t-Bu-n-DABNA (CAS number 2914070-28-1) is a derivative of n-DABNA with two extra bulky tert-butyl groups. This material has two boron and six nitrogen atoms which knit 13 phenyl rings together to form a network of triphenylborons and triphenylamines. Two tert-butyl groups sit on the 4-positions of the phenyl rings as part of the two central triphenylamines. The introduction of these groups can effectively increase the intermolecular distance to reduce the unnecessary Dexter energy transfer (DET) and increase the PLQY by reducing the aggregation-caused self-quenching.
Demonstrating atomically separated frontier molecular orbital (FMO) distributions, the HOMO energy is located mainly on nitrogen atoms and LUMO located primarily on boron atoms. An extremely narrow emission with full width at half maximum (FWHM) of 14 nm at 467 nmis observed for the photoluminescence of t-Bu-n-DABNA in toluene. 5% doping concentration in dibenzo[b,d]furan-2,8-diylbis(diphenylphosphine oxide) (PPF) exhibits enhanced PLQY value of 91.9%.
A pure blue hyperfluorescent device, with mMDBA-DI as a TADF sensitized host and t-Bu-n-DABNA as a fluorescence emitter, exhibits a high external quantum efficiency (EQE) of 40.7%, along with narrow emission with full width at half maximum (FWHM) of 19 nm (CIE y=0.15).