Separate Control Model for Tailoring Ultralong Organic Room-Temperature Phosphorescence with Highly Efficient Energy Transfer to Rhodamine B

Organic room-temperature phosphorescence (RTP) materials have attracted significant attention for their promising applications, yet achieving high-efficiency RTP molecules remains challenging. To address this, a comprehensive dataset of donor-acceptor (D-A) structured molecules is developed using D and A fragment pools. Promising phosphorescent candidates can be efficiently identified through high-throughput screening that combines density functional theory (DFT) with high-precision multireference perturbation theory calculations. A key innovation is the introduction of the "separate control model", which independently optimizes both spin-orbit coupling (SOC) and the singlet-triplet energy gap (Delta EST). Using this method, the phosphorescent unit 5,5-dioxido-10-(phenanthren-9-yl)-10H-phenothiazin-3-yl)(phenyl) methanone (PPTZO-CO), exhibits an exceptionally high intersystem crossing (ISC) rate constant of 10(1)(1) s(-)(1), representing the highest value reported in organic systems to date. Remarkably, the RTP lifetime of PPTZO-CO reaches up to 700 ms when doped into polymethyl methacrylate (PMMA). Co-doping PPTZO-CO with rhodamine B (RB) in PMMA yields red afterglow emission with near 100% energy transfer efficiency, the highest reported for co-doped polymer systems. The PPTZO-CO@PMMA system demonstrates promise in dynamic anti-counterfeiting, showcasing its potential for practical use.