A solar cell making method includes steps of making a round P-N junction preform by (a) stacking a P-type silicon layer and a N-type silicon layer on top of each other, and (b) forming a P-N junction near an interface between the P-type silicon layer and the N-type silicon layer, wherein the round P-N junction preform defines a first surface and a second surface; forming a first electrode preform on the first surface and forming a second electrode preform on the second surface, thereby forming a round solar cell preform; and forming a photoreceptive surface with the P-N junction exposed on the photoreceptive surface by cutting the round solar cell preform into a plurality of arc shaped solar cells, the photoreceptive surface being on a curved surface of the arc shaped solar cell and being configured to receive incident light beams.