Asymmetric multiple resonance thermally activated delayed fluorescence emitters for sky-blue and pure blue electroluminescence

Two asymmetric MR-TADF materials, Cz-SCz and BCz-SCz, exhibit sky-blue and pure blue emission with small FWHMs of 28 and 24 nm, respectively. OLEDs display EQE max values of up to 20.5%, and that with BCz-SCz achieves pure blue emission with a CIE y coordinate below 0.15.