Lee Jihyun, Shin Dong Jin, Jo Unhyeok, Lee Jun Yeob
School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Republic of Korea.
SKKU Institute of Energy Science and Technology, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 16419, Republic of Korea.
ACS Appl Mater Interfaces. 2024 Aug 21;16(33):43786-43794. doi: 10.1021/acsami.4c09057. Epub 2024 Aug 6.
In designing thermally activated delayed fluorescence (TADF) emitters, a high reverse intersystem crossing (RISC) rate with a high photoluminescence quantum yield is essential. Herein, two blue TADF molecules, 2',5'-di(9-carbazol-9-yl)-3',6'-bis(3,6-di-butyl-9-carbazol-9-yl)-[1,1':4',1″-terphenyl]-4,4″-dicarbonitrile (CzTCzPhBN) and 2',5'-bis(3,6-di-butyl-9-carbazol-9-yl)-3',6'-bis(3,6-diphenyl-9-carbazol-9-yl)-[1,1':4',1″-terphenyl]-4,4″-dicarbonitrile (PhCzTCzPhBN) with a high RISC rate, were developed through donor engineering. CzTCzPhBN and PhCzTCzPhBN showed a high RISC rate of 4.00 × 10 and 16.62 × 10 s, respectively, with a high photoluminescence quantum yield of 80.1 and 84.9%, which resulted in high external quantum efficiency of 27.0 and 27.8% with color coordinates (0.148, 0.170) and (0.150, 0.230) in blue TADF organic light-emitting diodes, respectively. The high RISC rate and device efficiency inspired two TADF molecules to be used as sensitizers in hyperfluorescence devices. The hyperfluorescence devices showed ultra-high external quantum efficiency of 30.7 and 36.4% with color coordinates (0.125, 0.164) and (0.127, 0.193), respectively.
在设计热激活延迟荧光（TADF）发光体时，具有高光致发光量子产率的高反向系间窜越（RISC）速率至关重要。在此，通过给体工程开发了两种具有高RISC速率的蓝色TADF分子，即2'，5'-二（9-咔唑-9-基）-3'，6'-双（3，6-二丁基-9-咔唑-9-基）-[1，1':4'，1″-三联苯]-4，4″-二甲腈（CzTCzPhBN）和2'，5'-双（3，6-二丁基-9-咔唑-9-基）-3'，6'-双（3，6-二苯基-9-咔唑-9-基）-[1，1':4'，1″-三联苯]-4，4″-二甲腈（PhCzTCzPhBN）。CzTCzPhBN和PhCzTCzPhBN分别显示出4.00×10和16.62×10 s的高RISC速率，以及80.1%和84.9%的高光致发光量子产率，这使得蓝色TADF有机发光二极管的外量子效率分别高达27.0%和27.8%，色坐标分别为（0.148，0.170）和（0.150，0.230）。高RISC速率和器件效率促使这两种TADF分子被用作超荧光器件中的敏化剂。超荧光器件分别显示出30.7%和36.4%的超高外量子效率，色坐标分别为（0.125，0.164)和(0.127，0.193)。
