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6929767 
Journal Article 
Enhanced deep-red emission in donor-acceptor molecular architecture: The role of ancillary acceptor of cyanophenyl 
Shen, Yue; Tang, X; Xu, Y; Liu, H; Zhang, S; Yang, B; Ma, Y; , 
2019 
1 
Chinese Chemical Letters
ISSN: 1001-8417
EISSN: 1878-5964 
ELSEVIER SCIENCE INC 
NEW YORK 
1947-1950 
WOS:000496895800011 
Organic solid-state luminescent materials with high-efficiency deep-red emission have attracted considerable interest in recent years. Constructing donor-acceptor (D-A) type molecules has been one of most commonly used strategies to achieve deep-red emission, but it is always difficult to achieve high photoluminescence (PL) quantum yield (eta(PL)) due to forbidden charge-transfer state. Herein, we report a new D-A type molecule 4-(7-(4-(diphenylamino)phenyl)-9-oxo-9H-fluoren-2-yl)benzonitrile (TPAFOCN), deriving from donor-acceptor-donor (D-A-D) type 2,7-bis(4-(diphenylamino)phenyl)-9H-fluoren-9-one (DTPA-FO) with a fluorescence maximum of 627 nm in solids. This molecular design enables a transformation of acceptor from fluorenone (FO) itself to 4-(9-oxo-9H-fluoren-2-yl) benzonitrile (FOCN). Compared with DTPA-FO, the introduction of cyanophenyl not only shifts the emission of TPA-FOCN to deep red with a fluorescence maximum of 668 nm in solids, but also maintains the high eta(PL) of 10%. Additionally, a solution-processed non-doped organic light-emitting diode (OLED) was fabricated with TPA-FOCN as emitter. TPA-FOCN device showed a maximum luminous efficiency of 0.13 cd/A and a maximum external quantum efficiency (EQE) of 0.22% with CIE coordinates of (0.64, 0.35). This work provides a valuable strategy for the rational design of high-efficiency deep-red emission materials using cyanophenyl as an ancillary ancillary acceptor. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.