Screen-Printed Silicon Solar Cells with LCP Selective Emitters

Abstract

Fully functional large area screen-printed multi-crystalline silicon solar cells with Laser Chemical Processing (LCP) selective emitters were obtained for the first time. Solar cell efficiencies between 14.4 and 15.2 % were achieved. The absolute efficiency gain of 0.3 %abs was obtained by the application of the LCP process on the lowly doped (120 Ω/sq) emitter in comparison to reference solar cell without the LCP process. The application of the LCP selective emitter increased the fill factor of the solar cells in comparison to the reference solar cells. The efficiency gain of these first solar cells proves the concept of applying the LCP to the standard solar cell structure. However, the overall efficiency was strongly limited by the large width of the metal fingers and the resulting shading and contact recombination losses. Also the non-optimized metal finger distance is limiting the FF of the solar cells with high emitter sheet resistance. Thus the efficiency of the solar cells with lowly doped emitter was lower than in the case of highly doped emitter. A detailed characterization of the processed solar ells is presented.