Blue to Yellow Thermally Activated Delayed Fluorescence with Quantum Yields near Unity in Acrylic Polymers Based on D−π–A Pyrimidines
Alexander M. Polgar, Jade Poisson, Nathan R. Paisley, Cheyenne J. Christopherson, Annelie C. Reyes, Zachary M. Hudson
Abstract
A series of acrylic monomers exhibiting bright and tunable thermally activated delayed fluorescence was synthesized based on a D−π–A design with a pyrimidine acceptor and heterocyclic amine donors. Cu(0) reversible deactivation radical polymerization of these monomers in a phenylcarbazole-based host yielded random copolymers with emission quantum yields up to 0.98 in thin films and short delayed fluorescence lifetimes as low as 2.5 μs. In all cases, monomer conversions of >95% were achieved with dispersities as low as 1.14. Kinetic studies of the polymerizations revealed differences in the rates at which host and emitter monomers react, leading to either homogeneous or gradient random copolymers, depending on the nature of the electronic donor moiety. The results indicate a complex interplay between the electronic influence of the donors on the photophysical properties and their steric involvement in polymerization, which may influence their performance in optoelectronic devices.