Heterojunction cell and method for preparing same

A heterojunction cell, wherein the heterojunction cell comprises

• a semiconductor substrate layer;
• and
• an intrinsic semiconductor composite layer, wherein the intrinsic semiconductor composite layer is located on a surface of at least one side of the semiconductor substrate layer, and the intrinsic semiconductor composite layer comprises a bottom intrinsic layer;
• and a wide-band-gap intrinsic layer located on the surface of the side of the bottom intrinsic layer facing away from the semiconductor substrate layer, the band gap of the wide-band-gap intrinsic layer is greater than that of the bottom intrinsic layer;
• the wide-band-gap intrinsic layer comprises a first sub-wide-band-gap intrinsic layer to an Nth sub-wide-band-gap intrinsic layer, and N is an integer greater than or equal to 2;
• a kth sub-wide-band-gap intrinsic layer is located between the k+1th sub-wide-band-gap intrinsic layer and the semiconductor substrate layer;
• k is an integer greater than or equal to 1 and less than or equal to N−1;
• for the intrinsic semiconductor composite layer located on a front side of the semiconductor substrate layer, a refractive index of the k+1th sub-wide-band-gap intrinsic layer in the intrinsic semiconductor composite layer is smaller than that of the kth sub-wide-band-gap intrinsic layer.