Measurement of high efficiency 1 cm2 AlGaInP/InGaAs/Ge solar cells with embedded InAs quantum dots at up to 1000 suns continuous concentration

Large commercial-grade 1 cm² quantum dot enhanced triple-junction AlGaInP/InGaAs/Ge solar cells were characterized using high-concentration flash and continuous-illumination solar simulators. Cyrium Technologies Incorporated (Cyrium™) routinely achieves >40% efficiency under ~500 suns flash illumination at 25°C using its QDEC™ product line based on this design. For this research project, Cyrium used its Application-Specific Concentrator Cell (ASCC) program to design and manufacture CPV cells with such quantum dot layers in the middle sub-cell of a triple-junction configuration. The high quality of the dislocation-free quantum dot layers used in such structures has been confirmed by photoluminescence, transmission electron microscopy, and quantum efficiency measurements. Receiver devices have been successfully tested up to ~950 suns of continuous illumination, producing currents >13 A from a 1 cm² cell. Continuous-illumination testing produced temperatures reaching >90°C above ambient at solar concentrations of >800 suns under some thermal coupling conditions. As a result, ASCC cells that achieved >38% efficiency at standard test conditions of 25°C under flash solar simulators measured 34-37% at high operating temperature under continuous illumination of up to 800 suns with the thermal resistance of the assembly used. These results show that it is essential to develop rigorous thermal management in a real-world concentrator system, for which continuous solar simulators are invaluable tools for testing prior to field deployment.