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

J. H. Ermer, R. K. Jones, P. Hebert, P. Pien, R. R. King, D. Bhusari, R. Brandt, O. Al-Taher, C. Fetzer, G. S. Kinsey, N. Karam

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Multijunction solar cells based on III-V semiconductors, having recently demonstrated 43.5, remain the worlds most efficient solar cells, and the preferred technology in point-focus and dense-array concentrator photovoltaic (CPV) system architectures. The year 2011 proved to be a pivotal year for CPV technology, with multiple power plant installations in the megawatt to tens of megawatt scale. Spectrolab is working closely with CPV system manufacturers to provide a reliable and well-characterized cell technology, in volumes commensurate with this increasing demand. The evolutionary C3MJ+ and the C4MJ cell technologies are the latest in a sequence of CPV solar cell designs, with conversion efficiencies approaching or greater than 40%. Both technologies have completed detailed characterization and qualification programs, including accelerated laboratory and (for C4MJ) on-sun reliability testing, and have entered into high volume production at Spectrolabs manufacturing facility in Sylmar, CA. The metamorphic C4MJ technology affords new opportunities to optimize cell designs, taking into consideration both the spectral optical transmittance of a particular CPV system and the installation sites average solar resource over a typical meteorological year.

Original languageEnglish (US)
Article number6132397
Pages (from-to)209-213
Number of pages5
JournalIEEE Journal of Photovoltaics
Issue number2
StatePublished - 2012
Externally publishedYes


  • Concentrator photovoltaics
  • III-V semiconductor materials
  • multijunction solar cells
  • photovoltaic cells
  • spectral response

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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