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Crystalline silicon solar cell with porous silicon back reflection layer

A crystalline silicon solar cell with a porous silicon back reflection layer is characterized by comprising a front electrode (1), a surface passivation layer (2), an N-typed silicon layer and texture structure (3), a PN structure (4) which is formed at the juncture of an N-typed layer and a P-typed layer and has photovoltaic effect, a P-typed silicon substrate (5), a porous silicon back reflection layer (6), a back passivation layer and a back electrode (7) in a downward arrangement order from an illuminated surface; the surface of a silicon material surface on one side near an unilluminated surface is provided with a porous silicon Bragg reflector with alternately variable porosity, thus improving the photoelectric conversion efficiency of the solar cell.