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[Display omitted] Metal-halide perovskites, particularly inorganic cesium-lead halide perovskites, have emerged as exceptional candidates for several technological applications in the 21st century, such as photovoltaic devices, optoelectronic and photocatalysis. This study systematically investigates the CsPbI 3 surfaces through density functional theory (DFT) simulations and morphological analyses. The (0 0 1), (1 1 0), and (1 1 1) surfaces were investigated in terms of their possible terminations (here named α , β , γ , δ and ε), where the relations between their outermost coordination polyhedra, bond lengths, charge distribution, electronic and morphological properties were revealed. The results demonstrate that the (0 0 1) and (1 1 0) surfaces stand out as the most stables, with E s u r f 001 - α = E s u r f 110 - γ = 0.08 J / m 2. Concerning the electronic properties, it is observed that the (1 1 0) and (1 1 1) present α terminations with acceptor states, while the β with donor states, making it possible to tune the system semiconducting behavior (n or p-type) via surface termination control. The Wulff construction was employed to show that (0 0 1), (1 1 0) and (1 1 1) surface stabilizations can produce cubic, dodecahedral and octahedral nanocrystal morphologies, respectively. By probing the depths of CsPbI 3 surfaces, this research advances new concepts about the design and functionalization of perovskite halide, offering a crucial direction for experimental synthesis strategies. [ABSTRACT FROM AUTHOR]

Computational simulations play a significant role in material science, determining material properties, developing new materials, and unveiling their technological applications, including studying halide perovskites. This family of compounds is considered promising for use in photovoltaic cells and light-emitting devices. Understanding surface-dependent properties at the nanoscale is crucial because they can differ significantly from those observed on the macroscale. Taking into this account, the present study utilized DFT/HSE06 approach to elaborate a computational model of CsPbX 3 (X = F, Cl, Br, and I) compounds and their (001) surfaces. This research found that anion X− hardness strongly influences surface stability, cluster distortions, band gap energy, and carrier mobility. PbX 2 surface termination is most stable when X = F, while CsX termination is most stable when X = Cl, Br, and I. According to the anion hardness decrease, outermost clusters in CsX terminations become distorted, and an inverse behavior is observed for PbX 2 terminations. The CsPbX3 (001) surfaces exhibit a direct band gap at the R point, characterized by a significant concentration of electronic states below the Fermi level. Furthermore, it has been observed that the anion hardness is crucial to the availability of bands near the band gap, with a decrease in hardness increasing in available electronic states. The band gap energy (E g a p ) of PbX 2 is slightly larger than that of CsX terminations. In the outermost layers for CsX terminations, significantly larger areas of negative potential occur than the PbX 2. These results provide valuable insights into designing and optimizing nanoscale halide perovskites for various applications. [Display omitted] • Computational simulations shed light on how anion hardness influences the CsPbX3 halide perovskite properties. • Surface-dependent properties are crucial in designing advanced materials for photovoltaic cells and light-emitting devices. • Study reveals PbX 2 surface termination most stable when X = F and CsX termination most stable when X = Cl, Br, and I. • DFT insights into the halide perovskites can facilitate the development of materials with enhanced optoelectronic properties. • Anion hardness have a significant impact on surface cluster, band gap energy, and carrier mobility of CsPbX3 compounds. [ABSTRACT FROM AUTHOR]

The nanoparticle morphology can significantly affect its physical, chemical, and optical properties. In the scheelite group, strontium molybdate (SMO) is an inorganic material widely investigated due to thermal and chemical stability under higher pressure, and their synthesis has been reported via different routes. This work reported a detailed description of the bulk and (001), (100), (101), (103), (111), (112) and (211) surfaces of SMO and a general mapping of morphological transformations, which can be applied to any material that exhibits the scheelite symmetry. The stability order observed for SMO surfaces was: (001) > (112) > (101) > (110) > (111) = (103) > (211) > (100). Surfaces with the same coordination for outermost Sr-centered polyhedra, the higher distortion, the most unstable. In general, it was observed that the most stable surfaces have a higher E g a p compared to the unstable. The highest E g a p is associated with (101) surface (4.48 eV), while the lowest is with (100) (3.25 eV). Disk-like morphologies are associated with (001) surface stabilization, while (112), (101), (111), (103), and (221) minimizations favor the generation of octahedral morphologies, and finally, (110) and (100) surfaces growth induces rod-like morphologies. The relationship between the morphology and surface-dependent properties can be useful for obtaining multifunctional SMO-related systems and optimizing its application in several areas, such as catalysis, photocatalysis, electronics and optics. • Nanoparticle morphology can significantly affect its properties. • SrMoO 4 surfaces have different outermost polyhedra coordination and distortion degrees. • Wulff/Gibbs framework was used to obtain a general morphological mapping of SrMoO 4. • Stability order for SrMoO 4 surfaces: (001)>(112)>(101)>(110)>(111)>(103)>(211)>(100). • SrMoO 4 have band alignment favorable for oxidation and reduction processes. [ABSTRACT FROM AUTHOR]