Purely Organic Blue Room‐Temperature Phosphorescence Activated by Acrylamide In Situ Photopolymerization

Abstract Purely organic room‐temperature phosphorescence (RTP), especially blue phosphorescence, has aroused considerable attention in organic optoelectronic applications. Herein, a purely solid supramolecular assembly with blue phosphorescence is constructed by 6‐bromoisoquinoline‐modified β‐cyclodextrin ( CD‐IQ ), acrylamide (AAm), and cucurbit[7]uril (CB[7]) based on in situ photopolymerization strategy, accompanied by blue RTP emission at 450 nm. The abundant hydrogen‐bonding network between the formed polyacrylamide matrix and the β‐CD effectively restricts the motion of the 6‐bromoisoquinoline chromophore and suppresses the nonradiative transition, realizing purely blue RTP emission. As compared with CD‐IQ ‐polymer, supramolecular assembly between CB[7] and CD‐IQ can improve the quantum yield and lifetime from the initial 25.5% and 238.47 ms to 49.41% and 268.9 ms, respectively, which is attributed to the confinement effect of the cucurbituril hydrophobic cavity, and can be further applied in fields of anti‐counterfeiting, information encryption, and writing.