Ternary
metal halides are important photoelectric materials with
proven high performance as absorber layers in solar cells. In this
paper, we explore the crystal structures of the low-cost, nontoxic,
earth-abundant absorber CuBiI4 belonging to Bi-based copper
halide (CuBiI). By performing a global search for minimum energy structures
based on the evolutional genetic algorithm, fifteen crystal structures
of CuBiI4 with low energy are predicted. The energetics
and mechanical and dynamical stability of these structures are comprehensively
investigated. The calculation results show that two P1̅(P1̅ – II; P1̅ – III) structures and one P21/m structure are energetically favorable and have good dynamical
and mechanical stability. The simulated X-ray diffraction curves of
the P21/m structure are highly consistent
with the experimental data. Meanwhile, the three CuBiI4 structures all have high photoelectric conversion efficiency (greater
than 17%), indicating their potential as absorption layer materials
for high-performance solar cells.