminescence. OLED device based on Mes3DiKTa as the emitter shows an EQEmax of 21.1% at 25 cd m-2 with electroluminescence of 480 nm and a narrow FWHM of 36 nm.
Also, MR-TADF emitter Mes3DiKTa can be employed as photocatalyst to give comparable or even superior productivity than the benchmark TADF green emitter and photocatalyst 4CzIPN in a wide range of photocatalytic reactions with long-lived excited states and high absorptivity.
MR-TADF red emitter 3DPA-DiKTa and green emitter 3TPA-DiKTa are also available.
* Sublimation is a technique used to obtain ultra pure-grade chemicals, see sublimed materials for OLED devices.