Insight into structure evolution of carbon nitrides and its energy conversion as luminescence

A series of carbon nitride (CN) materials represented by graphitic carbon nitride (g-C3N4) have been widely used in bioimaging, biosensing, and other fields in recent years due to their nontoxicity, low cost, and high luminescent quantum efficiency. What is more attractive is that the luminescent properties such as wavelength and intensity can be regulated by controlling the structure at the molecular level. Hence, it is time to summarize the related research on CN structural evolution and make a prospect on future developments. In this review, we first summarize the research history and multiple structural evolution of CN. Then, the progress of improving the luminescence performance of CN through structural evolution was discussed. Significantly, the relationship between CN structure evolution and energy conversion in the forms of photoluminescence, chemiluminescence, and electrochemiluminescence was reviewed. Finally, key challenges and opportunities such as nanoscale dispersion strategy, luminous efficiency improving methods, standardization evaluation, and macroscopic preparation of CN are highlighted. Schematic diagram for the structural evolution of carbon nitride and its luminescent energy conversion image