Solar cell and preparation method therefor

A method for preparing a solar cell, comprising the following steps of:

• forming a first silicon oxide layer, an intrinsic amorphous silicon layer, a phosphosilicate glass layer, and a second silicon oxide layer sequentially on a back surface of an n-type silicon substrate;
• removing the phosphosilicate glass layer and the second silicon oxide layer on a partial region of the back surface of the n-type silicon substrate;
• performing boron diffusion on the back surface of the n-type silicon substrate, so that the intrinsic amorphous silicon layer in a region where the phosphosilicate glass layer and the second silicon oxide layer are removed is converted into a boron-doped polysilicon layer, and the intrinsic amorphous silicon layer in a region where the phosphosilicate glass layer and the second silicon oxide layer are not removed is converted into a phosphorus-doped polysilicon layer;
• forming an isolation groove at a boundary between the boron-doped polysilicon layer and the phosphorus-doped polysilicon layer;
• and
• preparing a first electrode connected to the boron-doped polysilicon layer and a second electrode connected to the phosphorus-doped polysilicon layer.