Most PV cells manufactured today are called P-type. The body of the cell is doped with Boron while its front surface is doped with Phosphorus in order to create the P-N junction which is the source of electrical production. For an N-type cell it is the opposite, the cell body is doped with Phosphorus and its surface with Boron. N-type technology is more efficient because the material is more "pure" (less metallic impurities) and insensitive to LID.