Enhanced proportion of radiative excitons in non-doped electro-fluorescence generated from an imidazole derivative with an orthogonal donor–acceptor structure

A greatly enhanced proportion of radiative excitons in non-doped blue electroluminescence with a maximum exciton utilizing efficiency (EUE) of 85% is harvested in the orthogonal cyano substituted, charge transfer (CT) emitter TPMCN, in comparison to the localized emission (LE)-like emitter TPM with a low EUE of 16%.