Plasmonic nanoparticles are widely used for light harvesting in photovoltaics and photocatalysis, including in artificial photosynthesis. Just like an antenna, gold or silver nanoparticles receive light and transfer the energy to, for instance, a quantum dot in the vicinity.

Tetsu Tatsuma and colleagues, University of Tokyo, Japan, developed a new, star-shaped gold nanoantenna coated with an ultrathin zinc oxide (ZnO) layer. The nanoantenna assists in the light absorption of a lead sulfide (PbS) quantum dot. This is particularly important in the near infrared region, in which the light absorption ability of the quantum dot is usually low. The quantum dots are deposited onto a ZnO layer, which maintains the optimum distance between the nanoantenna and the quantum dots.

Since the nanoantenna extends branches in various directions, it can also receive light of various incident and polarization angles. Together, these components give a structure with an enhanced photoelectrochemical reaction rate.

• Branched Au Nanoparticles as Light-Harvesting Antennae for Photosensitized Reactions,
  Tokuhisa Kawawaki, Akihiro Asakura, Tetsu Tatsuma,
  ChemNanoMat 2015.
  DOI: 10.1002/cnma.201500140