Progress of charge carrier dynamics and regulation strategies in 2D CN-based heterojunctions

Two-dimensional carbon nitrides (CN) have gained significant attention in various fields including hydrogen energy development, environmental remediation, optoelectronic devices, and energy storage owing to their extensive surface area, abundant raw materials, high chemical stability, and distinctive physical and chemical characteristics. One effective approach to address the challenges of limited visible light utilization and elevated carrier recombination rates is to establish heterojunctions for CN-based single materials (e.g. C₂N₃, g-C₃N₄, C₃N₄, C₄N₃, C₂N, and C₃N). The carrier generation, migration, and recombination of heterojunctions with different band alignments have been analyzed starting from the application of CN with metal oxides, transition metal sulfides (selenides), conductive carbon, and CN heterojunctions. Additionally, we have explored diverse strategies to enhance heterojunction performance from the perspective of carrier dynamics. In conclusion, we present some overarching observations and insights into the challenges and opportunities associated with the development of advanced CN-based heterojunctions.