Revealing the Potential Crystal Structures of Earth-Abundant Nontoxic Photovoltaic CuBiI₄

Abstract

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.

Silver–Bismuth Halide Double Salts for Lead‐Free Photovoltaics: Insights from Symmetry‐Based Modeling

“…In 2017, Ag/Bi lead‐free materials with the stoichiometric formula Ag a Bi b I x () were shown to be highly stable and were proposed as promising materials for solar cell applications, exhibiting well positioned optical bandgaps in the visible, between 1.4 and 2.0 eV. [ 16 ] These materials are in fact a mixture of the two salts: AgI and BiI 3 , and Turkevych et al [ 17 ] proposed to call these compounds “rudorffites”, after Walter Rüdorff and his pioneer work on NaVO 2 , which forms a similar prototypical crystal lattice. [ 18 ] Members of this class of materials are easily processable and were successfully synthesized by spin coating techniques, [ 19 ] thermal coevaporation, [ 20 ] and through a solution atomization to produce aerosols.…”

“…[14,15] In 2017, Ag/Bi lead-free materials with the stoichiometric formula Ag a Bi b I x (x ¼ a þ 3b) were shown to be highly stable and were proposed as promising materials for solar cell applications, exhibiting well positioned optical bandgaps in the visible, between 1.4 and 2.0 eV. [16] These materials are in fact a mixture of the two salts: AgI and BiI 3 , and Turkevych et al [17] proposed to…”

Progress and applications of (Cu–)Ag–Bi–I semiconductors, and their derivatives, as next-generation lead-free materials for photovoltaics, detectors and memristors

“…These calculations showed that all three CuBiI 4 structures have SLMEs in the range of 17% to 20% under 1 sun illumination. 86 These values fall below those of silicon and other established thin-film solar absorbers, which is partly due to the wide bandgap of the materials (close to 2 eV). 86 On the other hand, these bandgaps are close to the ideal value for IPVs (1.9 eV), and the high absorption coefficients suggest that these materials could have higher SLMEs under indoor light spectra.…”

Rudorffites and Beyond: Perovskite‐Inspired Silver/Copper Pnictohalides for Next‐Generation Environmentally Friendly Photovoltaics and Optoelectronics

“…[ 69 ] At the same time, a recent theoretical study by Wang et al predicted 15 possible low‐energy crystal structures of CuBiI 4 . [ 70 ] Initial screening based on the mechanical and dynamic stability proposed three new structures, P 1̅ − II, P 1̅ − III, and P 2 1 / m , as energetically and optoelectronically most favorable. [ 70 ] Experimental evidence supporting these findings is yet to be obtained.…”

“…[ 70 ] Initial screening based on the mechanical and dynamic stability proposed three new structures, P 1̅ − II, P 1̅ − III, and P 2 1 / m , as energetically and optoelectronically most favorable. [ 70 ] Experimental evidence supporting these findings is yet to be obtained.…”