Ultra-long room temperature phosphorescence carbon dots-based composites with high environmental stability

Room temperature phosphorescence (RTP) materials occupy an extremely important position in many applications, and how to achieve stable phosphorescent emission to the environment is still a huge challenge. In this article, citric acid (CA) derived carbon dots (CACDs) are firmly embedded in the melamine (MA)-derived crystals by covalently cross-linking way through a one-step hydrothermal method. The obtained CA-MA-3 composite has an ultra-long phosphorescence lifetime of 760 ms with an absolute quantum yield of 11.24%. The RTP should originate from the possible formation of hydrogen and covalent bonds between CACDs and MA-derived crystals. More importantly, the composite exhibits super-stable RTP emission in organic solvents and aqueous solutions with pH = 1 or 14. Because of the excellent phosphorescence capability of the CA-MA-3, it can be widely used for anti-counterfeiting security under extremely harsh conditions.