Enabling controllable time‐dependent phosphorescence in carbonized polymer dots based on chromophore excited triplet energy level modulation by ionic bonding

Time-dependent phosphorescence color (TDPC) materials are highly attractive for realizing multitiered dynamic information encryption and anti-counterfeiting. It's extremely challenging to modulate puzzle of multiple luminescence species and understand the intrinsic mechanism. Herein, we demonstrate a novel and synthesize-friendly strategy to develop a high contrast TDPC carbonized polymer dots (CPDs) with adjustable lifetime and quantum yields. The ionic bonding is introduced in self-protected CPDs to effectively tune the excited triplet energy level of chromophores, and promote the stable existence of L-aspartic (AA) with green phosphorescence at 545 nm, and alkali metal aspartates (AA-M) with red phosphorescence at 665 nm. The precise regulation for TDPC lifetime can be achieved based on heavy atom effort and crosslink-enhanced emission (CEE) effect. And, the efficient radiative energy transfer could be proven as an intrinsic mechanism for better understanding the TDPC materials. These results further expand on the fundamental principle to design high-quality TDPC materials with more flexible regulation for luminescence properties, providing a major step forward in broadening the scope of smart phosphorescence applications.