Accessing a Long‐Fluorescence‐Lifetime BODIPY Dye via Efficient Förster Resonance Energy Transfer Induced by Host‐Guest Doping

Abstract The development of pure organic room temperature phosphorescence (RTP) luminophores with high quantum yield and long emission lifetime has attracted considerable attention due to their extensive optoelectronic and biomedical applications. The commonly used BODIPY dyes have strong UV‐Vis absorption, a relatively sharp emission peak, high quantum yield, and a short emission lifetime. By expending the molecular doping approach, we herein successfully achieved a long‐fluorescence‐lifetime BODIPY dye via efficient Förster resonance energy transfer (FRET) from RTP molecule o ‐AI‐Cz to the short‐lived fluorescence emitter Bodipy‐2I . This host‐guest material possessed an ultralong lifetime of up to 595 ms and a long emission wavelength under ambient conditions, which has great potential in data encryption and anti‐counterfeiting applications. Moreover, this easily prepared FRET system exhibited an efficient response to two‐photon excitation in living cell fluorescence imaging.