Ultralong Room Temperature Phosphorescence Emission From Gels Induced by Multiple Confinement Effects

Abstract The construction of ultra‐long room temperature phosphorescence (RTP) gels has always been a serious challenge because the dispersing medium would significantly deteriorate their rigidity, resulting in triplet excitons consumption by non‐radiative transitions. In this paper, eutectogel with ultra‐long RTP emission is successfully constructed by rebuilding the damaged rigid system with solvent exchange. Specifically, the formation of cyclic borate via the B─O click reaction between 1,3,5‐tris(4‐phenylboronic acid)benzene (TPPB) and poly(vinyl alcohol) (PVA) matrix is demonstrated to be favorable for RTP emission, with the resulting films possessing an afterglow duration of 26 s and a lifetime of up to 2.92 s. Based on this, deep eutectic solvents (DES)‐based RTP gel is successfully prepared by cyclic freezing‐thawing and solvent exchange of aqueous solution of TPPB functionalized PVA obtained by click reaction. The obtained gel exhibited an afterglow of up to 8 s and RTP lifetime of 902 ms under ambient conditions. Further analyses showed that the introduction of DES reconstructed interactions between polymer chains damaged by water and enhanced the rigidity of the system, thus promoting RTP emission.