The ternary V-VI-VII chalcohalides consist of one cation and two anions. Trivalent antimony - with a distinctive 5s2 electronic configuration - can be combined with a chalcogen (e.g., S or Se) and halide (e.g., Br or I) to produce photoactive ferroelectric semiconductors with similarities to the Pb halide perovskites. We report - from relativistic quasi-particle self-consistent GW theory - that these materials have a multi-valley electronic structure with several electron and hole basins close to the band extrema. We predict ionisation potentials of 5.3-5.8 eV from first-principles for the three materials, and assess electrical contacts that will be suitable for achieving photovoltaic action from these unconventional compounds.
Bibliographical noteFunding Information:
We thank J. M. Frost for useful discussions, and acknowledge membership of the UKs HPC Materials Chemistry Consortium, which is funded by EPSRC Grant No. EP/L000202. The work has also been supported by EPSRC through Grant Nos. EP/M009580/1, EP/J017361/1, EP/ M009602/1, and EP/M011631/1. This work benefited from membership of the UK Materials Design Network. Data access statement: The crystal structures reported in this work are available in an on-line repository https://github.com/WMDgroup/ Crystal- structures and the MacroDensity code is freely available from https://github.com/WMD-group/ MacroDensity.
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)