Quinacridone dyes: versatile molecules and materials for photo- and photoelectrochemical processes

The renaissance of photochemistry and the explosion of photo- and photoelectro-catalysis open new opportunities in organic photocatalyst design and applications towards solar fuels and sustainable organic reactivity. In this perspective, we discuss the relevant case of quinacridone (QA) dyes: these have long been known to the scientific community, but their application in photocatalysis is recent and still explored in a limited way. This is somehow surprising given that QA is a cheap and readily available organic pigment, and in front of the appealing properties of QA derivatives, including intense absorption in the visible region, balanced redox properties making them suitable for both oxidative and reductive photochemistry, and versatility to several operative conditions. We will discuss recent examples of photo- and photoelectrochemical processes taking advantage of QA dyes, from solution photocatalysis to photoactive materials and devices (nanoparticles, covalent organic frameworks, photoelectrodes); the target applications include water splitting, carbon dioxide reduction, and organic transformations. We aim to show the potential of organic photocatalyst design and implementation, and to inspire the readers with new opportunities in this field.We discuss the versatility of quinacridone pigment in photocatalysis, embracing water splitting, carbon dioxide reduction and organic synthesis. Applications include homogeneous catalysis, nanoparticles, covalent organic frameworks, photoelectrodes.