Ab initio thermodynamic model of Cu${}_2$ZnSnS${}_4$

Abstract

Thin-film solar cells based on the semiconductor Cu${}_2$ZnSnS${}_4$ (CZTS) are a promising candidate for Terawatt-scale renewable energy generation. While CZTS is composed of earth abundant and non-toxic elements, arranged in the kesterite crystal structure, there is a synthetic challenge to produce high-quality stoichiometric materials over large areas. We calculate the thermodynamic potentials of CZTS and its elemental and binary components based on energetic and vibrational data computed using density functional theory. These chemical potentials are combined to produce a thermodynamic model for the stability of CZTS under arbitrary temperatures and pressures, which provide insights into the materials chemistry. CZTS was shown to be thermodynamically stable with respect to its component elements and their major binary phases binaries under modest partial pressure of sulfur and temperatures below 1100K. Under near-vacuum conditions with sulfur partial pressures below 1 Pa decomposition into binaries including solid SnS becomes favourable, with a strongly temperature-dependent stability window.

arXiv commentThermodynamic model programs and supporting data are available at https://github.com/WMD-Bath/CZTS-model

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Cited by in corpus (5)

• Perspective: Theory and simulation of hybrid halide perovskites
• Lone-pair effect on carrier capture in Cu${}_2$ZnSnS${}_4$ solar cells
• A universal chemical potential for sulfur vapours
• Crystal structure optimisation using an auxiliary equation of state
• Role of electron-phonon coupling and thermal expansion on band gaps, carrier mobility, and interfacial offsets in kesterite thin-film solar cells