Localisation of front side passivating contacts for direct metallisation of high-efficiency c-Si solar cells

In this work, we present the development of passivating contacts based on thin interfacial oxide/doped polysilicon for two side contacted c-Si solar cells. In the first part, we discuss our layer optimization towards direct metallisation, using firing through of Ag-paste screen printed on a silicon nitride (SiNx:H). By optimising the poly-silicon thickness, we obtain solar cells with open circuit voltage (V-OC) up to 700 mV and fill factor (FF) up to 78%. However, such results were obtained by using layers with a thickness of 95 nm, strongly limiting the short circuit current density. To overcome this limitation, we present in the second part an approach for localization of the front side passivating contact by means of deposition through a shadow mask. Finally, in the third part, we demonstrate high-efficiency c-Si solar cells with promising efficiency above 21.7% with a V-OC of similar to 711 mV, a high FF of 79.7% and a potential for efficiency >22%.