Synergistic effects of vegetal melanin and porous silicon powder to improve the efficiency of solar panel

Abstract

Porous Silicon powder (PSP) luminescent combined with the UV absorption and Chelant agent properties of the melanin creates a colloidal solution whose characteristics could be applied to the solar cells for increase the conversion efficiency. This study is focused in the change of the PSP concentration added to the melanin solution and how this modifies the conversion efficiency in solar cells under the down conversion process. The concentration of the melanin was constant at 0.1 mg/ml of dimethyl sulfoxide (DMSO). Three different amounts of PSP were added 3, 9 and 20 mg in 1 ml of melanin to obtain three colloidal solutions of melanin/PSP. The melanin/PSP solution has different optical properties; one of them is two photoluminescence (PL) emission bands. The first PL band has a range from 530 to 605 nm and the second one between 670 and 715 nm. The PL spectra have different intensities due to the each concentration of the PSP and under UV radiation three distinct colors could be appreciated. However, the emission is correlated to the down conversion effect of the PSi and the high intensity luminescence corresponds to the Melanin UV absorption and the passivation of the PSi particles due to the chelant property which is appreciated with the transmission electron microscope micrographs. Each Melanin/PSP colloidal solutions were deposited on the protection glass from the solar panel with an amount of 10 µl. The efficiency measurements of the solar cells were done before and after of the solar panels were assembled and compared. The increments of the energy efficiency of the solar panel were around range of 3 % which depends of the distribution of the melanin/PSP colloidal solution over the glass. This study shows a way to apply the properties of the melanin for the development of optoelectronics devices.