Band versus Polaron: Charge Transport in Antimony Chalcogenides

Xinwei Wang, Alex M. Ganose, Seán R. Kavanagh, Aron Walsh

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Antimony sulfide (Sb2S3) and selenide (Sb2Se3) are emerging earth-abundant absorbers for photovoltaic applications. Solar cell performance depends strongly on charge-carrier transport properties, but these remain poorly understood in Sb2X3 (X = S, Se). Here we report band-like transport in Sb2X3, determined by investigating the electron-lattice interaction and theoretical limits of carrier mobility using first-principles density functional theory and Boltzmann transport calculations. We demonstrate that transport in Sb2X3 is governed by large polarons with moderate Fröhlich coupling constants (α ≈ 2), large polaron radii (extending over several unit cells), and high carrier mobility (an isotropic average of >10 cm2 V-1 s-1 for both electrons and holes). The room-temperature mobility is intrinsically limited by scattering from polar phonon modes and is further reduced in highly defective samples. Our study confirms that the performance of Sb2X3 solar cells is not limited by intrinsic self-trapping.

Original languageEnglish
Pages (from-to)2954-2960
Number of pages7
JournalACS Energy Letters
DOIs
Publication statusAccepted/In press - 2022

Bibliographical note

Funding Information:
X.W. thanks Jarvist M. Frost, Yuchen Fu, and Ye Yang for valuable discussions. We are grateful to the UK Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1 and EP/T022213/1). X.W. acknowledges Imperial College London for a President’s Ph.D. Scholarship. A.M.G. was supported by EPSRC Fellowship EP/T033231/1. S.R.K. acknowledges the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (CDT-ACM)(EP/S023259/1) for a Ph.D. studentship.

Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.

All Science Journal Classification (ASJC) codes

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

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