Experimentally Determined Spatiotemporal Charge Carrier Dynamics for the Development of Particulate Photocatalysts

Particulate photocatalysts have generated interest for the low‐cost implementation of various photocatalytic processes, including the production of solar fuels as clean energy sources. With light absorption, charge generation, charge transport, and interfacial charge transfer all constrained in individual particles, complex photophysical and photochemical processes occur on a wide range of timescales within spatially defined volumes. The allure of deciphering the charge carrier dynamics to build a fundamental picture of photocatalysis in different materials has motivated the development of state‐of‐the‐art spatiotemporal measurement techniques. Monitoring charge carrier dynamics on relevant time and length scales is a challenging experimental task. Many experimental barriers have been overcome in recent years, providing some guidance for future directions for material development. This review delves into the underlying origins of spatial heterogeneity in charge carrier dynamics, introduces charge carrier transport phenomena, and details the recent examples of spatiotemporal investigation of charge carrier dynamics in particulate photocatalysts. These new experimental capabilities pave the way for a more comprehensive description of photocatalytic processes, guiding the optimization of photocatalytic materials.