Facile one-step pyrolysis of aliphatic dicarboxylic acids toward multicolor room-temperature phosphorescent carbon dots: luminescence mechanism and dynamic information anti-counterfeiting

Room-temperature phosphorescent carbon dots (RTP-CDs) emerge as pivotal materials for bioimaging and information encryption, yet their application is hindered by complex synthesis, limited color tunability, and short lifetimes. Herein, we develop a one-step pyrolysis strategy to fabricate RTP-CD composites using aliphatic dicarboxylic acids and boric acid. Significantly, only the adipic acid-boric acid system (CDA) achieves ultrabroad multicolor RTP from blue to red (470–610 nm) with a record-high afterglow of 9 s. Chlorine modification further extends the afterglow to 16 s and elevates the phosphorescence lifetime to 43.76 ms without compromising color range. Mechanistic studies reveal that the rigid boron oxide matrix suppresses non-radiative transitions of triplet excitons, while CD size and surface oxidation govern emission color; the external heavy-atom effect reduces singlet-triplet energy gaps to enhance intersystem crossing (ISC). Leveraging time-resolved multicolor phosphorescence, we demonstrate dynamic anti-counterfeiting with color evolution and multi-dimensional Morse code encryption, offering a scalable synthesis route and novel materials for high-security applications. Download: Download high-res image (88KB) Download: Download full-size image