Tailoring Intermolecular Interactions for Efficient Room-Temperature Phosphorescence from Purely Organic Materials in Amorphous Polymer Matrices

Herein we report a rational design strategy for tailoring intermolecular interactions to enhance room‐temperature phosphorescence from purely organic materials in amorphous matrices at ambient conditions. The built‐in strong halogen and hydrogen bonding between the newly developed phosphor G1 and the poly(vinyl alcohol) (PVA) matrix efficiently suppresses vibrational dissipation and thus enables bright room‐temperature phosphorescence (RTP) with quantum yields reaching 24 %. Furthermore, we found that modulation of the strength of halogen and hydrogen bonding in the G1–PVA system by water molecules produced unique reversible phosphorescence‐to‐fluorescence switching behavior. This unique system can be utilized as a ratiometric water sensor. A bright idea: Rationally designed strong intermolecular hydrogen and halogen bonds between a novel phosphor and a poly(vinyl alcohol) (PVA) matrix led to bright room‐temperature phosphorescence (RTP) with a quantum yield of 24 %. Modulation of the strength of halogen and hydrogen bonding in the purely organic phosphor–PVA system by water enabled reversible switching between phosphorescence (green) and fluorescence (blue).