Apparatus and methods for forming optoelectronic devices such as an array of light emitting diodes or photovoltaic cells are disclosed. In one embodiment, a roll-to-roll process in which a uniquely configured roller having a raised spiral coating surface is aligned with a plurality of first electrodes disposed on an angle on a substrate for coating a plurality of spaced-apart angled coated strips of optoelectronic materials along the cross-web direction of the substrate.