Bifacial front and back side output

[nitinpanwar]

Why the back side and front side output power of a Bifacial module are different while the front and back side both are illuminated with 1000W/m2 at STC condition ?

[Bruno Wittmer]

Bifacial PV cells are not manufactured in a completely symmetrical way. The doping, metallization and passivation/texturing is different for both sides. This leads to different optical and electrical properties for the two sides, and thus different response for similar irradiance and temperature conditions.

This difference is expressed by the bifaciality factor, which is defined as the ratio between front and rear side response at same conditions. Typically, the bifaciality factor ranges between 70% and 95%.

[nitinpanwar]

Thanks Bruno Wittmer for sharing your view. :)