Hairy Solar Panels Absorb More Light

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Hairy Solar Panels Absorb More Light
Ted Sanders tdsander_at_ucsd.edu Professor Ed
Yu ety_at_ece.ucsd.edu

• Nanowire Solar Cells
• I simulated light absorption of core-shell
  nanowire solar cells, finding optimal nanowire
  lengths, diameters, and spacings. The optimized
  nanowire solar cell showed improved absorption
  relative to standard, thin-film solar cells.
• Results
• Nanowires reflect much less light than thin
  films, but let lots of long wavelength light pass
  through
• Longer nanowires can absorb longer wavelengths,
  but have lower collection efficiency
• Thicker nanowires can also absorb longer
  wave-lengths, but at the expense of shorter
  wavelengths
• Dense arrays of nanowires reflect light and
  sparse arrays let light through, so moderate
  spacing is best
• More core absorbs more photons, while more shell
  collects more energy per photon
• Conclusion
• Simulations show that, with their impeccable
  visible absorption, optimized nanowires can
  absorb 69 of sunlight, surpassing thin films.
  Nanowires are a promising solar technology, with
  potentially both lower costs and higher
  efficiency.

Appearing darker, the nanowire cell absorbs more
visible light than the thin film cell.
Sunlight spectrum
Nanowires absorb 69 of sunlight
Real nanowires
Simulated nanowires
Thin film absorbs 46 of sunlight
Nanowires
Thin Film
100
100
Transmission increases at long wavelengths
Absorption is near perfect at low wavelengths
Absorption drops off at long wavelengths
Reflection is high across all wavelengths
Reflection is low across all wavelengths
Transmission increases at long wavelengths
0
0
1200
1200
300
300