Prospects of hybrid bifacial four-junction solar cell for concentrating photovoltaics

A hybrid monolithic four-junction solar cell composed of GaInP/Ga(In) As/Ge electricity-generating linear arrays arranged in an n-α-Si:H/(p)c-Si:(Ga)/p-a-Si:H bifacial photoactive heat-dissipating substrate was investigated as part of a concentrator photovoltaic module. The module provides a specific power output ≤ 500 W/m2 (AM0, 1367 W/m2) at the beginning of life, taking into account the converted the Earth albedo. The damage coefficient of effective diffusion length for minority charge carriers in the photoactive heat-dissipating substrate has been determined as KL = 1·10−11 at 1 MeV electron fluence up to 1·1015cm−2. The anticipated lifespan of the monolithic hybrid four-junction solar cell in the module on geostationary orbit is projected to be ≤ 15 years. Accounting for the albedo effects, it does not only increase the generated electrical power but also reduces thermal stress on the spacecraft’s solar panel.