Thermally Driven Amorphous-Crystalline Phase Transition of Carbonized Polymer Dots for Multicolor Room-Temperature Phosphorescence

摘要

Multicolor carbon dot (CD)-based nanomaterials offer a variety of opportunities for potential applications in bioimaging, optoelectronic devices, and information security. However, it still remains a challenge to modulate the conjugated pi-structure of CDs to achieve multicolor room-temperature phosphorescence (RTP). Herein, the authors present a strategy based on thermally driven amorphous-crystalline phase transition to achieve multicolor carbonized polymer dots (CPDs) with the emission color tunable from green to orange-red. This is the first report on multicolor RTP emission from CDs by means of thermal stimulus. Further investigations reveal that the formation of self-protective covalently crosslinked frameworks and codoping of multiple heteroatoms play a crucial role in the production of RTP. RTP color tunability can be attributed to different crystalline contents of the conjugated pi-domain within CPDs. Potential application of the developed CPDs as printable and writable security inks for advanced multilevel anti-counterfeiting and encryption is demonstrated. This work paves a path for the development of multicolor RTP materials and suggests great potential of CDs in exploiting novel optical materials toward intriguing applications.