High-throughput screening of perovskite inspired bismuth halide materials: toward lead-free photovoltaic cells and light-emitting diodes.

Toxicity is the main bottleneck for the commercialization of Pb halide perovskites. Bi has been considered a promising metal cation to replace Pb because of its comparable electronic structures with Pb and better stability. Although experimental and theoretical studies have proposed various Bi-based halides, the present achievements in photovoltaic cells and other photoelectronic device fields do not compete with Pb analogs. Thermodynamic stability, bandgap control, and enhancement of carrier transport are fundamental challenges in the context of intrinsic material properties for developing highly efficient Bi-based devices. This study evaluates the potential of Bi-based halide compounds with good stability and electronic properties through high-throughput density functional theory calculations. Lattice structures and compositions are selected based on previous reports and an open material database. Then, we expanded our dataset to cover all possible compositional variations of A- and X-sites and alloying to B-sites. We examined over six-hundred candidates and found ten new candidates that have not been reported previously. Rb3SbBiI9exhibits the best-expected efficiency for high-efficiency solar cells among selected compounds, and other compounds can be used as visible-light-generation sources. Analysis of the screening procedure revealed that vacancy-ordered (A3B2X9)-type Bi-halides exhibit significantly favorable characteristics when compared with those of double perovskites and rudorffite-like structures for Bi-based photoelectronic devices.