Deep-Blue Emitters with Aryl-Annulated Carbazole Analogues for Realizing High-Efficiency Solution-Processed TADF-OLEDs
발표자
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초록
내용
In this study, new deep-blue TADF emitters (BO-tCzPhICz and BO-tCzDICz) were developed by combining organoboron as an acceptor unit and aryl-annulated [3,2-a] carbazole-based tCzPhICz and tCzDICz as donor units. In solution-processed deep-blue TADF-OLEDs, the BO-tCzPhICz based device demonstrated a high EQE of 17.8% with CIE coordinates of (0.15, 0.077), while the BO-tCzDICz based device showed an EQE of 14.8% with CIE coordinates of (0.15, 0.062). The excellent performance of our deep-blue TADF emitters can be ascribed to the following reasons: (1) Introduction of tert-butyl group increases the electron donating ability, and the twisted structure between the donor and acceptor moieties produces a small ∆EST. (2) The combination of a rigid donor and acceptor structure enhances the PLQY along with a narrow emission. (3) The populated singlet exciton derived from high RISC rate constant and small ∆EST are attributed to the high EQE.