Molecular devices featuring sequential photoinduced charge separations for the storage of multiple redox equivalents

The present review focuses on one facet of artificial photosynthesis: the charge photo-accumulation function, which has been much less investigated than photoinduced energy or electron transfer reactions. However, charge accumulation is certainly of fundamental importance to perform reactions involving multiple redox equivalents, such as most fuel making reactions. Indeed, the charge photo-accumulation function is specifically relevant to the efficiency of artificial photosynthetic devices and represents an essential property of the photosystem II in oxygenic photosynthetic organisms. We introduce the general concept of charge photo-accumulation, which consists in the collection of multi-redox equivalents at specific sites upon consecutive multiple photon absorptions. We survey the existing artificial molecular systems capable of multiple charge storage upon successive light excitations and new directions for future developments in this area are presented. (C) 2010 Elsevier B.V. All rights reserved.