CdSe Nanowire/Fullerene Nanocomposite Photoelectrode: Charge Separation and Photoelectrochemical Behavior

The fabrication of semiconductor nanocomposites with a staggered band-edge alignment has been widely adapted to facilitate charge separation, thus harnessing more photons in light-harvesting systems. To date, a variety of semiconductor nanocomposites have been developed ranging from purely inorganic nanocomposites to organic/inorganic hybrid analogues. Among the organic/inorganic hybrid nanocomposites, semiconductor/fullerene (C60) based nanoheterostructures have been widely investigated due to the excellent electron-accepting ability of C60. While a wide variety of QD/C60 hybrid nanocomposites have been reported, no attempt has been made toward combining semiconductor nanowires (NWs) with C60 to date. In comparison to QDs, semiconductor NWs can be potentially advantageous in several respects when they serve as a light harvester because of their asymmetric geometry. Superior intrinsic properties induced by the one-dimensional nanostructure, such as higher charge carrier mobility and larger absorption cross section, are representative benefits they can provide. In this study, we have for the first time examined the photoelectrochemical performance of photoelectrodes comprised of CdSe NWs and CdSe NWs/C60 nanocomposite and have investigated the beneficial effect of C60 as a coupling material. We found that the CdSe NWs/C60 photoelectrode showed considerably enhanced performance than its counterpart, CdSe NWs. To elucidate the improvement, electron transfer kinetics and optical properties of the nanocomposite were investigated in this work