Precisely Regulating 2.45 s Pure Blue Room-Temperature Phosphorescence via Supramolecular Coordination

Achieving tunable blue room-temperature phosphorescence (BRTP) emission faces forbidden challenges due to difficulties in generating high-energy triplet excitons and their sensitivity. Herein, a covalently crosslinked purely organic material (BOP@BA) is prepared from boric acid (BA) and 3,5-dicarboxyphenylboronic acid (BOP) via a simple dehydration reaction. This material exhibits pure deep blue room-temperature phosphorescence (RTP) with a lifetime of 2.45 s. Unlike individual BA or BOP, dehydrated BOP@BA exhibits a hypsochromic shift to 415 nm, yielding a purely deep-blue RTP. Meanwhile, the formed covalent skeleton protects the high-energy triplet excitons from nonradiative deactivation, thereby elongating the lifetime to 2.45 s. Significantly, lanthanide ions (Ln³⁺: Eu³⁺ and Tb³⁺), acting as fine controllers, enable precise tuning of the lifetime through supramolecular coordination and energy transfer, with a precision of as low as 0.1 s and an effective range of 1.71-2.45 s. This work is expected to provide a feasible strategy for constructing ultralong BRTP materials and achieving precise luminescence manipulation.