Self‐Assembled Plasmonic Oligomers for Organic Photovoltaics

Introducing plasmonic resonant scatterers in photovoltaic devices is a promising way to increase energy conversion efficiencies by trapping incoming light in ultra‐thin solar cells. Colloidal plasmonic oligomers are obtained following a cost‐effective self‐assembly strategy and incorporated in organic‐based cells produced using spin‐coating techniques in ambient air conditions. An interesting increase is observed of both external quantum efficiency (EQE) and short‐circuit current for solar cells loaded with plasmonic oligomers compared with reference organic cells with and without isolated gold nanoparticles. Theoretical calculations demonstrate that the wavelength‐dependent EQE enhancement is a resonant process due to the increased scattering efficiency in plasmonic antennas allowed by a chemically controlled 1 nm nanogap. This method opens the way towards roll‐to‐roll fabrication of efficient plasmonic ultra‐thin photovoltaic devices.