TY - JOUR
T1 - Isobenzofuranone- and Chromone-Based Blue Delayed Fluorescence Emitters with Low Efficiency Roll-Off in Organic Light-Emitting Diodes
AU - Lee, Jiyoung
AU - Aizawa, Naoya
AU - Yasuda, Takuma
N1 - Funding Information:
This work was supported in part by Grants-in-Aid from the Hoso Bunka Foundation, the KDDI Foundation, and the Canon Foundation. J.L. is grateful for financial support from the JSPS Research Fellowship for Young Scientists (No. 14J03825). The authors acknowledge the support of the Cooperative Research Program “Network Joint Research Center for Materials and Devices”.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/9/26
Y1 - 2017/9/26
N2 - Significant efforts have been devoted to the development of novel efficient blue-emitting molecules for organic light-emitting diode (OLED) applications. Blue organic emitters exhibiting thermally activated delayed fluorescence (TADF) have the potential to achieve ∼100% internal electroluminescence quantum efficiency in OLEDs. In this paper, we report a promising molecular design strategy for obtaining appropriate high singlet and triplet excited energies, short exciton lifetimes, and high quantum efficiencies in blue TADF emitters. We introduce isobenzofuranone and chromone containing a cyclic ketone or lactone moiety as effective acceptor building units to construct donor-acceptor TADF emitters. Owing to their small singlet-triplet energy splitting, properly contracted π-conjugation, and weakened intramolecular charge-transfer character, these new emitters display strong blue TADF emissions with high photoluminescence quantum yields (53-92%) and notably short TADF emission lifetimes (2.8-4.3 μs) in thin films. Blue TADF-OLEDs utilizing these emitters exhibit external electroluminescence quantum efficiencies of up to 16.2% and extremely low efficiency roll-off even at practical high luminance. The current findings open new avenues for designing practically usable high-performance blue TADF emitters with simple molecular structures.
AB - Significant efforts have been devoted to the development of novel efficient blue-emitting molecules for organic light-emitting diode (OLED) applications. Blue organic emitters exhibiting thermally activated delayed fluorescence (TADF) have the potential to achieve ∼100% internal electroluminescence quantum efficiency in OLEDs. In this paper, we report a promising molecular design strategy for obtaining appropriate high singlet and triplet excited energies, short exciton lifetimes, and high quantum efficiencies in blue TADF emitters. We introduce isobenzofuranone and chromone containing a cyclic ketone or lactone moiety as effective acceptor building units to construct donor-acceptor TADF emitters. Owing to their small singlet-triplet energy splitting, properly contracted π-conjugation, and weakened intramolecular charge-transfer character, these new emitters display strong blue TADF emissions with high photoluminescence quantum yields (53-92%) and notably short TADF emission lifetimes (2.8-4.3 μs) in thin films. Blue TADF-OLEDs utilizing these emitters exhibit external electroluminescence quantum efficiencies of up to 16.2% and extremely low efficiency roll-off even at practical high luminance. The current findings open new avenues for designing practically usable high-performance blue TADF emitters with simple molecular structures.
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U2 - 10.1021/acs.chemmater.7b03371
DO - 10.1021/acs.chemmater.7b03371
M3 - Article
AN - SCOPUS:85029949149
VL - 29
SP - 8012
EP - 8020
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 18
ER -