Impact of metastable defect structures on carrier recombination in solar cells

Seán R. Kavanagh; David O. Scanlon; Aron Walsh; Christoph Freysoldt

doi:10.1039/d2fd00043a

Impact of metastable defect structures on carrier recombination in solar cells

Seán R. Kavanagh^*, David O. Scanlon, Aron Walsh, Christoph Freysoldt

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

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Abstract

The efficiency of a solar cell is often limited by electron-hole recombination mediated by defect states within the band gap of the photovoltaic (PV) semiconductor. The Shockley-Read-Hall (SRH) model considers a static trap that can successively capture electrons and holes. In reality however, true trap levels vary with both the defect charge state and local structure. Here we consider the role of metastable structural configurations in capturing electrons and holes, taking the tellurium interstitial in CdTe as an illustrative example. Consideration of the defect dynamics, and symmetry-breaking, changes the qualitative behaviour and activates new pathways for carrier capture. Our results reveal the potential importance of metastable defect structures in non-radiative recombination, in particular for semiconductors with anharmonic/ionic-covalent bonding, multinary compositions, low crystal symmetries or highly-mobile defects.

Original language	English
Pages (from-to)	339-356
Number of pages	18
Journal	Faraday Discussions
Volume	239
Early online date	11 Apr 2022
DOIs	https://doi.org/10.1039/d2fd00043a
Publication status	Published - 1 Oct 2022

Bibliographical note

Funding Information:
Seán R. Kavanagh acknowledges the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (CDT-ACM) (EP/S023259/1) for funding a PhD studentship, as well as the Max-Planck-Institut für Eisenforschung and the Thomas Young Centre for funding a research visit through the ‘Coffee with Max Planck’ and Junior Research Fellowship awards. DOS acknowledges support from the EPSRC (EP/N01572X/1) and from the European Research Council, ERC (Grant No. 758345). AW acknowledges support from a National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (2018R1C1B6008728). We acknowledge the use of the UCL Kathleen High Performance Computing Facility (Kathleen@UCL), the Imperial College Research Computing Service, and associated support services, in the completion of this work. Via membership of the UK’s HEC Materials Chemistry Consortium, which is funded by the EPSRC (EP/L000202, EP/R029431, EP/T022213), this work used the ARCHER2 UK National Supercomputing Service ( https://www.archer2.ac.uk ) and the UK Materials and Molecular Modelling (MMM) Hub (Thomas – EP/P020194 & Young – EP/T022213).

Publisher Copyright:
© 2022 The Royal Society of Chemistry.

ASJC Scopus subject areas

Physical and Theoretical Chemistry

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Cite this

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title = "Impact of metastable defect structures on carrier recombination in solar cells",

abstract = "The efficiency of a solar cell is often limited by electron-hole recombination mediated by defect states within the band gap of the photovoltaic (PV) semiconductor. The Shockley-Read-Hall (SRH) model considers a static trap that can successively capture electrons and holes. In reality however, true trap levels vary with both the defect charge state and local structure. Here we consider the role of metastable structural configurations in capturing electrons and holes, taking the tellurium interstitial in CdTe as an illustrative example. Consideration of the defect dynamics, and symmetry-breaking, changes the qualitative behaviour and activates new pathways for carrier capture. Our results reveal the potential importance of metastable defect structures in non-radiative recombination, in particular for semiconductors with anharmonic/ionic-covalent bonding, multinary compositions, low crystal symmetries or highly-mobile defects.",

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Impact of metastable defect structures on carrier recombination in solar cells

Abstract

Bibliographical note

ASJC Scopus subject areas

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