Enhanced Internal Reflectance of Emission in Solar Cells with Angle- And Energy-selective Reflectors

Eric Y. Chen, Sean J. Babcock, Nicholas P. Irvin, Richard R. King

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The open-circuit voltage of solar cells benefits from highly internally reflective surfaces on the front and rear of the cells that restrict radiative recombination current losses and lead to maximum device efficiency. While the back reflector reflects emitted photons broadly, an energy-selective front reflector is tailored to reflect photons with energies below the designed energy and can be energetically situated just above the solar cell absorber bandgap. Devices with an energy of restriction E_{R} > E_{g} show a maximum VOC analogous to blue-shifting the absorption and emission spectra to that of a solar cell with a bandgap E_{g}=E_{R}. Devices that incorporate both angle- and energy-selectivity benefit from reduced radiative recombination current losses due to etendue expansion loss reduction and reduced blackbody emission absorption, respectively. Resulting VOC gains of several hundred meV are expected for low-bandgap solar cells, corresponding with up to 15% absolute efficiency increase for \mathrm{E}_{g} < 0.70\ \mathrm{eV} and E_{R} between 1.1 and 1.2 eV.

Original languageEnglish (US)
Title of host publication2020 47th IEEE Photovoltaic Specialists Conference, PVSC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages7
ISBN (Electronic)9781728161150
StatePublished - Jun 14 2020
Event47th IEEE Photovoltaic Specialists Conference, PVSC 2020 - Calgary, Canada
Duration: Jun 15 2020Aug 21 2020

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371


Conference47th IEEE Photovoltaic Specialists Conference, PVSC 2020


  • angle restriction
  • blackbody emission
  • dielectric stacks
  • front reflector
  • photon recycling

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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