title: Solution-processed, undoped, deep-blue organic light-emitting diodes based on starburst oligofluorenes with a planar triphenylamine core.
abstract: A series of starburst oligomers (T1-T3) that contained a fully diarylmethene-bridged triphenylamine core and oligofluorene arms were designed and synthesized through Suzuki cross-coupling reactions. Their thermal, photophysical, and electrochemical properties were also investigated. These materials showed high glass transition, in the range of 123-129 °C, and good film-forming abilities. They displayed deep-blue emission both in solution and as thin films. Solution-processed devices based on these oligomers exhibited highly efficient deep-blue electroluminescence and the device performances were significantly enhanced with the extension of the oligofluorene arms. The double-layered device that contained T3 as an emitter showed a maximum current efficiency of 3.83 cd A(-1) and a maximum external quantum efficiency of 4.19% with CIE coordinates of (0.16, 0.09), which are among the highest values for undoped deep-blue OLEDs that are based on solution-processable starburst oligomers.
authors.affiliation: Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072 P.R. China.
authors.forename: Cui
authors.initials: C
authors.lastname: Liu
authors.forename: Yanhu
authors.initials: Y
authors.lastname: Li
authors.forename: Yingyue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chuluo
authors.initials: C
authors.lastname: Yang
authors.forename: Hongbin
authors.initials: H
authors.lastname: Wu
authors.forename: Jingui
authors.initials: J
authors.lastname: Qin
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao