Detailed Balance Efficiency of 1310 nm Multijunction Photonic Power Converters

We present modeled detailed balance efficiency of multijunction photonic power converters operating at 1310 nm at a laser intensity of 5.88× 10
⁵
W/m
²
, corresponding to our test laser power and cell size, in two scenarios: (1) with an absorbing substrate and (2) with a perfect specular back reflector. We show that, in the radiative limit, efficiency increases as a function of number of junctions in the case of an absorbing substrate. In this case, efficiency can reach as high as 69% with 15 junctions. In the case of a perfect specular back reflector, efficiency reaches more than 75% and is not sensitive to the number of junctions. This insensitivity allows freedom in future device design.