Solar cell, photovoltaic module, and photovoltaic system

A solar cell, comprising:

• an n-type semiconductor substrate comprising a first surface and a second surface opposite to each other, the second surface comprising a passivation contact region and a passivation region adjacent to each other;
• a first tunneling passivation structure disposed on the first surface, the first tunneling passivation structure comprising a first tunnel layer and a first passivation contact layer stacked in a direction away from the semiconductor substrate, a doping type of the first passivation contact layer is p-type;
• a second tunneling passivation structure disposed on the second surface and located in the passivation contact region of the second surface, the second tunneling passivation structure comprising a second tunnel layer and a second passivation contact layer stacked on the passivation contact region;
• and
• a third tunnel layer and a third passivation layer stacked on the passivation region of the second surface, a thickness of the third passivation layer being less than a thickness of the second passivation contact layer.