Rapid Recombination by Cadmium Vacancies in CdTe

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

doi:10.1021/acsenergylett.1c00380

Rapid Recombination by Cadmium Vacancies in CdTe

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

^*Corresponding author for this work

Chemistry

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

27 Citations (Scopus)

20 Downloads (Pure)

Abstract

CdTe is currently the largest thin-film photovoltaic technology. Non-radiative electron-hole recombination reduces the solar conversion efficiency from an ideal value of 32% to a current champion performance of 22%. The cadmium vacancy (V_Cd) is a prominent acceptor species in p-type CdTe; however, debate continues regarding its structural and electronic behavior. Using ab initio defect techniques, we calculate a negative-U double-acceptor level for V_Cd, while reproducing the V_Cd^1- hole-polaron, reconciling theoretical predictions with experimental observations. We find the cadmium vacancy facilitates rapid charge-carrier recombination, reducing maximum power-conversion efficiency by over 5% for untreated CdTe- A consequence of tellurium dimerization, metastable structural arrangements, and anharmonic potential energy surfaces for carrier capture.

Original language	English
Pages (from-to)	1392-1398
Number of pages	7
Journal	ACS Energy Letters
Volume	6
Issue number	4
Early online date	19 Mar 2021
DOIs	https://doi.org/10.1021/acsenergylett.1c00380
Publication status	Published - 9 Apr 2021

Bibliographical note

Funding Information:
We thank Dr. Anna Lindström for valuable discussions regarding polaronic structures for cadmium vacancies, and Dr. Sungyhun Kim for assistance with CarrierCapture.jl calculations. S.R.K. acknowledges the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (CDT-ACM)(EP/S023259/1) for funding a Ph.D. studentship. We acknowledge the use of the UCL Grace High Performance Computing Facility (Grace@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 ARCHER UK National Supercomputing Service ( www.archer.ac.uk and the UK Materials and Molecular Modelling (MMM) Hub (Thomas EP/P020194 and Young EP/T022213).

Publisher Copyright:
© 2021 American Chemical Society.

ASJC Scopus subject areas

Chemistry (miscellaneous)
Renewable Energy, Sustainability and the Environment
Fuel Technology
Energy Engineering and Power Technology
Materials Chemistry

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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KavanaghS2021RapidFinal published version, 2.03 MBLicence: Creative Commons: Attribution (CC BY)

Cite this

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abstract = "CdTe is currently the largest thin-film photovoltaic technology. Non-radiative electron-hole recombination reduces the solar conversion efficiency from an ideal value of 32% to a current champion performance of 22%. The cadmium vacancy (VCd) is a prominent acceptor species in p-type CdTe; however, debate continues regarding its structural and electronic behavior. Using ab initio defect techniques, we calculate a negative-U double-acceptor level for VCd, while reproducing the VCd1- hole-polaron, reconciling theoretical predictions with experimental observations. We find the cadmium vacancy facilitates rapid charge-carrier recombination, reducing maximum power-conversion efficiency by over 5% for untreated CdTe- A consequence of tellurium dimerization, metastable structural arrangements, and anharmonic potential energy surfaces for carrier capture.",

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AB - CdTe is currently the largest thin-film photovoltaic technology. Non-radiative electron-hole recombination reduces the solar conversion efficiency from an ideal value of 32% to a current champion performance of 22%. The cadmium vacancy (VCd) is a prominent acceptor species in p-type CdTe; however, debate continues regarding its structural and electronic behavior. Using ab initio defect techniques, we calculate a negative-U double-acceptor level for VCd, while reproducing the VCd1- hole-polaron, reconciling theoretical predictions with experimental observations. We find the cadmium vacancy facilitates rapid charge-carrier recombination, reducing maximum power-conversion efficiency by over 5% for untreated CdTe- A consequence of tellurium dimerization, metastable structural arrangements, and anharmonic potential energy surfaces for carrier capture.

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Rapid Recombination by Cadmium Vacancies in CdTe

Abstract

Bibliographical note

ASJC Scopus subject areas

UN SDGs

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