Internal electric field engineering for steering photogenerated charge separation and enhancing photoactivity

Photocatalysis as a desirable technology shows great potential in environmental remediation and renewable energy generation, but the recombination of photogenerated carriers is a key limiting factor for efficiency in artificial photosynthesis. Internal electric field (IEF, also known as built-in electric field) engineering acts an emerging and clearly viable route to increase photocatalytic efficiency by facilitating charge separation and transfer. This review summarizes the basic principles of IEF including the source, the strategies for the enhancement and the measurement of IEF. Highlight is the recent progress in steering photogenerated charge separation of photocatalysts by IEF engineering and related mechanisms. Finally, the challenges in IEF engineering and exciting opportunities to further enhancing charge separation and photocatalytic performance are discussed.