Si-based Parallel Multijunction Solar Cells for Solar Spectrum Splitting, High Efficiency Concentrating Photovoltaics

Technology #15192

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Inventors
Professor Lionel Kimerling
Department of Material Sciences and Engineering, MIT
External Link (photonics.mit.edu)
Xing Sheng
Department of Material Sciences and Engineering, MIT
Juejun Hu
Department of Material Sciences and Engineering, MIT
Jing Cheng
Department of Material Sciences and Engineering, MIT
Jifeng Liu
Department of Material Sciences and Engineering, MIT
Lirong Zeng
Department of Material Sciences and Engineering, MIT
Brian Albert
Department of Material Sciences and Engineering, MIT
Jurgen Michel
Department of Material Sciences and Engineering, MIT
Anuradha Agarwal
Department of Material Sciences and Engineering, MIT
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Methods and apparatus for concentrating photovoltaics

US Patent Pending 2014-0090686

Technique to increase solar cell efficiency by splitting solar light to multiple wavelength bands and directing each to optimized solar cells for that particular wavelength band.

Applications

The dominant application is concentrated photovoltaics.

Problem Addressed

Traditional solar cells with concentrating systems use expensive III-V or Ge substrates, require complicated film growth techniques for lattice matching and forming tunnel junctions, and necessitate current matching that is difficult to optimize for varying weather conditions.

Technology

This invention describes an integrated approach which splits the solar spectrum into different bands directed toward discrete solar cells with spectrally matched bandgaps.  This allows cells to be optimized independently.  For each discrete solar cell, a single crystalline thin film Ge cell can be grown on top of a Si substrate to be used as a virtual substrate, replacing the Ge substrate.

Advantages

  • Cost-savings compared to other spectrum splitting approaches
  • CMOS compatible
  • No longer a need for lattice and current matching
  • Flexibility in material choice based on bandgap considerations
  • Easy mounting
  • Reduced optical loss compared to physically mounting individual cells on a common substrate