Doped region structure and solar cell comprising the same, cell assembly, and photovoltaic system

A photovoltaic system, comprising:

• a solar cell, comprising:
• a silicon substrate;
• a doped region structure disposed on a back side of the silicon substrate, the doped region structure comprising a first doped layer, a passivation layer, and a second doped layer that are disposed on the silicon substrate in sequence;
• a first dielectric layer, disposed on the doped region structure;
• a third doped layer and a second dielectric layer, disposed on a front side of the silicon substrate in sequence;
• and
• a first conductive layer and a second conductive layer, respectively electrically connected to the doped region structure and the third doped layer;
• wherein:
• the doped region structure and the third doped layer have opposite polarities;
• the passivation layer includes a plurality of porous structures and a plurality of hole regions interposing with each other, a hole region of the plurality of hole regions includes a through hole extending through the passivation layer, a porous structure of the plurality of porous structures includes an opening at a surface of the passivation layer, the first doped layer and/or the second doped layer are disposed in the hole region, and a conductive channel is formed in the hole region of the passivation layer and connects the first doped layer and the second doped layer;
• and
• the second doped layer is connected to the silicon substrate through the doped hole region and the first doped layer.

A solar cell, comprising:

• a silicon substrate;
• a doped region structure disposed on a back side of the silicon substrate, the doped region structure comprising a first doped layer, a passivation layer, and a second doped layer that are disposed on the silicon substrate in sequence;
• a first dielectric layer, disposed on the doped region structure;
• a third doped layer and a second dielectric layer, disposed on a front side of the silicon substrate in sequence;
• and
• a first conductive layer and a second conductive layer, respectively electrically connected to the doped region structure and the third doped layer;
• wherein:
• the doped region structure and the third doped layer have opposite polarities;
• the passivation layer is a porous structure comprising a hole region, and the first doped layer and/or the second doped layer are disposed in the hole region, and a conductive channel is formed in the hole region of the passivation layer and connects the first doped layer and the second doped layer;
• and
• the second doped layer is connected to the silicon substrate through the doped hole region and the first doped layer, wherein the second doped layer comprises a silicon carbide doped layer, the silicon carbide doped layer comprising multiple silicon carbide doped films, and refractive indexes of the multiple silicon carbide doped films decrease in a direction from the silicon substrate to an exterior of the solar cell.