Temperature coefficients of multijunction solar cells

Temperatures coefficients measured in solar simulators with those measured under AM0 solar illumination are compared to illustrate the challenges in making these measurements. It is shown that simulator measurements of the short-circuit current (∂J_SC/∂T) are inaccurate due to the mismatch between the solar spectrum and the simulators at the bandgaps of the solar cells. Especially susceptible to error is the ∂J_SC/∂T of cells which are components in monolithic multijunctions solar cells, such as GaAs filtered by 1.93 eV AlGaAs, which has an AM0 coefficient of 6.82 μA/cm²/°C, compared to a Xenon simulator coefficient of 22.2 μA/cm²/°C