Mechanically stacked four-junction concentrator solar cells

Steiner, Myles A. and Geisz, John F. and Ward, J. Scott and García Vara, Iván and Friedman, Daniel J. and King, Richard R. and Chiu, Philip T. and France, Ryan M. and Duda, Anna and Olavarria, Waldo J. and Young, Michelle and Kurtz, Sarah R. (2015). Mechanically stacked four-junction concentrator solar cells. In: "42nd Photovoltaic Specialist Conference (PVSC 2015)", 14/06/2015 - 19/06/2015, New Orleans, LA, EE.UU. pp. 1-3.


Title: Mechanically stacked four-junction concentrator solar cells
  • Steiner, Myles A.
  • Geisz, John F.
  • Ward, J. Scott
  • García Vara, Iván
  • Friedman, Daniel J.
  • King, Richard R.
  • Chiu, Philip T.
  • France, Ryan M.
  • Duda, Anna
  • Olavarria, Waldo J.
  • Young, Michelle
  • Kurtz, Sarah R.
Item Type: Presentation at Congress or Conference (Article)
Event Title: 42nd Photovoltaic Specialist Conference (PVSC 2015)
Event Dates: 14/06/2015 - 19/06/2015
Event Location: New Orleans, LA, EE.UU
Title of Book: 42nd Photovoltaic Specialist Conference (PVSC 2015)
Date: 2015
Freetext Keywords: III-V solar cell; Mechanical stack; Multijunction solar cell; Photon recycling
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Electrónica Física
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Multijunction solar cells can be fabricated by bonding together component cells that are grown separately. Because the component cells are each grown lattice-matched to suitable substrates, this technique allows alloys of different lattice constants to be combined without the structural defects introduced when using metamorphic buffers. Here we present results on the fabrication and performance of four-junction mechanical stacks composed of GaInP/GaAs and GaInAsP/GaInAs tandems, grown on GaAs and InP substrates, respectively. The two tandems were bonded together with a lowindex, transparent epoxy that acts as an omni-directional reflector to the GaAs bandedge luminescence, while simultaneously transmitting nearly all of the sub-bandgap light. As determined by electroluminescence measurements and optical modeling, the GaAs subcell demonstrates a higher internal radiative limit and thus higher subcell voltage, compared with GaAs subcells without enhanced internal optics; all four subcells exhibit excellent material quality. The device was fabricated with four contact terminals so that each tandem can be operated at its maximum power point, which raises the cumulative efficiency and decreases spectral sensitivity. Efficiencies exceeding 38% at one-sun have been demonstrated. Eliminating the series resistance is the key challenge for the concentrator cells. We will discuss the performance of one-sun and concentrator versions of the device, and compare the results to recently fabricated monolithic four-junction cells.

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Item ID: 42024
DC Identifier:
OAI Identifier:
DOI: 10.1109/PVSC.2015.7356151
Deposited by: Memoria Investigacion
Deposited on: 24 Jul 2016 11:28
Last Modified: 24 Jul 2016 11:28
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