Solar cell and manufacturing method thereof, and photovoltaic module

A photovoltaic module, comprising:

• a cover plate;
• a packaging material layer;
• and
• at least one solar cell string, wherein the at least one solar cell string includes a plurality of solar cells and at least one of the plurality of solar cells includes:
• a semiconductor substrate, the semiconductor substrate including a first surface and a second surface arranged opposite to each other;
• an emitter and a first passivation layer formed over the first surface of the semiconductor substrate;
• a tunneling layer formed over the second surface of the semiconductor substrate;
• a first doped conductive layer and a retardation layer formed on a surface of the tunneling layer, wherein the first doped conductive layer is located between the tunneling layer and the retardation layer, and the first doped conductive layer and the retardation layer correspond to a metallization region;
• a second doped conductive layer formed over the surface of the tunneling layer, the second doped conductive layer covering the tunneling layer in a non-metallization region and the retardation layer, wherein the retardation layer is configured to retard migration of a doped element in the second doped conductive layer to the first doped conductive layer;
• a second passivation layer formed over a surface of the second doped conductive layer;
• and
• a second electrode penetrating through the second passivation layer to form contact with the second doped conductive layer and a first electrode penetrating through the first passivation layer to form contact with the emitter,
• wherein a doping concentration of the second doped conductive layer is greater than a doping concentration of the first doped conductive layer.