Grain-Boundary Structural Relaxation in Sb2Se3 Thin-Film Photovoltaics

Lomas-Zapata, RA ORCID: 0000-0003-3996-7967, Mckenna, KP ORCID: 0000-0003-0975-3626, Ramasse, QM ORCID: 0000-0001-7466-2283, Williams, RE ORCID: 0000-0003-3788-9600, Phillips, LJ ORCID: 0000-0001-5181-1565, Durose, K ORCID: 0000-0003-1183-3211, Major, JD ORCID: 0000-0002-5554-1985 and Mendis, BG ORCID: 0000-0003-2334-2866 (2024) Grain-Boundary Structural Relaxation in Sb2Se3 Thin-Film Photovoltaics Prx Energy, 3 (1). 013006-. ISSN 2768-5608, 2768-5608

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Abstract

Grain boundaries play an important role in the efficiency of thin-film photovoltaics, where the absorber layer is invariably polycrystalline. Density-functional-theory simulations have previously identified a "self-healing"mechanism in Sb2Se3 that passivates the grain boundaries. During "self-healing,"extensive structural relaxation at the grain boundary removes the band-gap electronic defect states that give rise to high carrier recombination rates. In this work, lattice imaging in a transmission electron microscope is used to uncover evidence for the theoretically proposed structural relaxation in Sb2Se3. The strain measured along the [010] crystal direction is found to be dependent on the nature of the grain-boundary plane. For a (010) grain boundary, the strain and structural relaxation is minimal, since no covalent bonds are broken by termination of the grain. On the other hand, strains of up to approximately 4% extending approximately 2 nm into the grain interior are observed for a (041) grain boundary, where grain termination results in significant structural relaxation due to the ideal atomic coordination being disrupted. These results are consistent with theory and suggest that Sb2Se3 may have a high level of grain-boundary-defect tolerance.

Item Type:	Article
Uncontrolled Keywords:	40 Engineering, 3403 Macromolecular and Materials Chemistry, 4016 Materials Engineering, 34 Chemical Sciences
Divisions:	Faculty of Science & Engineering > School of Physical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	19 Mar 2024 10:20
Last Modified:	24 Jan 2026 04:49
DOI:	10.1103/PRXEnergy.3.013006
Open Access URL:	https://journals.aps.org/prxenergy/abstract/10.110...
Related Websites:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3179688
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