Abstract
Solar water splitting is a promising and ideal route for renewable production of hydrogen by using the
most abundant resources of solar light and water. Focusing on the working principal of solar water splitting, including photon absorption and exciton generation in semiconductor, exciton separation and
transfer to the surface of semiconductor, and respective electron and hole reactions with absorbed
surface species to generate hydrogen and oxygen, this review covers the comprehensive efforts and
findings made in recent years on the improvement for the solar-to-hydrogen efficiency (STH) determined by a combination of light absorption process, charge separation and migration, and catalytic reduction and oxidation reactions. Critical evaluation is attempted on the strategies for improving solar light harvesting efficiency, enhancing charge separation and migration, and improving surface reactions. Towards the end, new and emerging technologies for boosting the STH efficiency are discussed on multiple exciton generation, up-conversion, multi-strategy modifications and the potentials of organometal hybrid perovskite materials.