Graphitic Carbon Nitride Nanomaterials for Multicolor Light-Emitting Diodes and Bioimaging

The application of fluorescent graphitic carbon nitride (g-C₃N₄) nanomaterials was limited by short photoluminescence (PL) wavelength. It is great desirable to develop g-C₃N₄ nanomaterials with long PL wavelength and high quantum yield to expand their application. Herein phenyl-modified and sulfur doped g-C₃N₄ (PhCNS) powders with tunable PL peak from 520 to 630 nm were prepared by copolymerization of 2,4-diamino-6-phenyl-1,3,5-triazine and trithiocyanuric acid. The copolymerization process of PhCNS powders was proposed after chemical structure characterization and PL mechanism of PhCNS powders were investigated by transient fluorescence. In virtue of tunable PL color, broad PL peak, and high quantum yield, PhCNS powders were utilized to fabricate green, yellow, and white light-emitting diodes with high color quality and PhCNS nanosheets were applied for multicolor bioimaging. This work provides a pathway for exploring g-C₃N₄ nanomaterials with long PL wavelength and facilitates their application in biocompatible optoelectronic devices, fluorescent bioimaging.