The disclosure relates to the technical field of solar cells, and provides a solar cell and a doped region structure thereof, a cell assembly, and a photovoltaic system. The doped region structure includes a first doped layer, a passivation layer, and a second doped layer that are disposed on a silicon substrate in sequence. The passivation layer is a porous structure having the first doped layer and/or the second doped layer inlaid in a hole region. The first doped layer and the second doped layer have a same doping polarity. By means of the doped region structure of the solar cell provided in the disclosure, the difficulty in production and the limitation on conversion efficiency as a result of precise requirements for the accuracy of a thickness of a conventional tunneling layer are resolved.

A solar cell, a preparation method thereof, and a photovoltaic module. The solar cell includes a semiconductor substrate, a first substrate doped layer, a second substrate doped layer, a first passivation layer, and a first doped semiconductor layer. The semiconductor substrate includes a first surface, and the first surface includes a first region and a second region adjacent to the first region along a first direction. The first substrate doped layer is located in the first region. The second substrate doped layer is located in the second region, and the first substrate doped layer is connected to the second substrate doped layer. The first passivation layer is located on a side of the second substrate doped layer away from the semiconductor substrate. The first doped semiconductor layer is located on a side of the first passivation layer away from the semiconductor substrate.