Protic acids as third components improve the phosphorescence properties of the guest-host system through hydrogen bonds

Host-guest doped materials have attracted widespread attention. However, most of the doped materials are two-component systems, and the phosphorescence properties and functions need to be further improved. Herein, diphenyl sulfoxide was selected as the host, and 1,3-diphenylbenzofuro[2,3-c]pyridine was designed as the guest to construct a new phosphorescence doped system. Importantly, water, phenol, benzoic acid, and phenylboronic acid are selected as the third component to form hydrogen bonds with the host molecules, the hydrogen bonds can improve the phosphorescence performance of doped materials. The phosphorescence quantum yields are increased from 4.3 % of the two-component to 18.8% −28.5 % of the three-component, and the phosphorescence lifetimes are increased from 147 ms to 235–308 ms. Moreover, the addition of the third component makes the phosphorescence of the doped system has a reversible alkali stimulus–response function. This work provides a universal strategy for constructing the multi-component doped systems with better phosphorescence performance or more phosphorescence functions.