Solid-Phase Engineered Metal-Free Carbonized Polymer Dots With Auto-Generated Rigid Amorphous Network Enabled High-Temperature Liquid-Phase Phosphorescence.

While organic phosphorescent materials hold immense promise, their application is severely hampered by limited emission tunability, short lifetimes, and environmental instability. Herein, we report a facile solid-phase engineering strategy to achieve the large-scale synthesis of metal-free carbonized polymer dots (CPDs) from a single precursor. These CPDs feature tunable phosphorescence wavelengths (∼472 to 545 nm) and lifetimes (∼646.49 µs to 65.56 ms), coupled with extraordinary resilience to thermal and moisture stress. Experimental surveys and theoretical calculations reveal that high-temperature solid-phase reaction drive the structural evolution of CPDs from amorphous molecules to ordered heptazine structures, enabling the CPDs with progressive singlet-triplet energy splitting for tunable phosphorescence wavelengths. Concurrently, the auto-generated rigid amorphous network and hydrophobic groups of CPDs synergistically mitigate triplet exciton quenching triggered by dissolved oxygen and thermal deactivation, endowing the tunable high-temperature liquid-phase phosphorescence. With the unique optical characteristics, these CPDs show great promise for applications in aqueous-phase illumination, displays under harsh conditions, and three-dimensional information encryption. This work paves a new approach to polymeric phosphorescent materials, significantly contributing to the advanced lighting and information technologies.