Hour‐Level Persistent Multicolor Phosphorescence Enabled by Carbon Dot‐Based Nanocomposites Through a Multi‐Confinement‐Based Approach

Abstract Hour‐level persistent room temperature phosphorescence (RTP) phenomena based on multi‐confinement carbon dots (CDs) are reported. The CDs‐based system reported here (named Si‐CDs@B 2 O 3 ) can be efficiently synthesized by a simple pyrolysis method compared to the established persistent RTP systems. The binding modes of CDs, silica (SiO 2 ), and boron oxide (B 2 O 3 ) are deduced from a series of characterizations including XRD, FT‐IR, and TEM characterization. Further studies show that the formation of covalent bonds between B 2 O 3 , SiO 2 , and CDs play a key role in activating the persistent RTP and preventing its quenching. This is a rare example of a persistent RTP system that exhibits hourly persistent RTP under environmental conditions. Finally, the applications of Si‐CDs@B 2 O 3 are demonstrated for anti‐counterfeiting, long‐duration phosphorescence imaging, and fingerprinting. This synthetic strategy is expected to provide strong technical support for the preparation of persistent RTP CDs and pave the way for the synthesis of persistent RTP CDs in the future.