External quantum efficiency of bifacial HIT solar cells

It is shown that the use of both sides of solar cells created with the heterojunction technology makes possible an increase in the solar-cell efficiency. The difference in illumination of the front and back sides is associated with transformation of the blue part of the spectrum, which is shown by the example of the spectral dispersion of the quantum efficiency. The average difference between the quantum efficiency for both sides is $\sim$11%. The short-circuit current density with the power of the solar spectrum at sea level from 400 to 1100 nm is 36.3 mA/cm$^2$ for the front side and 32.7 mA/cm$^2$ for the back side. The decrease amounts to 9.7%.