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Diboron-Based Delayed Fluorescent Emitters with Orange-to-Red Emission and Superior Organic Light-Emitting Diode Efficiency
摘要： For the application of OLEDs in lighting and panels, the basic requirement is to include a full spectrum color range. Compared with the development of blue and green luminophores in thermally activated delayed fluorescence (TADF) technology, the progress of orange-to-red materials is slow and needs further investigation. In this study, three diboron compound-based materials, dPhADBA, dmAcDBA, and SpAcDBA, were designed and synthesized by nucleophilic arylation of three amine donors on 9,10-diboraanthracene (DBA) in a two-step reaction. With increasing electron-donating ability, they show orange-to-red emission with TADF characteristics. The electroluminescence (EL) of these diboron compounds exhibits emissions λmax at 613, 583, and 567 nm, for dPhADBA, dmAcDBA, and SpAcDBA, respectively. It is noteworthy that the rod-like D-A-D structures can achieve high horizontal ratios (84~86%) and outstanding device performance for orange-to-red TADF OLEDs: the highest external quantum efficiencies (ηEQE) for dPhADBA, dmAcDBA, and SpAcDBA are 11.1 ± 0.5%, 24.9 ± 0.5%, and 30.0 ± 0.8%, respectively. Therefore, these diboron-based molecules offer a promising avenue for the design of orange-to-red TADF emitters and the development of highly efficient orange-to-red OLEDs.
关键词： thermally activated delayed fluorescence,9,10-diboraanthracene,horizontal dipole ratio,diboron compound,orange-red color,organic light-emitting diode
更新于2025-09-23 15:19:57
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Harnessing A New Co-Host System and Low Concentration of New TADF Emitters Equipped with Trifluoromethyl and Cyano Substituted Benzene as Core for High Efficiency Blue OLEDs
摘要： A strategic approach combining a new co-host system and low concentration of new TADF emitters to make efficient blue TADF OLED was developed. The benchmark TADF molecule, 4CzIPN, was adopted as a probe to examine the feasibility of a co-host composing of a hole-transporter SimCP and an electron-transporter oCF3-T2T. As a result, a sky blue device with 1wt% 4CzIPN doped in SimCP:oCF3-T2T co-host exhibited 100% energy transfer and achieved high EQE up to 26.1%. Importantly, this device showed limited efficiency roll-off with EQE of 24% at 1000 cd m-2. To further shift the emission toward blue, three new TADF molecules, 4CzIPN-CF3, 3CzIPN-H-CF3 and 3CzIPN-CF3, modified either by lowering the electron-withdrawing ability of acceptor group or reducing the number of carbazole donors of 4CzIPN, have been synthesized and characterized. Among them, 4CzIPN-CF3 and 3CzIPN-H-CF3 display hypsochromic shift emissions as compared to that of 4CzIPN. These new compounds were then explored for their potential applications as TADF emitters. Blue TADF OLEDs with 1wt% of 4CzIPN-CF3 and 3CzIPN-H-CF3 dispersed in SimCP:oCF3-T2T co-host achieved EQE of 23.1% and 16.5%, and retained high EQE of 20.9% and 14.7% at 1000 cd m-2, respectively.
关键词： 4CzIPN,TADF emitter,co-host,horizontal dipole ratio,OLED
更新于2025-09-12 10:27:22