Water‐Soluble Graphite‐Phase Carbon Nitride Colloid and Its Multichannel Biological Imaging Effect

Abstract Due to the large band gap and quantum size effect, most of reported fluorescent graphite phase carbon nitride (GCN) nanosheets/quantum dot emits blue fluorescence under ultraviolet, which limits its further application in bio‐imaging. However, diversified strategies of PL wavelength tailored are rare except for heteroatom or molecule doping. In this paper, yellowish carbon nitride colloid with 508 nm PL emission was produced through structural self‐modulation method using melamine as sole precursor. The obtained colloid demonstrate nontoxicity, stability (up to 10 month), good dispersibility in water and green fluorescent under 365 nm light excitation. Associated with its broad emission peak excited by different wavelengths of light, it shows good performance in biological imaging and importantly, realizes blue, green and red three‐channels imaging. To the best of our knowledge, this is the first time to report multi‐channel biological imaging based on GCN polymer with long PL wavelength by structural self‐modulation strategy.