High-throughput discovery of trigonal ABX₂ chalcogenides with superior photovoltaic performance

Screening of trigonal ABX₂ chalcogenides for photovoltaic applications was performed through high-throughput first-principles calculations. We systematically evaluated their thermodynamic and dynamical stabilities, followed by the analysis of their optoelectronic properties, such as band gaps, bonding characteristics, exciton behaviors, and absorption capabilities. Five candidates, CsBiS₂, RbBiSe₂, CsBiSe₂, NaBiSe₂, and KBiSe₂, exhibit suitable band gaps (1.1-1.4 eV), high absorption efficiencies (>10⁵ cm^-1), and small exciton binding energies (10-33 meV) for solar cell applications. Their photovoltaic performances were evaluated using the spectroscopic limited maximum efficiency method, which revealed high power conversion efficiencies in range of 31.66% to 32.78%, suggesting their promising potential for solar cell applications.