TY - JOUR
T1 - A Series of Imidazo[1,2-f]phenanthridine-Based Sky-Blue TADF Emitters Realizing EQE of over 20%
AU - Ohsawa, Tatsuya
AU - Sasabe, Hisahiro
AU - Watanabe, Taiki
AU - Nakao, Kohei
AU - Komatsu, Ryutaro
AU - Hayashi, Yuya
AU - Hayasaka, Yuya
AU - Kido, Junji
N1 - Funding Information:
The authors greatly acknowledge the partial financial support from the Center of Innovation (COI) Program from Japan Science and Technology Agency, JST. H.S. acknowledges financial support in part by JSPS KAKENHI (17H03131) from JSPS.
Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/3/5
Y1 - 2019/3/5
N2 - Although imidazole derivatives are promising as blue fluorescent emitters in organic light-emitting devices (OLEDs), the corresponding blue thermally activated delayed fluorescence (TADF) emitter is rarely explored. In this study, a series of imidazo[1,2-f]phenanthridine-based TADF materials in the blue to sky-blue region is developed. The resultant benzimidazole (BIP)-based TADF materials, with π-expanded acceptor and electron-donor phenoxazine (PXZ), namely PXZ-BIP, shows a high maximum external quantum efficiency (η ext,max ) of 21% with CIE coordinates of (0.21, 0.37). These results have clearly demonstrated that PXZ-BIP exhibits the highest η ext,max among imidazole-based fluorescent sky-blue OLEDs. The corresponding imidazophenanthridine derivative, with a less π-expanded acceptor, shows inferior OLED performances, with a η ext,max of 5.9% and CIE of (0.19, 0.30). This study provides a critical molecular design to realize high-efficiency TADF materials based on imidazole derivatives.
AB - Although imidazole derivatives are promising as blue fluorescent emitters in organic light-emitting devices (OLEDs), the corresponding blue thermally activated delayed fluorescence (TADF) emitter is rarely explored. In this study, a series of imidazo[1,2-f]phenanthridine-based TADF materials in the blue to sky-blue region is developed. The resultant benzimidazole (BIP)-based TADF materials, with π-expanded acceptor and electron-donor phenoxazine (PXZ), namely PXZ-BIP, shows a high maximum external quantum efficiency (η ext,max ) of 21% with CIE coordinates of (0.21, 0.37). These results have clearly demonstrated that PXZ-BIP exhibits the highest η ext,max among imidazole-based fluorescent sky-blue OLEDs. The corresponding imidazophenanthridine derivative, with a less π-expanded acceptor, shows inferior OLED performances, with a η ext,max of 5.9% and CIE of (0.19, 0.30). This study provides a critical molecular design to realize high-efficiency TADF materials based on imidazole derivatives.
UR - http://www.scopus.com/inward/record.url?scp=85059350778&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85059350778&partnerID=8YFLogxK
U2 - 10.1002/adom.201801282
DO - 10.1002/adom.201801282
M3 - Article
AN - SCOPUS:85059350778
VL - 7
JO - Advanced Optical Materials
JF - Advanced Optical Materials
SN - 2195-1071
IS - 5
M1 - 1801282
ER -