Luminescent polymeric film containing an Eu(III) complex acting as UV protector and down-converter for Si-based solar cells and modules

Abstract

A new polymeric film based on an Eu(III) complex embedded in polymethylmethacrylate (PMMA) have been chemically, thermally and optically analyzed in order to be used as downconverter layer on Si-based solar cells. Photoluminescence excitation (PLE) and emission (PL) spectra show a strong UV excitation band between 250 and 360 nm leading to an intense emission band around 615 nm where the external quantum efficiency (EQE) of a conventional solar cell reaches maximum values. Thickness and viscosity of the active polymeric coating have been studied in order to increase the photoconversion efficiency of the layer. Surface topography has been analyzed with SEM and AFM techniques. Thermogravimetric measurements show that the luminescent film is thermally stable up to 225º C, accomplishing the temperature requirements for Si solar modules fabrication. Increase of the EQE is expected after a proper encapsulation of the solar cell and the glass. Moreover, UV absorption of the down-converter protects and enhances the stability of the solar module structure.