Designing bottom silicon solar cells for multijunction devices

Ibraheem Almansouri, Stephen Bremner, Anita Ho-Baillie, Hamid Mehrvarz, Xiaojing Hao, Gavin Conibeer, Tyler J. Grassman, John A. Carlin, Alexander Haas, Steven A. Ringel, Martin A. Green

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

We report on efforts to design high-efficiency silicon homojunction subcells for use in multijunction stack devices. Both simulation and experimental works have been performed looking at a silicon solar cell under a truncated spectrum below 1.5 eV filtered by the upper layers in the multijunction stack. Good agreement is seen between the modeling and experimental results, identifying different emitter design requirements when the solar cell operates under a full or truncated spectrum. A well-passivated front surface, i.e., with low-interface surface recombination velocity, required a lightly doped emitter profile to maximize open-circuit voltage (VOC ), while a high-interface recombination surface requires a heavily doped for higher VOC values. The impact on short-circuit current density (JSC ) is found to be minimal, even with large variations in the interface recombination and emitter profiles. In a tandem stack, an interface with low- and high-interface recombination velocities would require lightly doped and intermediate-doped emitters, respectively, for maximum conversion efficiency (η).

Original languageEnglish
Article number7000526
Pages (from-to)683-690
Number of pages8
JournalIEEE Journal of Photovoltaics
Volume5
Issue number2
DOIs
Publication statusPublished - 1 Mar 2015
Externally publishedYes

Keywords

  • Active bottom silicon junction
  • interface recombination
  • multijunction solar cell
  • silicon substrate

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