Laser Fired Contacts in multicrytalline silicon solar cells

Abstract

The roadmap for the development of silicon solar cells requires the introduction of passivating contacts to obtain higher efficiencies as well as to reduce the cost of production to be industrially implemented. In this context, Laser Fired Contact (LFC) on p-type silicon wafers have been shown to be an effective technique to improve efficiencies, due to their ability to reduce recombination losses on the back surface of crystalline silicon solar cells. These studies have mainly focused on high quality monocrystalline silicon wafers and there are not enough developments made with multicrystalline silicon (mc-Si) wafers. Therefore, in this work, we present the optimization of the LFC process on p-type mc-Si and its application to two types of silicon devices: diffusion and heterojunction solar cells. These rear contacts have led to improved efficiencies for both types of solar cells over similar devices with thermalized aluminum rear contacts and without back passivation. These results illustrate the enormous potential of these localized laser-contacts created for mc-Si solar cells, perfectly compatible with a lower cost industrial production.