The role of sodium as a surfactant and suppressor of non-radiative recombination at internal surfaces in Cu2 ZnSnS4
It is well-known that sodium improves the performance of Cu2ZnSnS4 (CZTS) devices, yet the mechanism of the enhancement is still not fully understood. This work aims to present a unified account of the relationships between grain boundaries in CZTS, sodium content at these boundaries, non-radiative recombination, and surfactant effects that produce large microstructural changes. Using temperature-dependent photoluminescence measurements, it is demonstrated that samples containing dramatically different grain sizes display identical radiative and non-radiative decay characteristics when sufficient sodium is present in the film. It is also shown that the sodium concentration needed to efficiently passivate non-radiative defects is significantly less that the quantity needed to obtain micrometer-sized CZTS grains. Finally, the high densities of donor-acceptor pairs that are observed in CZTS films appear to reside within the grains themselves, rather than at grain boundaries.
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- 4016 Materials engineering
- 3403 Macromolecular and materials chemistry
- 0915 Interdisciplinary Engineering
- 0912 Materials Engineering
- 0303 Macromolecular and Materials Chemistry
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Related Subject Headings
- 4016 Materials engineering
- 3403 Macromolecular and materials chemistry
- 0915 Interdisciplinary Engineering
- 0912 Materials Engineering
- 0303 Macromolecular and Materials Chemistry