Chlorine activated stacking fault removal_Nature Comms_s41467-021-25063-y.pdf (4.04 MB)

Chlorine activated stacking fault removal mechanism in thin film CdTe solar cells: the missing piece

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journal contribution
posted on 06.09.2021, 11:08 by Peter Hatton, Michael Watts, Ali AbbasAli Abbas, Michael WallsMichael Walls, Roger SmithRoger Smith, Pooja GoddardPooja Goddard
The conversion efficiency of as-deposited, CdTe solar cells is poor and typically less than 5%. A CdCl2 activation treatment increases this to up to 22%. Studies have shown that stacking faults (SFs) are removed and the grain boundaries (GBs) are decorated with chlorine. Thus, SF removal and device efficiency are strongly correlated but whether this is direct or indirect has not been established. Here we explain the passivation responsible for the increase in efficiency but also crucially elucidate the associated SF removal mechanism. The effect of chlorine on a model system containing a SF and two GBs is investigated using density functional theory. The proposed SF removal mechanisms are feasible at the 400 ∘C treatment temperature. It is concluded that the efficiency increase is due to electronic effects in the GBs while SF removal is a by-product of the saturation of the GB with chlorine but is a key signal that sufficient chlorine is present for passivation to occur.

Funding

EPSRC Studentship 1801035

History

School

  • Mechanical, Electrical and Manufacturing Engineering
  • Science

Department

  • Chemistry
  • Mathematical Sciences

Research Unit

  • Centre for Renewable Energy Systems Technology (CREST)

Published in

Nature Communications

Volume

12

Issue

1

Publisher

Springer Nature

Version

VoR (Version of Record)

Rights holder

© The Authors

Publisher statement

This is an Open Access Article. It is published by Springer Nature under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0). Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/

Acceptance date

12/07/2021

Publication date

2021-08-23

Copyright date

2021

eISSN

2041-1723

Language

en

Depositor

Prof Michael Walls. Deposit date: 1 September 2021

Article number

4938

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