Exploring the Scope of Through-Space Charge-Transfer Thermally Activated Delayed Fluorescence in Acrylic Donor–Acceptor Copolymers

Abstract

A series of acrylic donor and acceptor monomers were prepared to investigate the effect of electronic and structural changes on the through-space charge-transfer (TSCT) thermally activated delayed fluorescence (TADF) phenomenon. Donor (D) and acceptor (A) monomers were copolymerized using a Cu(0) reversible-deactivation radical polymerization (RDRP) approach, resulting in nonconjugated polymers with molecular weights between 8 and 21 kDa and dispersities below 1.3. Many of the resulting polymers were found to exhibit TSCT TADF, while in several cases, phosphorescence appeared to dominate. Aggregation-induced emission was also observed in many cases, consistent with a TSCT mechanism requiring close D–A contact. The results indicate that the propensity for TSCT TADF of a given D–A pair cannot be predicted solely based on the value of the singlet–triplet energy gap (ΔEST) or the frontier orbitals of the monomers and that steric considerations are likely critical for efficient TSCT.