Abstract: In general, the present invention relates to electro-conductive pastes with halogen containing compounds as additives and solar cells with high Ohmic sheet resistance, preferably photovoltaic solar cells. More specifically, the present invention relates to solar cell precursors, processes for preparation of solar cells, solar cells and solar modules. The present invention relates to a solar cell precursor at least comprising as precursor parts: i) a wafer with sheet resistance of at least 80 Ohm/sq.; ii) an electro-conductive paste at least comprising: a) metallic particles; b) a glass frit; c) an organic vehicle; and d) a halogen containing compound applied to the wafer.