Solar cell and preparation method therefor

A method of preparing a solar cell, comprising:

• conducting a boron diffusion on a substrate to form a boron diffusion layer on a surface of the substrate and a borosilicate glass on a surface of the boron diffusion layer;
• using a first surface of the substrate as a back of the substrate, and sequentially conducting laser slotting and boron diffusion layer etching on partial area of the borosilicate glass on the back of the substrate to form back surface field regions, areas without being slotted and etched being emitter regions, and the emitter regions and the back surface field regions being configured to alternate on the back of the substrate;
• growing a tunnel oxide layer on the back of the substrate, followed by depositing an intrinsic amorphous silicon layer;
• conducting a phosphorus diffusion on the substrate, so as to cause the intrinsic amorphous silicon layer to form a polysilicon layer made of phosphorus doped polysilicon and create a phosphosilicate glass on the surface of the polysilicon layer;
• printing a corrosion resistant slurry being soluble in alkali but insoluble in acid on a surface of the phosphosilicate glass corresponding to the back surface field regions and drying the corrosion resistant slurry to form an alkali-soluble but acid-insoluble layer;
• removing the phosphosilicate glass corresponding to the emitter regions with acid;
• removing the alkali-soluble but acid-insoluble layer and the polysilicon layer and the tunnel oxide layer corresponding to the emitter regions with alkali;
• removing the remaining phosphorosilicate glass and borosilicate glass on the back of the substrate with acid;
• using the remaining boron diffusion layer in the emitter regions as emitters, and using the remaining tunnel oxide layer and polysilicon layer in the back surface field regions as back surface fields;
• and
• electrically connecting a positive electrode to the emitter and electrically connecting a negative electrode to the back surface field.