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Title: In-depth analysis of chloride treatments for thin-film CdTe solar cells

CdTe thin-film solar cells are now the main industrially established alternative to silicon-based photovoltaics. These cells remain reliant on the so-called chloride activation step in order to achieve high conversion efficiencies. Here, by comparison of effective and ineffective chloride treatments, we show the main role of the chloride process to be the modification of grain boundaries through chlorine accumulation, which leads an increase in the carrier lifetime. It is also demonstrated that while improvements in fill factor and short circuit current may be achieved through use of the ineffective chlorides, or indeed simple air annealing, voltage improvement is linked directly to chlorine incorporation at the grain boundaries. Lastly, this suggests that focus on improved or more controlled grain boundary treatments may provide a route to achieving higher cell voltages and thus efficiencies.
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  1. Univ. of Liverpool (United Kingdom). Stephenson Inst. for Renewable Energy and Dept. of Physics
  2. Umm Al-Qura Univ., Mecca (Saudi Arabia)
  3. Durham Univ. (United Kingdom). G.J. Russell Microscopy Facility, Dept. of Physics
  4. Univ. of Southampton (United Kingdom). School of Physics & Astronomy; Skolkovo Inst. of Science and Technology, Moscow (Russia)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  6. National Univ. of Singapore (Singapore)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; EP/J017361/1
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
14 SOLAR ENERGY; Materials for devices; Semiconductors; Solar cells
OSTI Identifier: