Fluorescent Carbon Nitride Macrostructures Derived from Triazine‐Based Cocrystals

Abstract Carbon nitride (CN) based materials have emerged as efficient photo‐ and electrocatalysts for various reactions. However, despite their intriguing optical properties (i.e., fluorescence), their utilization as solid‐state sensing platforms remains in its infancy, owing to the formation of defect states during the materials synthesis, leading to low emission for the CN powder. Here, a bottom‐up synthesis of CN macrostructures with good photoluminescence properties in both liquid and solid state is introduced, from designed triazine‐based cocrystals with ordered morphology and tailored chemical composition. Upon calcination at 500 °C, the starting morphology and chemical composition are retained, resulting in the alteration of the HOMO‐LUMO distribution of the CN materials, as further supported by density functional theory (DFT) calculations. The good photoluminescence properties of the new CN materials enable their exploitation as environmentally friendly, robust, and cheap sensing material for latent fingerprints labeling and metal‐ion detection in water.