Synthesis of tailored carbon nitride materials using polycyclic aromatic systems

Graphitic carbon nitrides (g-CN) are one of the synthetic polymers with high physicochemical stability, distinctive optical properties, and an attractive electronic structure. g-CN features allow its direct use as a metal-free polymeric semiconductor in various fields such as photocatalysis, solar cell, heterogeneous catalysis, and other energy-related applications. However, their relative wide band gap limits their visible light harvesting and their activity in solar-related fields. So far, various strategies have been devoted to modulate their light absorption towards the visible region and for enhancing the photo-induced charge carrier separation. Herein our strategy is to design and synthesize highly efficient g-CN-based materials by molecular engineering. The idea of designing a polycyclic aromatic system allows modification of preferred materials and intensifies the conjugate effect. In this work, we have introduced various aromatic rings in the carbon nitride framework to extend π-conjugation for visible light harvesting and also to improve the charge transfer efficiency. The aromatic-modified materials give the π-π stacking configuration which is basically narrow the band gap and enhance the utilization of photo-induced electrons. This work provides a new approach to increase optical absorption, electronic properties, and optimized band arrangements to advance the various applications of functionalized carbon nitrides.