Efficient Improvement of Fluorescence Quantum Yield of Fluoreneethynylene‐Based Polymers by Introducing a Perfluoroalkylbenzene Unit to the Polymers

Abstract

AbstractIn comparison with poly(9,9‐dialkylfluorene)s widely used in organic optoelectronic devices, poly(9,9‐dialkylfluoreneethynylene)s (PFEs) have attracted less attention partly because of their poor fluorescence quantum yield (FQY) in the solid state. In order to improve the FQY, a 1,4‐bis(perfluorohexyl)benzene (BFB) unit was introduced to PFEs, and the results showed that the absolute FQY in the solid state was dependent on the mol‐% of the BFB unit in the copolymers. When mol‐% was 40 and 50%, respectively, the absolute FQY had greatly increased from 4.9% of PFE to 7.8 and 17.4% of the copolymers, respectively. For comparison, a 1,4‐dihexylbenzene (DHB) unit was also introduced to PFE, whereas the obtained copolymer showed the absolute FQY of 3.8%, suggesting that the DHB unit was not suitable for improvement of the FQY of PFEs. Electrochemically, the PFE containing BFB units showed lower reduction potential than that of PFE. All the fluorine‐containing polymers have good thermal stability.magnified image