Combinatorial discovery of small molecule-doped afterglow polymer composites for anti-counterfeiting

The exploration of afterglow in small molecule-doped polymer composites, rooted in a nuanced understanding of structure-properties relationships, holds paramount importance for optoelectronics. However, conventional strategies face challenges in achieving high-throughput discovery of these polymers. This study introduces a novel combinatorial approach, employing photoinitiated solvent-free polymerization, to craft afterglow aromatic boronic acid-doped polymer composites. The afterglow activation results from stabilizing the triplet states of doped small molecules through a synergy of chemical and physical fixation effects. Aromatic boronic acids emerge as crucial dopants, exhibiting versatility in afterglow development across the visible spectrum. Notably, the influence of functional groups and the number of non-fused benzene rings on afterglow wavelengths is minimal, while significantly impacting afterglow lifetimes. Besides conjugation degrees, the optimal size and doping concentrations of dopants play a pivotal role in extending afterglow lifetimes. This strategy not only facilitates exploration of small molecule-based afterglow materials but also enables the feasible fabrication of intricate, multicolor afterglow polymeric objects via a step-polymerization strategy for anti-counterfeiting.