Screen printed c-Si thin film solar cells on insulating substrates

A simple industrially feasible process scheme, the screen printed Buried Base Contact (BBC) concept, was applied to Cz-Si wafers as well as to c-Si thin films (CSiTF) on insulating substrates. Cells with interdigitated front grid design on untextured Cz-Si wafers show fill factors up to 73 % and a maximum efficiency of 11.5 %. The application of the process to CSiTF on insulating substrates yields in an V-oc of 509 mV. Despite series resistance values below 1 Omegacm(2) the cells are severely limited by a low fill factor as well as an inactive cell area of 27 % including grid shading and unpassivated base area. In particular, rough surfaces of the CSiTF's prevent good printing alignment, resulting in shunt resistances below 50 Omegacm(2). These first results lead to a 3 % efficiency of CSiTF cells. Thus, the challenge for future oneside contacting schemes will be the modification of the BBC concept regarding reduced alignment requirements.