Synthesis of Conjugated Copolymer Containing Spirobifluorene Skeleton by Acyclic Diene Metathesis Polymerization for Polymer Light‐Emitting Diode Applications

Grubbs‐type, Hoveyda‐type, cyclic alkyl amino carbene (CAAC)‐based ruthenium olefin metathesis catalysts were used for the acyclic diene metathesis (ADMET) polymerization of 2,7‐divinyl‐9,9‐di‐n‐octylfluorene (DVF). Additionally, various ratios of DVF and 2,2′,7,7′‐tetravinyl‐9,9′‐spirobifluorene (TVSF) were subjected to ADMET polymerization to obtain polymers P1–P7. Polymers P1–P4 were analyzed with gel permeation chromatography, UV–vis spectroscopy, and photoluminescence spectroscopy. As the TVSF ratio increases, polymers exhibit lower solubility but a narrower band in the photoluminescence spectrum. Polymer light‐emitting diode (PLED) devices were fabricated with polymers P1, P2, and P3. The performances of the PLED devices indicated that polymers including more spirobifluorene blocks showed better turn‐on voltage, brightness, current efficiency, and power efficiency. We report the activity of various types of ruthenium catalysts for acyclic diene metathesis (ADMET) polymerization. Additionally, we describe the synthesis of copolymers by ADMET copolymerization with divinylfluorene and tetravinylspirobifluorene. Polymers were analyzed for their physical and optical properties, and polymer light‐emitting diode devices were fabricated. We were pleased to find that the more the spirobifluorene blocks were included, the better was the performance of the device.