Antimony and bismuth ⟨111⟩ layered perovskites have recently attracted significant attention as possible, nontoxic alternatives to lead halide perovskites. Unlike lead halide perovskites, however, ⟨111⟩ halide perovskites have shown limited ability to tune their optical and electronic properties. Herein, we report on the metal alloying of manganese and copper into the family of materials with formula Cs 4 Mn 1−x Cu x Sb 2 Cl 12 (x = 0−1). By changing the concentration of manganese and copper, we show the ability to modulate the bandgap of this family of compounds over the span of 2 electron volts, from 3.0 to 1.0 eV. Furthermore, we show that in doing so, we can also adjust other relevant properties such as their magnetic behavior and their electronic structure.

Akin to the expansion in compositional diversity that halide double perovskites provided to three-dimensional perovskites, layered double perovskites could further expand the diversity of two-dimensional (2D) perovskites, and therefore, they could also enhance the properties or expand the possible applications of such materials. Despite the great promise of halide 2D double perovskites, up to date, there are only four confirmed members of this family of materials. Herein, we explore 90 hypothetical new members of this family of materials by a combined theoretical, computational, and experimental method. The combination of these tactics allowed us to predict several new materials, out of which we experimentally synthesized and characterized five new layered double perovskites, some of which show promising properties for their use in photovoltaics and optoelectronics. Further, our work highlights the vast diversity of compositions and therefore of applications that double-layered perovskites have yet to offer.

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The theoretical calculation of pKa values for Brønsted acids is a challenging task that involves sophisticated and time-consuming methods. Therefore, heuristic approaches are efficient and appealing methodologies to approximate these values. Herein, we used the maximum surface electrostatic potential (VS,max) on the acidic hydrogen atoms of carboxylic acids to describe the H-bond interaction with water (the same descriptor that is used to characterize σ-bonded complexes) and correlate the results with experimental pKa values to obtain a predictive model for other carboxylic acids. We benchmarked six different methods, all including an implicit solvation model (water): Five density functionals and the Møller–Plesset second order perturbation theory in combination with six different basis sets for a total of thirty-six levels of theory. The ωB97X-D/cc-pVDZ level of theory stood out as the best one for consistently reproducing the reported pKa values, with a predictive power of 98% correlation in a test set of ten other carboxylic acids.

Theoretical approaches to calculate pKa values for Brønsted acids is a challenging task that, most of the time, involves sophisticated and time-consuming methods. Therefore, heuristic approaches are efficient and appealing methodologies to approximate these values. Herein, by considering the electrostatic potential on acidic hydrogen atoms in a similar fashion that a σ–hole is defined, we calculated the maximum surface potential, VS,max, and used it as a descriptor to correlate it with experimental acidity constants. These values were calculated using the CPCM implicit solvent model (water) with six different methods: five density functionals and the Møller–Plesset second order perturbation theory. Six different basis sets were combined with each method in order to benchmark a total of thirty-six levels of theory. Overall, 1080 calculations were performed and found to correlate with experimental data. The ωB97X-D/6-31+G(d,p) level of theory stands as the best one for consistently reproduce the reported pKa values.