Deep-blue emitting poly(2′,3′,6′,7′-tetraoctyl-2,7-spirosilabifluorene) simultaneously with good color purity and high external quantum efficiency

A deep-blue emitting poly(2′,3′,6′,7′-tetraoctyl-2,7-spirosilabifluorene), namely PSSiBF, has been newly developed for PLEDs. Unlike the previously-reported alkyl-functionalized P27SiF, the unwanted aggregation can be effectively prevented in PSSiBF due to the perpendicular arrangement between two spiro-linked dibenzosilole moieties. Compared with P27SiF (ΦPL = 0.62), consequently, an improved PLQY of 0.84 is obtained for the film of PSSiBF accompanied by a significant reduction of the long-wavelength emission in the range of 450–550 nm. Based on a double-layer device configuration, PSSiBF gives a bright deep-blue electroluminescence, revealing a state-of-art EQE of 2.8% and CIE coordinates of (0.16, 0.06). The simultaneous realization of good color purity and high EQE clearly implies that the silicon-containing polymers do have the great potential in efficient PLEDs.