Study on the Performance of Aluminum Thick Film Contacts for Silicon Solar Cells

Abstract

Aluminum rear contacts of silicon solar cells are made commonly by screen-printing aluminum paste and sintering process. Aluminum thick film contacts have a direct effect on photoelectric properties of solar cells, like open circuit voltage (Voc), short circuit current (Isc), conversion efficiency (η), etc. The principle of Al-back surface field (BSF) has been studied in this paper. With thermal gravimetric analysis and differential scanning calorimetry (TGA-DSC) method, the chemical reactions between aluminum thick film and silicon substrate during heat treatment have been investigated. The microstructure of aluminum thick film contacts were analysed by SEM. The electrical properties of Al-BSF are improved by adding a proper amount of nano silicon to the aluminum paste.