A twisted double donor in donor-acceptor-donor D-D-A-D-D type emitters yields multicomponent charge-transfer emission.

Complex donor arms in thermally-activated delay fluorescence (TADF) molecules can potentially provide additional options for charge-transfer (CT) emission through higher twisting disorder, leading to broader emission spectra. Here we design novel TADF emitters with double twisted donor moieties and show that a structural complication of the carbazole-based donor arms by changing the molecular structure from D-A-D to D-D-A-D-D yields a transition from a dual to a triple emission band with an additional CT emission component, providing a corresponding red shift and increasing low-energy emission contribution. The revealed relationship between increased complexity of the donor moiety and the multicomponent CT emission band in the D-A-D structures provides a clue for design of TADF emitters with extended emission spectra.