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Advanced Ultra High Performance InP Solar Cells

National Renewable Energy Laboratory

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Technology Marketing Summary

Indium Phosphide (InP) is a semiconductor compound typically used in solar cells and high speed electronics. InP has a number of performance benefits compared to other III-V materials due to its higher mean and peak saturation velocities, which result in optoelectronic devices with higher frequency. InP solar cells, with a bandgap of 1.34 eV and high absorption levels, have a strong potential of reaching the Shockley-Queisser theoretical efficiency level of approximately 33%. Despite this potential, however, the efficiency levels of InP solar cells have previously been recorded at 21.9%.


Researchers at NREL have developed a method to increase the efficiency levels of InP solar cells to 24.2% in the AM1.5G spectrum and 22.1% in the AMO spectrum. These record-breaking efficiency levels were obtained by reducing non-radiative recombination losses at the absorber layer interfaces to a minimal level by employing dual minority-carrier confinement schemes.  In the n-on-p architecture, for instance, a highly-doped front-surface confinement layer is grown on top of the InP emitter layer, creating a potential barrier between the highly-doped surface layer and the lightly-doped emitter. For confinement of carriers from the p-type InP layer, a lattice-matched AlGaInSbAsP alloy is utilized. Additionally, the invention outlines optical-confinement schemes to improve the cell efficiency even further.

The new efficiency levels achieved by the NREL researchers have set a new world record for InP solar cell efficiency and were achieved at 25 degrees C at a one sun intensity level.

  • New world record for efficiency levels of InP solar cells
  • Reduces non-radiative recombination losses
Applications and Industries
  • Solar Energy
  • Solar Cells and Systems
  • Transistors
  • InP optoelectronic devices
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 9,590,131
Systems and methods for advanced ultra-high-performance InP solar cells
Systems and Methods for Advanced Ultra-High-Performance InP Solar Cells are provided. In one embodiment, an InP photovoltaic device comprises: a p-n junction absorber layer comprising at least one InP layer; a front surface confinement layer; and a back surface confinement layer; wherein either the front surface confinement layer or the back surface confinement layer forms part of a High-Low (HL) doping architecture; and wherein either the front surface confinement layer or the back surface confinement layer forms part of a heterointerface system architecture.
National Renewable Energy Laboratory 03/07/2017
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
ROI 13-42PrototypeAvailable06/23/201606/23/2016

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To: Bill Hadley<>