Boron subphthalocyanine polymers: Avoiding the small molecule side product and exploring their use in organic light‐emitting diodes

In this study, we set out the steps to efficiently synthesize boron subphthalocyanine (BsubPc)‐containing polymers while circumventing the formation of a known side product. The synthesis was achieved using the post‐polymerization coupling reaction of a carboxylic acid functional prepolymer with bromo‐BsubPc. We have earlier shown that when copolymerizing styrene and acrylic acid (AA) a significant amount of an undesired side product is formed. In this study, we have determined that this side product persisted when styrene was copolymerized with AA or n‐butyl acrylate but could be avoided when styrene was copolymerized with methacrylic acid (MAA), methyl methacrylate, or acrylonitrile. Therefore, MAA/styrene copolymer, synthesized by nitroxide‐mediated polymerization was chosen to be coupled to BsubPc. The resulting BsubPc polymer was found to have similar electrochemical properties, solution state absorption and photoluminescence characteristics when compared against a small molecule model compound although the solid‐state PL emission of the polymer was found to be excitation wavelength dependent. Finally, preliminary organic light‐emitting diodes (OLEDs) were fabricated to assess the potential role(s) of the BsubPc polymer in organic electronic devices. These OLEDs represent the first‐solution processed organic electronic devices containing BsubPc polymers as a functional material. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1996–2006