skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Optically enhanced photon recycling in mechanically stacked multijunction solar cells

Journal Article · · IEEE Journal of Photovoltaics
 [1];  [1];  [1];  [2];  [1];  [3];  [4];  [1];  [1];  [1];  [1];  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Univ. Politecnica de Madrid (Spain)
  3. Arizona State Univ., Tempe, AZ (United States)
  4. Boeing-Spectrolab, Sylmar, CA (United States)
+ Show Author Affiliations

Multijunction solar cells can be fabricated by mechanically bonding together component cells that are grown separately. Here, we present four-junction four-terminal mechanical stacks composed of GaInP/GaAs tandems grown on GaAs substrates and GaInAsP/GaInAs tandems grown on InP substrates. The component cells were bonded together with a low-index transparent epoxy that acts as an angularly selective reflector to the GaAs bandedge luminescence, while simultaneously transmitting nearly all of the subbandgap light. As determined by electroluminescence measurements and optical modeling, the GaAs subcell demonstrates a higher internal radiative limit and, thus, higher subcell voltage, compared with GaAs subcells without the epoxy reflector. The best cells demonstrate 38.8 ± 1.0% efficiency under the global spectrum at 1000 W/m2 and ~ 42% under the direct spectrum at ~100 suns. As a result, eliminating the series resistance is the key challenge for further improving the concentrator cells.

Research Organization:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
1237302
Report Number(s):
NREL/JA-5J00-64445
Journal Information:
IEEE Journal of Photovoltaics, Vol. 6, Issue 1; Related Information: IEEE Journal of Photovoltaics; ISSN 2156-3381
Publisher:
IEEECopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 31 works
Citation information provided by
Web of Science

Cited By (6)

GaSb-Based Solar Cells for Full Solar Spectrum Energy Harvesting journal July 2017
Measurement of strong photon recycling in ultra-thin GaAs n/p junctions monolithically integrated in high-photovoltage vertical epitaxial heterostructure architectures with conversion efficiencies exceeding 60% journal December 2016
Experimental Determination of Power Losses and Heat Generation in Solar Cells for Photovoltaic-Thermal Applications journal August 2018
Raising the one-sun conversion efficiency of III–V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions journal August 2017
Electroluminescent refrigeration by ultra-efficient GaAs light-emitting diodes journal May 2018
Impact of nanometer air gaps on photon recycling in mechanically stacked multi-junction solar cells journal January 2019

Similar Records

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
four-junction
GaInP
GaAs
GaInAsP
GaInAs
InP
subcell voltage
efficiency
series resistance
multijunction solar cell
mechanical stack
photon recycling
luminescent coupling
III-V solar cell