Design Strategies and Research Advances in 3D-Printed Organic Room-Temperature Phosphorescent Materials
Organic room-temperature phosphorescent (RTP) materials exhibit large Stokes shifts, high signal-to-noise ratios, and long emission lifetimes, positioning them as promising candidates for advanced anti-counterfeiting, bioimaging, sensing, and display technologies. Despite significant progress in molecular design—including radical-based systems, crystal engineering, host-guest doping, polymer matrix confinement, and supramolecular assembly—the integration of these materials with 3D printing remains in its infancy. This review critically examines the design strategies and research advances in 3D-printed organic RTP materials, focusing on the fundamental photophysical processes of intersystem crossing and suppression of non-radiative transitions. We analyze how printing parameters, matrix rheology, and layer-by-layer deposition influence phosphorescence quantum yields and lifetimes. Key challenges such as oxygen quenching, thermal degradation during extrusion, and poor interlayer adhesion are discussed with quantitative benchmarks. The review highlights that current 3D-printed RTP systems achieve lifetimes up to 1.2 s and quantum yields of 12% under ambient conditions, but scalability beyond 100 cm² remains limited by nozzle clogging and slow curing kinetics. By mapping material formulation to printability, we identify operational windows for extrusion-based and vat photopolymerization techniques. This work provides a roadmap for engineers to transition RTP materials from laboratory-scale demonstrations to industrial fabrication of complex 3D architectures with persistent luminescence.