Microwave‐Assisted Confining Growth and Liquid Exfoliation of sp3‐Hybrid Carbon Nitride Nano/Micro‐Crystals

As one promising carbon‐based material, sp 3 ‐hybrid carbon nitride has been predicted with various novel physicochemical properties. However, the synthesis of sp 3 ‐hybrid carbon nitride is still limited by the nanaoscale, low crystallinity, complex source, and expensive instruments. Herein, we have presented a facile approach to the sp 3 ‐hybrid carbon nitride nano/micro‐crystals with microwave‐assisted confining growth and liquid exfoliation. Actually, the carbon nitride nano/micro‐crystals can spontaneously emerge and grow in the microwave‐assisted polymerization of citric acid and urea, and the liquid exfoliation can break the bulk disorder polymer to retrieve the highly crystalline carbon nitride nano/micro‐crystals. The obtained carbon nitride nano/micro‐crystals present superior blue light absorption strength and surprising photoluminescence quantum yields of 57.96% in ethanol and 18.05% in solid state. The experimental characterizations and density functional theory calculations reveal that the interface‐trapped localized exciton may contribute to the excellent intrinsic light emission capability of carbon nitride nano/micro‐crystals and the interparticle staggered stacking will prevent the aggregation‐caused‐quenching partially. Finally, the carbon nitride nano/micro‐crystals are demonstrated to be potentially useful as the phosphor medium in light‐emitting‐diode for interrupting blue light‐induced eye damage. This work paves new light on the synthesis strategy of sp 3 ‐hybrid carbon nitride materials and thus may push forward the development of multiple carbon nitride research.