Photoinduced charge separation at heterojunctions between two-dimensional layered materials and small organic molecules

p–n heterojunctions are fundamental components for electronics and optoelectronics, including diodes, transistors, sensors, and solar cells. Over the past few decades, organic–inorganic p–n heterojunctions have garnered significant interest due to the diverse properties they exhibit, which are a result of the limitless combinations of organic molecules and inorganic materials. This review article concentrates on photoinduced charge separation and photocurrent generation at heterojunctions between two-dimensional layered materials and structurally well-defined organic small molecules. We highlight representative examples, including our work, and critically discuss their potential and perspectives.