We demonstrate the application of a liquid-processed doped silicon precursor as a doping source for the fabrication of interdigitated back contact solar cells. We integrate phosphorus- as well as boron-doped liquid silicon in our n-type interdigitated back contact cell process based on laser-structuring. The cell with the phosphorus back surface field from liquid silicon has an efficiency of 20.9% and the cell with the boron emitter from liquid silicon has an efficiency of 21.9%. We measure saturation current densities of 34 fA cm(-2) on phosphorus-doped layers with a sheet resistance of 108 Omega/sq and 18 fA cm(-2) on boron-doped layers with a sheet resistance of 140 Omega/sq using passivated test samples.