Physical vapour deposition reactive magnetron sputtering for the production and application of dichroics in photovoltaic system with solar spectral splitting

Abstract

This paper aims at designing, producing and characterizing a series of dichroic filters that are made up of a stack of layers with variable nanometer thickness. Such filters are created by PVD reactive magnetron sputtering, obtaining SiO2 and TiO2 through an active oxidation during the deposition. The single layers have then been analyzed using different techniques including RBS (Rutherford Backscattering Spectrometry) to determine the stoichiometry, AFM (Atomic Force Microscope) to assess the deposition rate, and UV–vis–NIR spectrophotometric analysis to evaluate the optical response. The application of the dichroic in concentration photovoltaic systems, separates the solar radiation in two optical spectral bands [7], that allows to couple them with a different solar cells which have dedicated external quantum efficiency. The optical separation using dichroic filters allows to combine different photovoltaic cells with an appropriate energy gap, thus optimizing the photovoltaic conversion.