New Concept for HLCT Emitter: Acceptor Molecule in Exciplex System for Highly Efficient and Extremely Low-Efficiency Roll-Off Solution-Processed OLED
The use of hybridized local and charge-transfer (HLCT) emitters as acceptor or donor molecules in exciplex systems is still a novel concept even though HLCT molecules can harvest both singlet and triplet excitons. Herein, two HLCT emitters, 2- t BuspoCz-2pTrz and 2- t BuspoCz-Me3pTrz, are prepared a...
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Published in | ACS materials letters Vol. 6; no. 10; pp. 4738 - 4747 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
American Chemical Society
07.10.2024
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Online Access | Get full text |
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Summary: | The use of hybridized local and charge-transfer (HLCT) emitters as acceptor or donor molecules in exciplex systems is still a novel concept even though HLCT molecules can harvest both singlet and triplet excitons. Herein, two HLCT emitters, 2- t BuspoCz-2pTrz and 2- t BuspoCz-Me3pTrz, are prepared as acceptors of exciplexes with thermally activated delayed fluorescence (TADF) properties. The exciplex TADF systems constructed by mixing HLCT and TAPC molecules have a minute energy gap between singlet and triplet excited states and unity emission efficiency. Using the exciplex as an emitter, solution-processed devices achieve maximum external quantum efficiency (EQE max) of 16.6%. Impressively, solution-processed devices with the fabricated exciplexes as hosts exhibit extremely low turn-on voltages and a promising EQE max of >20%, which is concomitant with an extremely low-efficiency roll-off of 0.5% at 1,000 cd m–2. This study explores the potential of HLCT emitters as acceptors of exciplexes and guides the design of efficient exciplex systems. |
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ISSN: | 2639-4979 2639-4979 |
DOI: | 10.1021/acsmaterialslett.4c01643 |