Developments and applications of the OPTIMADE API for materials discovery, design, and data exchange.

The Open Databases Integration for Materials Design (OPTIMADE) application programming interface (API) empowers users with holistic access to a growing federation of databases, enhancing the accessibility and discoverability of materials and chemical data. Since the first release of the OPTIMADE specification (v1.0), the API has undergone significant development, leading to the v1.

Motif based high-throughput structure prediction of superconducting monolayer titanium boride.

Two-dimensional boron structures, due to their diverse properties, have attracted great attention because of their potential applications in nanoelectronic devices. A series of TiBn (2 ≤ n ≤ 13) monolayers are efficiently constructed through our motif based method and theoretically investigated through high-throughput first-principles calculations. The configurations are generated based on the motifs of boron dimeric/triangular/quadrilateral fragments and multi-coordinate titanium-centered boron molecular wheels.

Atom Classification Model for Total Energy Evaluation of Two-Dimensional Multicomponent Materials.

The tunable properties of materials originate from variety of structures; however, it is still a challenge to give an accurate and fast evaluation of stabilities for screening numerous candidates. Herein, we propose an atom classification model to describe the multicomponent materials based on the structural recognition, in which the atoms are classified to estimate the total energies. Taking two-dimensional planar CB and C(BN) as examples, we have found that the test error of total energies is about 3 meV per atom.

Opening the Band Gap of Graphene via Fluorination for High-Performance Dual-Mode Photodetector Application.

Fluorination is an effective process to open the band gap of graphene (Gr), which is beneficial to the development of optoelectronic devices working in wide wavelength. Herein, we report a dual-mode broadband photodetector (PD) by integrating fluorinated graphene (F-Gr) with silicon (Si). It is found that when working in photoconductive mode, the F-Gr/Si heterojunction exhibited a remarkable photoresponse over a wide spectral region from ultraviolet (UV), visible to near infrared (NIR) light with a high responsivity ( R) of 1.

Coexistence of Strong Second Harmonic Generation Response and Wide Band Gap in AZn Ga S (A=K, Rb, Cs) with 3D Diamond-like Frameworks.

Mid-infrared (MIR, 2-20 μm) second-order nonlinear optical (NLO) materials with outstanding performances are of great importance in laser science and technology. However, the enormous challenge to design and synthesize an excellent MIR NLO material lies in achieving simultaneously a strong second harmonic generation (SHG) response [d >0.6 × AgGaS (AGS)] and wide band gap (E >3.

Two excellent phase-matchable infrared nonlinear optical materials based on 3D diamond-like frameworks: RbGaSnSe and RbInSnSe.

Mid- and far-infrared (MFIR) nonlinear optical (NLO) crystals with excellent performances are critical to laser frequency-conversion technology. However, the current commercial MFIR NLO crystals, including AgGaS (AGS), AgGaSe and ZnGeP, suffer from certain intrinsic drawbacks and cannot achieve a good balance between large second-harmonic generation (SHG) efficiency and high laser-induced damage thresholds (LIDTs). Herein, we report two new phase-matchable MFIR NLO chalcogenides, specifically RbXSnSe (X = Ga, In), which were successfully synthesized by high-temperature solid-state reactions.

BaCuInS: a quaternary semiconductor with a unique 3D copper-rich framework and ultralow thermal conductivity.

A novel quaternary sulfide, BaCuInS (1), has been successfully synthesized via a high-temperature solid-state reaction. It contains CuSS clusters as basic building blocks, which are connected to one another by discrete In ions to generate a 3D copper-rich framework, where the Ba cations reside. Interestingly, such large clusters that are fused by five crystallographically independent Cu sites with three different chemical environments result in the increase of phonon scattering, which is the crucial factor to the exceptionally low lattice thermal conductivity (ca.

Tailored synthesis of nonlinear optical quaternary chalcohalides: BaGeSCl, BaSiSeCl and BaGeSeCl.

Three novel zero-dimensional quaternary chalcohalides, BaGeSCl, BaSiSeCl and BaGeSeCl, which crystallize in the polar noncentrosymmetric space group P6 (no. 173), have been rationally synthesized by a tailored approach on the basis of unique [MQ] (M = Ge, Q = S; M = Ge/Si, Q = Se) units with Ba cations and Cl anions occupying the interspaces. The [MQ] units which consist of three Q-corner-sharing [MQ] tetrahedra, are arranged along the 6 screw axis.

Non-centrosymmetric Selenides AZn In Se (A=Rb, Cs): Synthesis, Characterization and Nonlinear Optical Properties.

Two new non-centrosymmetric polar quaternary selenides, namely, RbZn In Se and CsZn In Se , have been synthesized and structurally characterized. They exhibit a 3D diamond-like framework (DLF) consisting of corner-shared MSe (M=Zn/In) tetrahedra, in which the A ions are located. Both compounds are thermally stable up to 1300 K and exhibit large transmittance in the infrared region (0.

AXXTe (A = Rb, Cs; X = Mn, Zn, Cd; X = Ga, In): quaternary semiconducting tellurides with very low thermal conductivities.

The discovery of novel materials with very low thermal conductivity is paramount to improving the efficiency of thermoelectric devices. Here we present a series of quaternary semiconducting tellurides AXXTe (A = Rb, Cs; X = Mn, Zn, Cd; X = Ga, In) with three-dimensional (3D) diamond-like frameworks (DLFs) and they exhibit a very low thermal conductivity (ca. 0.

Pb5Ga6ZnS15: a noncentrosymmetric framework with chains of T2-supertetrahedra.

A novel noncentrosysmmetric sulfide, Pb5Ga6ZnS15 (1), was synthesized for the first time. Its crystal structure revealed the presence of [GaS2](-)∞ (chain 1, chains of [GaS4](5-) tetrahedra) and [Ga4S9](6-)∞ (chain 2, chains of T2-supertetrahedra) connected by isolated [ZnS4](6-) tetrahedra. Structure correlation with the network constructed solely using chain 1 (Pb4Ga4GeQ12-type) is discussed.

CsBi4Te6: a new facile synthetic method and mid-temperature thermoelectric performance.

CsBi4Te6 is one of the best performing low-temperature thermoelectric (TE) materials. However, it has not received worldwide intensive investigation due to the limitation of synthetic methods. Here we report a new facile approach by not using the reactive Cs metal and the mid-temperature TE properties have been studied for the first time.

Syntheses, structures, physical and electronic properties of quaternary semiconductors: Cs[RE9Cd4Se18] (RE = Tb-Tm).

Five new quaternary rare-earth selenides, Cs[RE9Cd4Se18] (RE = Tb-Tm), which are the first examples with closed cavities in the quaternary A/RE/Cd/Q (A = alkali metal; RE = rare earth metal; Q = chalcogenide) system, have been synthesized by high-temperature solid state reactions with a modified reactive CsCl flux. Single crystal X-ray diffraction analyses show that these isostructural materials adopted a known BaV13O18-structure type in the trigonal space group R3[combining macron] (no. 148) with cell parameters of a = 17.

(Cs6Cl)6Cs3[Ga53Se96]: A Unique Long Period-Stacking Structure of Layers Made from Ga2Se6 Dimers via Cis or Trans Intralayer Linking.

The new compound (Cs6Cl)6Cs3[Ga53Se96] with its own structure type has been discovered by high-temperature solid-state reactions. The compound features a unique long period-stacking structure of layers that are built by the commonly observed dimeric Ga2Se6 unit extending in cis or trans intralayer linking. Single-crystal X-ray diffraction analyses show the trigonal space group R3̅m (No.