Solar cell

A solar cell having a cell unit comprising a semiconductor substrate, at least two doping regions, at least one insulating layer, at least two first electrode, at least one first doping layer, and at least one second electrode is provided. The two adjacent doping regions extend from the surface of the semiconductor substrate into the semiconductor substrate. The insulating layer having at least two openings covers two adjacent doping regions and a portion of the surface of the semiconductor substrate, wherein the sum of the area of the openings is A; the total area of the semiconductor substrate is B, and 2% ≤ ((A/B)*100%) ≤ 9%. The first electrodes disposed on the insulating layer contact to two adjacent doping regions through the openings respectively. The first doping layer is disposed on the insulating region and between two adjacent first electrodes. The second electrode is disposed on the first doped layer.