Design Strategies and Research Advances in 3D-Printed Organic Room-Temperature Phosphorescent Materials

• • Current 3D-printed organic RTP materials achieve maximum phosphorescence lifetimes of 1.2 s and quantum yields of 12% under ambient conditions, but these values drop by 40–60% when printed at layer heights below 100 µm due to increased oxygen diffusion and surface quenching. • • Extrusion-based printing of RTP composites requires matrix viscosities between 10^3 and 10^5 Pa·s at shear rates of 10–100 s⁻¹ to prevent nozzle clogging; exceeding 10^5 Pa·s leads to filament fracture and a 30% reduction in interlayer adhesion strength (below 5 MPa). • • Thermal degradation during fused deposition modeling occurs at processing temperatures above 180 °C, causing a 25% loss in phosphorescence intensity for host-guest systems, necessitating the use of low-melting-point polymer matrices (e.g., polycaprolactone, Tm = 60 °C) or photopolymerization routes. • • Vat photopolymerization enables RTP feature sizes down to 50 µm with a curing time of 2–5 s per layer, but oxygen inhibition reduces the effective phosphorescence lifetime by 35% in the top 20 µm of each layer, requiring inert atmospheres or oxygen scavengers to maintain performance.