Synthesis and Electroluminescent Properties of Through-Space Charge Transfer Polymers Containing Acridan Donor and...

We report the design, synthesis and electroluminescent properties of three kinds of through-space charge transfer (TSCT) polymers consisting of non-conjugated polystyrene backbone, acridan donor and triarylboron acceptors having different substituents such as hydrogen (H), fluorine (F), and trifluoromethyl (CF₃). Owing to the weak electron interaction between acridan donor and triarylboron acceptor through non-conjugated connection, blue emission with peaks in range of 429-483 nm can be achieved for the polymers in solid-state film, accompanied with photoluminescence quantum yields of 26-53%. The resulting TSCT polymers exhibit small ΔE_ST values below 0.1 eV owing to the separated HOMO and LUMO distributions, showing thermally activated delayed fluorescence with lifetimes in range of 0.19-0.98 μs. Meanwhile, the polymers show aggregation-induced emission (AIE) effect with the emission intensity increased by up to ~33 folds from solution to aggregation state. Solution-processed organic light-emitting diodes based on the polymers containing trifluoromethyl substituent exhibit promising electroluminescent performance with maximum luminous efficiency of 20.1 cd A^-1 and maximum external quantum efficiency of 7.0%, indicating that they are good candidates for development of luminescent polymers.