title: Solution-Processed Blue/Deep Blue and White Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) Hosted by a Polysiloxane Derivative with Pendant mCP (1,3-bis(9-carbazolyl)benzene).
abstract: The synthesis and characterization is reported of an efficient polysiloxane derivative containing the 1,3-bis(9-carbazolyl)benzene (mCP) moiety as a pendant unit on the polysiloxane backbone. In comparison with mCP, the mCP-polysiloxane hybrid (PmCPSi) has significantly improved thermal and morphological stabilities with a high decomposition temperature (Td = 523 °C) and glass transition temperature (Tg = 194 °C). The silicon-oxygen linkage of PmCPSi prevents intermolecular π-stacking and ensures a high triplet energy level (ET = 3.0 eV). Using PmCPSi as a host, blue phosphorescent organic light emitting devices (PhOLEDs) effectively confine triplet excitons, with efficient energy transfer to the guest emitter and a relatively low turn-on voltage of 5.8 V. A maximum external quantum efficiency of 9.24% and maximum current efficiency of 18.93 cd/A are obtained. These values are higher than for directly analogous poly(vinylcarbazole) (PVK) based devices (6.76%, 12.29 cd/A). Good color stability over a range of operating voltages is observed. A two-component "warm-white" device with a maximum current efficiency of 10.4 cd/A is obtained using a blend of blue and orange phosphorescent emitters as dopants in PmCPSi host. These results demonstrate that well-designed polysiloxane derivatives are highly efficient hosts suitable for low-cost solution-processed PhOLEDs.
authors: Dianming
authors: D
authors: Sun
authors: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, China.
authors: Xiaokang
authors: X
authors: Zhou
authors: Junteng
authors: J
authors: Liu
authors: Xiaoli
authors: X
authors: Sun
authors: Huihui
authors: H
authors: Li
authors: Zhongjie
authors: Z
authors: Ren
authors: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, China.
authors: Dongge
authors: D
authors: Ma
authors: Department of Chemistry, University of Durham , Durham DH1 3LE, United Kingdom.
authors: Martin R
authors: MR
authors: Bryce
authors: Shouke
authors: S
authors: Yan
keywords: FIrpic; high triplet energy; orange phosphor; phosphorescent organic light-emitting diode; polymeric host; polysiloxane