Multijunction Solar Cells with Graded Buffer Bragg Reflectors

Ryan France (Inventor), John Geisz (Inventor), Pilar Espinet-Gonzalez (Inventor)

Research output: Patent


Distributed Bragg reflectors are incorporated into the compositionally graded buffers of metamorphic solar cells, adding functionality to the buffer without adding cost. The reflection aids in collection in subcells that are optically thin due to low diffusion length, high bulk recombination, radiation hardness, partially-absorbing quantum structures, or simply for cost savings. Performance enhancements are demonstrated in GaAs subcells with QWs, which is beneficial when GaAs is not the ideal bandgap.
Original languageAmerican English
Patent number11,205,734 B2
Filing date21/12/21
StatePublished - 2021

NREL Publication Number

  • NREL/PT-5900-81761


  • alternating Al4n layers
  • distributed Bragg reflector (DBR)
  • inverted metamorphic multijunction (IMM) device
  • metamorphic layer


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