Case 11367

Light trapping in thin film solar cells using textured photonic crystal

Keywords:

Photonic crystal, backside reflector structure, silicon solar cell, optical path length, light trapping, distributed Bragg reflector, photoactive region, quantum efficiency

Applications:

Photonic microstructures used in conjunction with thin film silicon solar cells

Problem:

Light trapping in absence of electron/hole pair recombination from presence of p-n junction in silicon

Technology:

We present a photonic crystal coupled to the photoactive region of a solar cell, wherein the photonic crystal includes a distributed Bragg reflector (DBR) for trapping light. The DBR grating can be developed using a practical fabrication process for silicon grating DBRs with CMOS compatibility on a silicon substrate. This photonic microstructure is used in conjunction with thin film silicon solar cells in order to enhance cell efficiency. This structure increases the optical path length of escaping photons by creating anomalous refraction effects.

Advantages:
  • Sustains high light-absorbing capability while reducing film thickness
  • Enhances optical path length
  • Increases solar cell efficiency
  • Maximizes open-circuit voltage

Inventors:
  • Professor Lionel Kimerling(Department of Materials Science and Engineering, MIT)
  • Yasha Yi (Materials Processing Center, MIT)
  • Xiaoman Duan (Department of Materials Science and Engineering, MIT)
  • Lirong Zeng (Department of Materials Science and Engineering, MIT)

Intellectual Property:

U.S. Patent No. 7,482,532, issued January 27, 2009

Publications:

N/A

Last revised:November 5, 2010

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