Embedding human knowledge in material screening pipeline as filters to identify novel synthesizable inorganic materials.

How might one embed a chemist's knowledge into an automated materials-discovery pipeline? In generative design for inorganic crystalline materials, generating candidate compounds is no longer a bottleneck - there are now synthetic datasets of millions of compounds. However, weeding out unsynthesizable or difficult to synthesize compounds remains an outstanding challenge. Post-generation "filters" have been proposed as a means of embedding human domain knowledge, either in the form of scientific laws or rules of thumb.

Noncollinear Electric Dipoles in a Polar Chiral Phase of CsSnBr Perovskite.

Polar and chiral crystal symmetries confer a variety of potentially useful functionalities upon solids by coupling otherwise noninteracting mechanical, electronic, optical, and magnetic degrees of freedom. We describe two phases of the 3D perovskite, CsSnBr, which emerge below 85 K due to the formation of Sn(II) lone pairs and their interaction with extant octahedral tilts. Phase II (77 K < < 85 K, space group 2/) exhibits ferroaxial order driven by a noncollinear pattern of lone pair-driven distortions within the plane normal to the unique octahedral tilt axis, preserving the inversion symmetry observed at higher temperatures.

Disentangling the effects of structure and lone-pair electrons in the lattice dynamics of halide perovskites.

Halide perovskites show great optoelectronic performance, but their favorable properties are paired with unusually strong anharmonicity. It was proposed that this combination derives from the ns electron configuration of octahedral cations and associated pseudo-Jahn-Teller effect. We show that such cations are not a prerequisite for the strong anharmonicity and low-energy lattice dynamics encountered in these materials.

Highly Concentrated, Zwitterionic Ligand-Capped Mn:CsPb(Br Cl ) Nanocrystals as Bright Scintillators for Fast Neutron Imaging.

Fast neutron imaging is a nondestructive technique for large-scale objects such as nuclear fuel rods. However, present detectors are based on conventional phosphors (typically microcrystalline ZnS:Cu) that have intrinsic drawbacks, including light scattering, γ-ray sensitivity, and afterglow. Fast neutron imaging with colloidal nanocrystals (NCs) was demonstrated to eliminate light scattering.

Luminescent Lead Halide Ionic Liquids for High-Spatial-Resolution Fast Neutron Imaging.

The fast neutron imaging technique with recoil proton detection harbors significant potential for imaging of thick, large-scale objects containing high-Z elements. However, the challenge to find efficient fast neutron scintillators with high spatial resolution is ongoing. The list of requirements for such scintillators is long and demanding: a proton-rich, scattering-free material combining high light yield with the absence of light reabsorption.

Lone-Pair-Induced Structural Ordering in the Mixed-Valent 0D Metal-Halides RbBi Sb Sb Cl (0 ≤ ≤ 7).

Mixed-valent metal-halides containing s lone pairs may exhibit intense visible absorption, while zero-dimensional (0D) s-based metal-chlorides are generally colorless but have demonstrated promising optoelectronic properties suitable for thermometry and radiation detection. Here, we report solvothermally synthesized mixed-valent 0D metal-halides RbBi Sb Sb Cl (0 ≤ ≤ 7). RbSb Sb Cl crystallizes in an orthorhombic space group () with a unique, layered 0D structure driven by the arrangement of the 5s lone pairs of the SbCl octahedra.

Role of the A-Site Cation in Low-Temperature Optical Behaviors of APbBr (A = Cs, CHNH).

APbBr (A = Cs, CHNH) are prototype halide perovskites having bandgaps of 2.30-2.35 eV at room temperature, rendering their apparent color nearly identical (bright orange but opaque).

Demonstration of Energy-Resolved γ-Ray Detection at Room Temperature by the CsPbCl Perovskite Semiconductor.

The detection of γ-rays at room temperature with high-energy resolution using semiconductors is one of the most challenging applications. The presence of even the smallest amount of defects is sufficient to kill the signal generated from γ-rays which makes the availability of semiconductors detectors a rarity. Lead halide perovskite semiconductors exhibit unusually high defect tolerance leading to outstanding and unique optoelectronic properties and are poised to strongly impact applications in photoelectric conversion/detection.

Static Rashba Effect by Surface Reconstruction and Photon Recycling in the Dynamic Indirect Gap of APbBr (A = Cs, CHNH) Single Crystals.

Recently, halide perovskites have gained significant attention from the perspective of efficient spintronics owing to the Rashba effect. This effect occurs as a consequence of strong spin-orbit coupling under a noncentrosymmetric environment, which can be dynamic and/or static. However, there exist intense debates on the origin of broken inversion symmetry since the halide perovskites typically crystallize into a centrosymmetric structure.

Efficient Lone-Pair-Driven Luminescence: Structure-Property Relationships in Emissive 5s Metal Halides.

Low-dimensional metal halides have been the focus of intense investigations in recent years following the success of hybrid lead halide perovskites as optoelectronic materials. In particular, the light emission of low-dimensional halides based on the 5s cations Sn and Sb has found utility in a variety of applications complementary to those of the three-dimensional halide perovskites because of its unusual properties such as broadband character and highly temperature-dependent lifetime. These properties derive from the exceptional chemistry of the 5s lone pair, but the terminology and explanations given for such emission vary widely, hampering efforts to build a cohesive understanding of these materials that would lead to the development of efficient optoelectronic devices.

Fast Neutron Imaging with Semiconductor Nanocrystal Scintillators.

Fast neutrons offer high penetration capabilities for both light and dense materials due to their comparatively low interaction cross sections, making them ideal for the imaging of large-scale objects such as large fossils or as-built plane turbines, for which X-rays or thermal neutrons do not provide sufficient penetration. However, inefficient fast neutron detection limits widespread application of this technique. Traditional phosphors such as ZnS:Cu embedded in plastics are utilized as scintillators in recoil proton detectors for fast neutron imaging.

Bright Blue and Green Luminescence of Sb(III) in Double Perovskite CsMInCl (M = Na, K) Matrices.

The vast structural and compositional space of metal halides has recently become a major research focus for designing inexpensive and versatile light sources; in particular, for applications in displays, solid-state lighting, lasing, etc. Compounds with isolated ns-metal halide centers often exhibit bright broadband emission that stems from self-trapped excitons (STEs). The Sb(III) halides are attractive STE emitters due to their low toxicity and oxidative stability; however, coupling these features with an appropriately robust, fully inorganic material containing Sb in an octahedral halide environment has proven to be a challenge.

The Rb Bi Sb Cl Family: A Fully Inorganic Solid Solution with Room-Temperature Luminescent Members.

Low-dimensional ns -metal halide compounds have received immense attention for applications in solid-state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb or unstable Sn , and a stable inorganic luminescent material has yet to be found. Here, the zero-dimensional Rb Sb Cl phase, comprised of isolated [SbCl ] octahedra and edge-sharing [Sb Cl ] dimers, shows room-temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.

Publisher Correction: Direct thermal neutron detection by the 2D semiconductor LiInPSe.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Direct thermal neutron detection by the 2D semiconductor LiInPSe.

Highly efficient neutron detectors are critical in many sectors, including national security, medicine, crystallography and astronomy. The main neutron detection technologies currently used involve He-gas-filled proportional counters and light scintillators for thermalized neutrons. Semiconductors could provide the next generation of neutron detectors because their advantages could make them competitive with or superior to existing detectors.

High spectral resolution of gamma-rays at room temperature by perovskite CsPbBr single crystals.

Gamma-ray detection and spectroscopy is the quantitative determination of their energy spectra, and is of critical value and critically important in diverse technological and scientific fields. Here we report an improved melt growth method for cesium lead bromide and a special detector design with asymmetrical metal electrode configuration that leads to a high performance at room temperature. As-grown centimeter-sized crystals possess extremely low impurity levels (below 10 p.

CuISe: A Metal-Inorganic Framework Wide-Bandgap Semiconductor for Photon Detection at Room Temperature.

CuISe is a new wide-bandgap semiconductor with high stability and great potential toward hard radiation and photon detection. CuISe crystallizes in the rhombohedral R3̅m space group with a density of d = 5.287 g·cm and a wide bandgap E of 1.