Continuous Photochemical Applications of UV-A, UV-B and UV-C LEDs

This graphical review presents an overview of case studies published within the last six years detailing the use of UV LEDs for continuous flow-based photochemical transformations. The exploitation of LEDs emitting in the UV region thereby provides high-energy near-monochromatic light which offers advantages over traditional, yet energy-inefficient metal-vapor lamps. Moreover, our compilation shows that the dominance of UV-A LEDs is being reduced as commercially available LEDs emitting UV-B and UV-C light are being applied to continuous photochemical reactions. These developments clearly highlight the value of UV-LEDs in supporting photochemistry at lower wavelengths which complement visible-light based photocatalytic methods. Both approaches enhance the effective use of light in triggering reactions without recourse to stoichiometric reagents with the potential to improve the overall safety and sustainability of these processes.