Boron-Ketoiminate-Based Polymers: Fine-Tuning of the Emission Color and Expression of Strong Emission Both in the Solution and Film States

In this research, the synthesis of boron-ketoiminate-containing polymers is reported with large molecular weights ((M) over bar (n) = 20 000) and their optical properties are examined by UV-vis absorption and photoluminescence spectrometries. It is shown that the polymers exhibit strong emission both in the solution and solid states (Phi(PL,THF) = 0.46-0.80, Phi(PL,film) = 0.13-0.38). These optical properties can be explained by a donor-acceptor interaction between the boron ketoiminate and the electron-donating comonomer such as fluorene or bithiophene. Furthermore, in the solid states, their emission colors can be successfully tuned from blue to orange by the substituents on the nitrogen atom with the difference of the steric hindrance (lambda(PL,THF) = 464-546 nm, lambda(PL,film) = 486-604 nm).