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Title: 100-period InGaAsP/InGaP superlattice solar cell with sub-bandgap quantum efficiency approaching 80%

Here, InGaAsP/InGaP quantum well (QW) structures are promising materials for next generation photovoltaic devices because of their tunable bandgap (1.50-1.80 eV) and being aluminum-free. However, the strain-balance limitations have previously limited light absorption in the QW region and constrained the external quantum efficiency (EQE) values beyond the In 0.49Ga 0.51P band-edge to less than 25%. In this work, we show that implementing a hundred period lattice matched InGaAsP/InGaP superlattice solar cell with more than 65% absorbing InGaAsP well resulted in more than 2x improvement in EQE values than previously reported strain balanced approaches. In addition, processing the devices with a rear optical reflector resulted in strong Fabry-Perot resonance oscillations and the EQE values were highly improved in the vicinity of these peaks, resulting in a short circuit current improvement of 10% relative to devices with a rear optical filter. These enhancements have resulted in an InGaAsP/InGaP superlattice solar cell with improved peak sub-bandgap EQE values exceeding 75% at 700 nm, an improvement in the short circuit current of 26% relative to standard InGaP devices, and an enhanced bandgap-voltage offset (W oc) of 0.4 V.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [3]
  1. North Carolina State Univ., Raleigh, NC (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. North Carolina State Univ., Raleigh, NC (United States)
Publication Date:
Report Number(s):
NREL/JA-5J00-70132
Journal ID: ISSN 0003-6951
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 111; Journal Issue: 8; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; band gap; solar cells; photodetectors; superlattices; metalloids
OSTI Identifier:
1393377
Alternate Identifier(s):
OSTI ID: 1376975