In electronic excited states, charge carriers such as electrons and holes (the absence of an electron) play a crucial role. These carriers can move through the catalyst material and interact with reactants. The efficiency of a photocatalytic process depends on the lifespan and mobility of these charge carriers. If they recombine too quickly, the energy is lost as heat rather than being used for chemical reactions. To improve efficiency, materials with long-lived charge carriers and high mobility are often sought after.
