The invention discloses a
solar cell and a preparation method thereof, and a photovoltaic module. The
solar cell comprises a substrate and a
passivation contact structure. Wherein the substrate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction of the substrate; the
passivation contact structure is arranged on the first surface of the substrate; the
passivation contact structure comprises a tunneling
oxide layer and a
polycrystalline silicon layer arranged on one side, deviating from the substrate, of the tunneling
oxide layer; the
polycrystalline silicon layer comprises at least one first doped
polycrystalline silicon layer; the
carbon doping amount of the first doped polycrystalline
silicon layer is gradually increased along the direction gradually away from the substrate. According to the passivation contact structure in the
solar cell provided by the invention, by inserting the carbon-containing first doped polycrystalline
silicon layer of which the
carbon doping amount increases progressively into the polycrystalline
silicon layer, the polycrystalline silicon
layers in different regions can have different H distribution states, so that the concentration of H in the tunneling
oxide layer is effectively avoided, and finally the purposes of reducing the film explosion rate and improving the performance of the solar
cell are achieved. And the phenomenon of membrane explosion of the battery is reduced.