Si cells with III-V multijunction cells

A solar conversion assembly comprising:

• a) a type III-V multiple cell stack solar cell device, the type III-V multiple cell stack solar cell device comprising a germanium solar cell device and having a first light receiving surface extending in a first plane;
• b) a silicon solar cell device located separately from the type III-V multiple cell stack solar cell device, the silicon solar cell device having a second light receiving surface extending in a second plane different from the first plane, wherein the first and second planes intersect;
• c) a planar band splitting device located relative to the type III-V multiple cell stack solar cell device and the silicon solar cell device to split light falling on the planar band splitting device into a first light component and a second light component, the first light component having only a first wavelength band and the second light component having a plurality of wavelength bands having wavelengths that are less than and greater than the first wavelength band, wherein the planar band splitting device is located between the first light receiving surface and the second light receiving surface such as to direct the first light component to the second light receiving surface of the silicon solar cell device and direct the second light component to the first light receiving surface of the type III-V multiple cell stack solar cell device.