title: Synthesis of dibenzothiophene-containing ladder polysilsesquioxane as a blue phosphorescent host material.
abstract: A ladder polysilsesquioxanes with side chain of dibenzothiophene groups (BS-LPSQ) was successfully synthesized. The ladder structure of BS-LPSQ was characterized by MALDI-TOF MS, XRD, and (1)H NMR spectroscopy. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and spectroscopic analyses revealed that the BS-LPSQ has good film-forming ability, high thermal and morphological stability, and good miscibility to the dopant iridium bis(4,6-difluorophenyl)pyridinato-N,C(2)-picolinate (FIrpic), high triplet energy, and a wide bandgap. In addition, compared with the ringed polysiloxane BS-PSQ phosphorescent host material reported previously, the ladder structure of BS-LPSQ has not only a higher thermal resistance, but also could prevent molecular aggregation and effectively avoid quenching of fluorescence. Thus, the BS-LPSQ may be used as a better host for the blue-light-emitting iridium complex FIrpic. The performance of the electrophosphorescent device, based on the ladder BS-LPSQ as the active layer, is superior to that of ringed BS-PSQ and any other polyhedral oligomeric silsesquioxane (POSS)-based or polymer host materials.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, PR China.
authors.forename: Zhongjie
authors.initials: Z
authors.lastname: Ren
authors.forename: Dianming
authors.initials: D
authors.lastname: Sun
authors.forename: Huihui
authors.initials: H
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fu
authors.forename: Dongge
authors.initials: D
authors.lastname: Ma
authors.forename: Jianming
authors.initials: J
authors.lastname: Zhang
authors.forename: Shouke
authors.initials: S
authors.lastname: Yan