Frequency conversion to augment power conversion efficiency in photovoltaic devices

To attain high power conversion efficiencies in photovoltaic devices majorly requires proper matching between the optoelectronic properties of the photoactive layer and the solar emission spectrum for maximum absorption of the solar photon flux. Up- and down-conversion using rare earth-doped layers represent the predominantly used approaches to tune the solar emission spectrum and synchronise it with the band gap energy of the photoactive layer in a solar cell. Here we demonstrate that the same role can be realised using geometrical effects and dielectric shells encapsulating nanoparticles to tune the position of the plasmonic resonances as an alternative pathway to frequency shift. The introduction of a dielectric coating of SiO2 to passivate these nanoparticles induces large shifts in the absorption resonance, leading to the enhancement of power conversion efficiencies in Silicon based solar cells.