Metal-organic frameworks as semiconductors

The aim of the present feature article is to present the current evidence in support of considering some MOFs as semiconductors. While MOFs and zeolites share common structural properties derived from the microporous crystal structure, zeolites are insulating materials and most of the attempts to exploit them in optoelectronics have met with failure. In contrast, some MOFs may have interesting photochemical properties that derive from the fundamental event of charge separation in electrons and holes upon light absorption. Photoinduced charge separation is the hallmark of a semiconductor that can behave simultaneously as an oxidizing or reducing agent. Considering the novelty of this field, most of the available data about MOFs as semiconductor have been obtained from MOF-5, a case that is complicated due to its low structural stability. Therefore, we point out that further studies showing the semiconducting properties of other MOFs are still welcome. The purpose of this feature article is to trigger intense research in this area including the synthesis of semiconducting MOFs by design and development of applications.