Achieving Dual RTP/TADF Emission in a Bromine-Free 3D Ag(I) Coordination Polymer for High-Efficiency Exciton Utilization

Achieving simultaneous room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) in a single material remains a formidable challenge due to the competing nature of intersystem crossing (ISC) and reverse intersystem crossing (RISC). Herein, we report two Ag(I) coordination polymers (CPs): a bromine-free 3D framework, [Ag2(BT)(NO3)2]n (CP1), and a brominated 1D chain, [Ag2(DBBT)2(NO3)2]n (CP2). Structural and photophysical analyses reveal that CP1 exhibits dual RTP/TADF emission with a high photoluminescence quantum yield (PLQY) of 33.6%, whereas CP2 shows only RTP with a low PLQY of 3.7%. The rigid 3D architecture and absence of heavy atoms in CP1 facilitate both ISC and RISC processes, enabling efficient exciton utilization. Furthermore, CP1 demonstrates potential as a temperature-sensitive sensor and a stable luminescent ink for 3D printing. This work highlights a bromine-free structural design strategy for achieving synergistic RTP and TADF emissions in Ag(I) CPs.