Characterization of Multiterminal Tandem Photovoltaic Devices and Their Subcell Coupling

John Geisz, William McMahon, Jeronimo Buencuerpo, Michelle Young, Michael Rienacker, Adele Tamboli, Emily Warren

Research output: Contribution to journalArticlepeer-review

11 Scopus Citations


Three-terminal (3T) and four-terminal (4T) tandem photovoltaic (PV) devices using various materials have been increasingly reported in the literature, but measurement standards are lacking. Here, multiterminal devices measured as functions of two load variables are characterized unambiguously as functions of three device voltages or currents on hexagonal plots. We demonstrate these measurement techniques using two GaInP/GaAs tandem solar cells, with a middle contact between the two subcells, as example 3T devices with both series-connected and reverse-connected subcells. Coupling mechanisms between the subcells are quantified within the context of a simple equivalent optoelectronic circuit. Electrical and optical coupling mechanisms are most clearly revealed using coupled dark measurements. These measurements are sensitive enough to observe very small luminescent coupling from the bottom subcell to the top subcell in the prototype 3T device. Quick simplified measurement techniques are also discussed within the context of the complete characterization.

Original languageAmerican English
Article numberArticle No. 100677
Number of pages19
JournalCell Reports Physical Science
Issue number12
StatePublished - 22 Dec 2021

Bibliographical note

Publisher Copyright:
© 2021 National Renewable Energy Laboratory, The Author(s)

NREL Publication Number

  • NREL/JA-5900-80101


  • coupling
  • four-terminal
  • III-V
  • luminescent
  • measurements
  • photovoltaic
  • solar cell
  • tandem
  • three-terminal


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