Solar cells

A solar cell, comprising:

• an N-type silicon substrate having a first surface and a second surface,
• a tunnel passivation structure and a first passivation and anti-reflection film formed on the first surface,
• a boron-doped emitter structure layer formed on the second surface, wherein the emitter structure layer includes a first emitter layer and a second emitter region, wherein the junction depth of the first emitter layer is smaller than that of the second emitter region, the boron doping concentrations of the first emitter layer and the second emitter region vary in the depth direction, respectively, the highest boron doping concentration of the first emitter layer is greater than that of the second emitter region, and the total boron doping amount of the first emitter layer is less than that of the second emitter region,
• a second passivation and anti-reflection film formed on the emitter structure layer,
• a first electrode configured to be in electrical contact with the second emitter region,
• a second electrode configured to be in electrical contact with the tunnel passivation structure,
• wherein within the range of a depth of 0.02-0.6 μm from the surface of the first emitter layer in the ECV doping curve of the first emitter layer, the difference between the highest boron doping concentration and the lowest boron doping concentration in the first emitter layer is greater than 1 orders of magnitude, and within the range of 0.05-0.7 μm from the surface of the second emitter region in the ECV doping curve of the second emitter region, the difference between the highest boron doping concentration and the lowest boron doping concentration in the second emitter region is less than 1 order of magnitude.