Catechol as a Co‐Polymerization Mediator for Programmable Surface Chemistry Structure Synthesis of Carbon Dots

ABSTRACT Red‐emissive carbon dots (R‐CDs) hold promise for bioimaging and optoelectronics, yet their synthesis under mild, scalable conditions remains challenging. Conventional hydrothermal routes demand high temperature and pressure, while ambient‐pressure alternatives rely on strong acids and yield limited quantum yields without programmable surface control. This work reports a catechol‐assisted ambient‐pressure strategy that achieves hundred‐gram‐scale preparation of R‐CDs by simple heating at ∼90°C. Catechol acts as a co‐polymerization mediator, participating in formation of carbon dots while its dual hydrogen‐bonding network suppresses functional‐group detachment, stabilizes radical intermediates, and lowers the steric barrier for cyclization. This mechanism enables programmable tuning of hydrophilicity/hydrophobicity and emission wavelength by varying the precursor substituents. The hydrophobic carbon dots exhibit a solid‐state quantum yield of 45.26% (encapsulated in polyvinylpyrrolidone), the highest reported, and enable white light‐emitting diodes (WLED) with a color rendering index (CRI) of 94. The hydrophilic carbon dots (quantum yield 37.86%) are directly applied to deep‐tissue in vivo imaging without surface modification. This work provides a versatile molecular engineering platform for sustainable synthesis of functional aromatic carbon nanomaterials.