Necessary and Sufficient Condition for Organic Room‐Temperature Phosphorescence from Host–Guest Doped Crystalline Systems

Controlling and predicting the long-lived room-temperature phosphorescence (RTP) from organic materials are next challenges to address for realization of new efficient RTP systems. Here, a approach is developed reach these objectives by considering host–guest doped crystals, as well-suited model systems in that they allow comprehensive understanding synergetic structural interactions between crystalline host matrices emitting guest molecules, one key parameters understand correlation solid-state organization crystal performances. Two series σ-conjugated donor/acceptor (D-σ-A) carbazole-based isomeric 1H-benzo[f]indole-based dopants designed, capable exploring wide variety conformations thanks large rotational degrees freedom provided σ-conjugation. By correlating results single-crystal X-ray diffraction analysis photoluminescence properties, necessary sufficient condition established paves way development