Hydrogen-Bonded Supramolecular Network Triggers High-Efficiency Blue Room-Temperature Phosphorescence

Hydrogen bonding has been employed to suppress non-radiative decay in organic compounds that show room temperature phosphorescence (RTP); however, the small number of structurally diverse examples makes it unclear how general is this a strategy to turn on RTP. In this study, we report highly efficient blue RTP from 4,4',4''-nitrilotribenzoic acid (TPA-CO2H) in five structurally and chemically distinct hydrogen-bonded supramolecular networks. In doped films in polyvinyl alcohol (PVA) the phosphorescence quantum yield and lifetime (Ph and Ph) reach a PLQY 52% and lifetime of 275 ms. Boric acid also can be used to turn on RTP, and the performance changes significantly with the sample is heated beyond the dehydration temperature of this host where there is a 14-fold enhancement in the Ph after heat treatment. Blue RTP similar to that observed in PVA was also observed using granulated sugar, gelatine and paper has host matrices. We demonstrated how the emission color could be tuned by co-doping the films with Rhodamine 6G. This work elucidates for the first time the role and the generality of hydrogen bonding in activating efficient blue RTP in an organic guest containing no heavy atoms.