Status of C3MJ+ and C4MJ production concentrator solar cells at Spectrolab

Multijunction solar cells based on III-V semiconductors remain the most efficient solar cells in the world and are the preferred technology in point-focus and dense-array CPV system architectures. 2011 will prove a pivotal year for CPV technology, with multiple system suppliers installing power plants in the MW to 10's of MW scale. Spectrolab is working closely with CPV system manufacturers to provide a reliable and well-characterized cell technology in volumes commensurate with this demand. The C3MJ+ and C4MJ cell technologies are the latest in an evolutionary sequence of CPV solar cell designs, with conversion efficiencies approaching, or greater than 40%. Both device technologies are completing detailed characterization and qualification programs and both technologies have entered high volume production at Spectrolab in Sylmar, CA. Spectrolab is pursuing an aggressive development roadmap to further improve performance and reliability of next-generation cell designs. This paper reviews in detail the characterization of C3MJ+ and C4MJ production CPV cell properties, investigation of reliability in both laboratory and on-sun environments, and the technology roadmap for future improvements.