Dependence of multijunction optimal gaps on spectral variability and other environmental and device parameters
Jose M Ripalda1, Jeronimo Buencuerpo1,2, Ivan Garcia3
1IMN - CSIC, Madrid, Spain
/2Now at NREL, Golden, CO, United States
/3IES - UPM, Madrid, Spain

We present a method to calculate the yearly energy production of multijunctions including spectral variations. We use it to find the optimal band gaps yielding maximum energy production. The band gaps found are different to those previously reported when using the standard efficiency as the optimization target. We also discuss the effects of changing parameters such as the external radiative efficiency, series resistance, subcell thickness, temperatures, and location. We find that certain band gap combinations are nearly optimal in a broad range of locations under very different atmospheric conditions.