Nanostructured hematite: synthesis, characterization, charge carrier dynamics, and photoelectrochemical properties

As one of the most prevalent metal oxides on Earth, iron oxide, especially alpha-Fe2O3 or hematite, has been the subject of intense research for several decades. In particular, the combination of a relatively small bandgap and related visible light absorption, natural abundance, low cost, and stability under deleterious chemical conditions has made it ideal for many potential applications. However, the short charge carrier lifetime or diffusion length has limited its applicability. Nanostructures of hematite offer the possibility of overcoming some of the limitations through control of the structures and thereby its optical and electronic properties. In this review, we provide an overview of recent progress on the synthesis and characterization of nanostructured hematite, with an emphasis on the charge carrier dynamics and photoelectrochemical properties. Both current challenges and future opportunities are also discussed.