Exceeding 20% Efficiency with in situ Group V Doping in Polycrystalline CdTe Solar Cells

Wyatt Metzger, Eric Colegrove, John Moseley, Craig Perkins, Chun Sheng Jiang, Darius Kuciauskas, David Albin, Mowafak Al-Jassim, S. Grover, D. Lu, X. Li, R. Mallick, W. Zhang, R. Malik, J. Kephart, G. Xiong, M. Gloeckler

Research output: Contribution to journalArticlepeer-review

246 Scopus Citations

Abstract

CdTe-based solar technology has achieved one of the lowest levelized costs of electricity among all energy sources as well as state-of-the-art field stability. Yet, there is still ample headroom to improve. For decades, mainstream technology has combined fast CdTe deposition with a CdCl2 anneal and Cu doping. The resulting defect chemistry is strongly compensated and limits the useful hole density to ~1014 cm−3, creating a ceiling for fill factor, photovoltage and efficiency. In addition, Cu easily changes energy states and diffuses spatially, creating a risk of instabilities that must be managed with care. Here, we demonstrate a significant shift by doping polycrystalline CdSexTe1 − x and CdTe films with As while removing Cu entirely from the solar cell. The absorber majority-carrier density is increased by orders of magnitude to 1016–1017 cm−3 without compromising the lifetime, and is coupled with a high photocurrent greater than 30 mA cm−2. We demonstrate pathways for fast dopant incorporation in polycrystalline thin films, improved stability and 20.8% solar cell efficiency.

Original languageAmerican English
Pages (from-to)837-845
Number of pages9
JournalNature Energy
Volume4
Issue number10
DOIs
StatePublished - 1 Oct 2019

Bibliographical note

Publisher Copyright:
© 2019, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.

NREL Publication Number

  • NREL/JA-5K00-73704

Keywords

  • applied physics
  • condensed-matter physics
  • device physics
  • electronics
  • photonics
  • solar energy

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