Tunable Intramolecular Charge Transfer Effect on Diphenylpyrazine‐Based Linear Derivatives and Their Expected Performance in Blue Emitters

High efficiency deep‐blue emitters are one of the basic requests for an outstanding full‐color organic light emitting diode (OLED) display. Herein, a linear D‐A‐D diphenylpyrazine structure is designed for maximizing the π‐conjugation effect, whilst two deep‐blue (DPP‐DPhC and DPP‐D3C) and one blue (DPP‐DTPA) fluorophores are synthesized by incorporating the N‐phenylcarbazole and triphenylamine donor units, respectively. As a result, they emit bright deep‐blue to blue fluorescence with the luminescence quantum yields of 0.312–0.888 in solid state. Fortunately, all the non‐doped and doped OLED devices show deep‐blue (N‐phenylcarbazole disubstituted compounds, DPP‐DPhC and DPP‐D3C) and blue (triphenylamine derivative, DPP‐DTPA) electroluminescence (EL) performance with the maximum external quantum efficiencies (EQEs) of >4%. Comprehensively considering other parameters, the deep‐blue non‐doped OLED device based on DPP‐DPhC exhibits the best EL performance with the maximum EQE of 5.73% with the Commission International de L'Eclairage (CIEx,y) coordinate of (0.151, 0.078) among them. These results demonstrate the feasibility of this strategy and provide a simple method to achieve high efficiency deep‐blue emitters.