TY - JOUR
T1 - High temperature equilibrium of 3D and 2D chalcogenide perovskites
AU - Longo, Giulia
AU - Whalley, Lucy D.
AU - Holland, Adam
AU - Tiwari, Devendra
AU - Durose, Ken
AU - Hutter, Oliver S.
AU - Kayastha, Prakriti
N1 - Funding information: P.K. and L.D.W. thank Jonathan M. Skelton for discussions on Phonopy‐Spectroscopy. P.K. and G.L. acknowledge support from the UK Engineering and Physical Sciences Research Council (EPSRC) CDT in Renewable Energy Northeast Universities (ReNU) for funding through EPSRC Grant EP/S023836/1. The authors thank Horiba for the support with the Raman measurements. This work used the Oswald High Performance Computing facility operated by Northumbria University (UK). Via our membership of the UK's HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/R029431), this work used the ARCHER2 UK National Supercomputing Service.
PY - 2023/5/1
Y1 - 2023/5/1
N2 - Chalcogenide perovskites have been recently proposed as novel absorber materials for photovoltaic applications. BaZrS
3, the most investigated compound of this family, shows a high absorption coefficient, a bandgap of around 1.8 eV, and excellent stability. In addition to the 3D perovskite BaZrS
3, the Ba–Zr–S compositional space contains various 2D Ruddlesden–Popper phases Ba
n + 1Zr
nS
3n + 1 (with n = 1, 2, 3) which have recently been reported. Herein, it is shown that at high temperature the Gibbs free energies of 3D and 2D perovskites are very close, suggesting that 2D phases can be easily formed at high temperatures. The product of the BaS and ZrS
2 solid-state reaction, in different stoichiometric conditions, presents a mixture of BaZrS
3 and Ba
4Zr
3S
10. To carefully resolve the composition, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis are complemented with Raman spectroscopy. For this purpose, the phonon dispersions, and the consequent Raman spectra, are calculated for the 3D and 2D chalcogenide perovskites, as well as for the binary precursors. This thorough characterization demonstrates the thermodynamic limitations and experimental difficulties in forming phase-pure chalcogenide perovskites through solid-state synthesis and the importance of using multiple techniques to soundly resolve the composition of these materials.
AB - Chalcogenide perovskites have been recently proposed as novel absorber materials for photovoltaic applications. BaZrS
3, the most investigated compound of this family, shows a high absorption coefficient, a bandgap of around 1.8 eV, and excellent stability. In addition to the 3D perovskite BaZrS
3, the Ba–Zr–S compositional space contains various 2D Ruddlesden–Popper phases Ba
n + 1Zr
nS
3n + 1 (with n = 1, 2, 3) which have recently been reported. Herein, it is shown that at high temperature the Gibbs free energies of 3D and 2D perovskites are very close, suggesting that 2D phases can be easily formed at high temperatures. The product of the BaS and ZrS
2 solid-state reaction, in different stoichiometric conditions, presents a mixture of BaZrS
3 and Ba
4Zr
3S
10. To carefully resolve the composition, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis are complemented with Raman spectroscopy. For this purpose, the phonon dispersions, and the consequent Raman spectra, are calculated for the 3D and 2D chalcogenide perovskites, as well as for the binary precursors. This thorough characterization demonstrates the thermodynamic limitations and experimental difficulties in forming phase-pure chalcogenide perovskites through solid-state synthesis and the importance of using multiple techniques to soundly resolve the composition of these materials.
KW - Ba Zr S
KW - BaZrS
KW - Raman spectroscopy
KW - Ruddlesden–Popper
KW - chalcogenide perovskites
KW - high-temperature syntheses
KW - thermodynamic equilibria
UR - http://www.scopus.com/inward/record.url?scp=85149013848&partnerID=8YFLogxK
U2 - 10.1002/solr.202201078
DO - 10.1002/solr.202201078
M3 - Article
VL - 7
SP - 1
EP - 8
JO - Solar RRL
JF - Solar RRL
IS - 9
M1 - 2201078
ER -