CHAPTER 6: Atomic and Molecular Functionalization of Graphitic Carbon Nitride for Solar Cell Applications

Graphitic carbon nitride (g-C₃N₄) nanomaterials have attracted great attention in various energy and environmental applications owning to their unique physical and chemical properties. The utilization of gCNs in solar-driven energy production is amongst the hottest research topics and is critical to fulfilling human energy needs. gCN materials have outstanding photocatalytic and optical properties and great stability (i.e., thermal, chemical, and physical), which enables their usage in solar cell applications. However, the practical application of gCNs in solar cells is precluded by the difficulty of preparing solar-active thin films, their inferior visible light absorption > 460 nm, and quick electron–hole recombination, which all could be defeated by various approaches such as doping or functionalization with metals and metal oxides, or formation of a heterojunction structure with other materials. Thereby, the number of articles related to the rational design of gCNs for solar cell applications has increased substantially over the past decade, so it is important to provide a periodic update on this research area. This article emphasizes atomic and molecular functionalization of gCNs for solar cell applications ranging from the fabrication methods of gCN films (i.e., coating, assembling, solid/liquid mediated growth, and gas-phase noncontact growth) to solar cell devices (i.e., in dye-sensitized, organic, perovskite, and quantum dot solar cells). Lastly, the chapter is completed by highlighting the current barriers and future outlook for implementing gCNs in the next-generation of solar cells.