Germanate glass layer containing Eu3+ ions and gold nanoparticles for enhanced silicon solar cell performance

Abstract

Efficiency enhancement of solar cells is a goal of the photovoltaic industry, and different approaches can be used to achieve this objective. For example, the modification of the incident solar spectra using down shift spectral converters covering the solar cell represents an alternative that has been reported in the literature. In this case, there is an interplay between the gain in the efficiency due to the modification of the incident solar spectra and the losses attributed to absorption and reflection of these layers. In order to mitigate this problem, an immersion oil between the solar cell and the luminescent layer can be used to match the differences between the linear refractive indices. Besides, the luminescence of rare earths in the visible spectra can be enhanced by metallic nanoparticles. Employing these strategies, we present results of germanate glasses with rare earth ions and gold nanoparticles to enhance silicon solar cell performance when used as cover layer. Efficiency increase of about 18.42% is demonstrated for silicon solar cells covered with GeO2-PbO glasses doped with Eu3+ ions and containing spherical gold nanoparticles with average size around 8 nm.