This is the final published version. It first appeared at http://www.sciencedirect.com/science/article/pii/S0927024814003833#.The performance of InAs/GaAs quantum dot solar cells was investigated up to an optical concentration of
500-suns. A high temperature spacer layer between successive layers of quantum dots was used to
reduce the degradation in the open circuit voltage relative to a control device without quantum dots.
This improvement is explained using optical data while structural imaging of quantum dot stacks
confirm that the devices are not limited by strain. The evolution of the open circuit voltage as a function
of number of suns concentration was observed to be nearly ideal when compared with a high
performance single junction GaAs solar cell. Analysis of Suns-Voc measurements reveal diode ideality
factors as low as 1.16 which is indicative of a low concentration of defects in the devices.The authors acknowledge financial support from the European
Union under the Seventh Framework Programme under a contract
for an Integrated Infrastructure Initiative. Reference 312483 –
ESTEEM2
