title: Syntheses, Photoluminescence, and Electroluminescence of a Series of Sublimable Bipolar Cationic Cuprous Complexes with Thermally Activated Delayed Fluorescence.
abstract: Three thermally activated delayed fluorescence cationic cuprous complexes [Cu(POP) (ECAF)]PF6(1, POP = bis(2-diphenylphosphinophenyl)ether, ECAF = 9,9-bis(9-ethylcarbazol-3-yl)-4,5-diazafluorene), [Cu(POP) (EHCAF)]PF6(2, EHCAF = 9,9-bis(9-ethylhexylcarbazol-3-yl)-4,5-diazafluorene), and [Cu(POP) (PCAF)]PF6(3, PCAF = 9,9-bis(9-phenylcarbazaol-3-yl)-4,5-diazafluorene) with bipolar 4,5-diazafluorene ligand substituted by bis-carbazole have been successfully prepared, and their UV absorption, photoluminescent properties, and electrochemical behaviors were investigated. At room temperature, complexes 1, 2, and 3 exhibit efficient yellowish-green emission with peak maxima of 550, 549, and 556 nm, respectively, and lifetimes of 5.7 μs. In powder states, the quantum yields (ϕPL) of 22.4% for 1, 18.5% for 2, and 20.0% for 3, respectively, are found. These metal phosphors can be vacuum-evaporated and applied in the organic light-emitting diodes (OLEDs) of indium tin oxide/poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (40 nm)/4,4',4″-tri(9-carbazoyl)triphenylamine (15 nm)/cuprous complexes (10 wt %): 1,3-bis(9-carbazolyl)benzene (30 nm)/1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene (50 nm)/LiF (0.5 nm)/Al (100 nm). Complex 1-based device D1 achieved a maximum luminance of 11 010 cd m-2, a current efficiency of 47.03 cd A-1, and an external quantum efficiency of 14.81%. The high electroluminescence efficiencies of these complexes are assumed to be due to their good thermal stabilities and capture of both singlet and triplet excitons. The research presented here provides a powerful tool toward highly efficient and cheap OLED devices.
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Fuli
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications , 9 Wenyuan Road, Nanjing 210023, P. R. China.
authors.forename: Yuqiao
authors.initials: Y
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.
authors.forename: Xulin
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Liang
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications , 9 Wenyuan Road, Nanjing 210023, P. R. China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications , 9 Wenyuan Road, Nanjing 210023, P. R. China.
authors.forename: Shufen
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Suzhi
authors.initials: S
authors.lastname: Li
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Fuqiang
authors.initials: F
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.
authors.forename: Canzhong
authors.initials: C
authors.lastname: Lu
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Guangxiu
authors.initials: G
authors.lastname: Cao
authors.affiliation: College of Chemistry and Chemical Engineering, Shangqiu Normal University , Shangqiu 476000, P. R. China.
authors.forename: Bin
authors.identifier: http://orcid.org/0000-0002-2866-1121
authors.initials: B
authors.lastname: Zhai