Rb2CuSb7S12: Quaternary Antimony-Rich Semiconductor Featuring a Three-Dimensional Open Framework and Exhibiting an Intriguing Photocurrent Response

Syntheses, crystal structure, and photoelectric properties of two selenoantimonates A-Zn-Sb-Se (A = Rb and Cs)

Metal chalcogenides, as a new class of semiconductor materials, have a broad range of applications in synthetic chemistry due to their rich structures and excellent properties. We have synthesized two selenoantimonates A4Zn2Sb2Se7 [A = Rb(1), Cs(2)] under solvothermal conditions in the visible region using a band gap optimization strategy with alkali metals as structure-directing agents. Compounds 1 and 2 have a two-dimensional layered structure consisting of charge-balanced Rb+(1) or Cs+(2) cations and [Zn2Sb2Se7]4- anions with novel 20-membered rings (20-MR) [Zn6Sb4Se10] with an aperture of 5.6949 × 13.7741 Å2 formed in the middle. Furthermore, we have investigated the crystal structure, band gap, photoelectronic properties, and energy band structure.

Synthesis, crystal and electronic structures, linear and nonlinear optical properties, and photocurrent response of oxyhalides CeHaVIO4 (Ha = Cl, Br; VI = Mo, W)

Four heteroanionic oxyhalides, CeClMoO4, CeBrMoO4, CeClWO4, and CeBrWO4, have been studied as multifunctional materials, which show a combination of good second harmonic generation (SHG) response and photocurrent signals. Millimeter-sized CeHaVIO4 (Ha = Cl, Br; VI = Mo, W) crystals were grown by halide salt flux. The crystal structure of CeHaVIO4 crystals was accurately determined by single-crystal X-ray diffraction. CeClMoO4, CeBrMoO4, and CeBrWO4 are isostructural to each other, and crystallize in the acentric LaBrMoO4 structure type. CeClWO4 crystallizes in a new structure type with unit cell parameters of a = 19.6059(2) Å, b = 5.89450(10) Å, c = 7.80090(10) Å, and β = 101.4746(8)°. The bandgaps of CeHaVIO4 fall into the range of 2.8(1)-3.1(1) eV, which are much smaller than those of isotypic LaHaVIO4 (Ha = Cl, Br; VI = Mo, W) in the range of 3.9(1)-4.3(1) eV. The narrowing of bandgaps in CeHaVIO4 originates from the presence of partially filled 4f orbitals of cerium atoms, which was confirmed by density functional theory (DFT) calculations. The moderate bandgaps make CeHaVIO4 suitable for infrared nonlinear optical (IR NLO) applications. CeBrMoO4 and CeBrWO4 exhibit moderate SHG responses of 0.58× AGS and 0.46× AGS, respectively, and are both type-I phase-matching materials. Moderate SHG response, easy growth of crystals, high ambient stability, and type-I phase-matching behavior make CeBrMoO4 and CeBrWO4 great materials for IR NLO applications. CeHaVIO4 films also exhibited good photocurrent response upon light radiation. This work demonstrates the rich structural chemistry of the REHaVIO4 (RE = Y, La-Lu; Ha = Cl, Br; VI = Mo, W) family and the potential presence of more multifunctional materials.

Functional Alkali Metal-Based Ternary Chalcogenides: Design, Properties, and Opportunities

The search for novel materials has recently brought research attention to alkali metal-based chalcogenides (ABZ) as a new class of semiconducting inorganic materials. Various theoretical and computational studies have highlighted many compositions of this class as ideal functional materials for application in energy conversion and storage devices. This Perspective discusses the expansive compositional landscape of ABZ compositions that inherently gives a wide spectrum of properties with great potential for application. In the present paper, we examine the technique of synthesizing this particular class of materials and explore their potential for compositional engineering in order to manipulate key functional properties. This study presents the notable findings that have been documented thus far in addition to outlining the potential avenues for implementation and the associated challenges they present. By fulfilling the sustainability requirements of being relativity earth-abundant, environmentally benign, and biocompatible, we anticipate a promising future for alkali metal chalcogenides. Through this Perspective, we aim to inspire continued research on this emerging class of materials, thereby enabling forthcoming breakthroughs in the realms of photovoltaics, thermoelectrics, and energy storage.

Syntheses, crystal structure, and photoelectric properties of two Zn-based chalcogenidoantimonates Zn-Sb-Q (Q = S, Se)

Metal chalcogenides are a special class of semiconducting materials characterized by their rich structures and compositions, making them a promising option for a broad range of applications in the field of inorganic chemistry. However, the path forward is not without its challenges, notably in the realms of interface management and enhancing carrier concentration. To address these issues, we solvothermally synthesized two novel chalcogenidoantimonates [Zn(tren)]2Sb2Se5 (1) [tren = tris (2-aminoethyl) amine] and [Zn(tepa)H]2Sb2S6 (2) (tepa = tetraethylenepentamine) utilizing transition metal Zn by band gap optimization strategy in the visible region. Both compounds exhibited distinct zero-dimensional cluster structures, with transition metal complex cations acting as structure-directing agents. A comprehensive analysis of the electronic structure, band gap, and photocurrent response of these crystals was undertaken, revealing significantly enhanced photocatalytic properties compared to preceding studies. This research underscores the potential of antimony chalcogenides in the realm of photoelectric properties and promotes the applications of chalcogenides.

Ba3HgGa2S7: A Zero-Dimensional Quaternary Sulfide Featuring a Unique [Hg2Ga4S14]12- String and Exhibiting a High Photocurrent Response

The discovery of new types of metal sulfides is attractive because of their rich structures and diverse physical properties. Here, a novel quaternary sulfide, Ba₃HgGa₂S₇ (BHGS), is obtained by a solid-state reaction at 1123 K. It crystallizes in the monoclinic space group P2₁/c, and its zero-dimensional structure features two seesaw-like HgS₂ units and four GaS₄ tetrahedra, constructing a unique [Hg₂Ga₄S₁₄]^12- string. BHGS has a wide band gap of 3.64 eV and a large birefringence of 0.09 at 2100 nm. Specifically, BHGS exhibits a remarkable photocurrent response. This work may be extended to a new family of AE₃M^IIM^III₂Q₇ (AE = Mg, Ca, Sr, Ba; M^II = Zn, Cd, Hg; M^III = Al, Ga, In; Q = S, Se) chalcogenides.

CsCu3SbS4: rational design of a two-dimensional layered material with giant birefringence derived from Cu3SbS4

By introducing Cs into known Cu3SbS4, we successfully obtained a novel thioantimonate, quaternary CsCu3SbS4 with an unprecedented 2D layered structure, which exhibits a giant birefringence (0.232 at 549 nm).

Cs3CuAs4Q8 (Q = S, Se): unique two-dimensional layered inorganic thioarsenates with the lowest Cu-to-As ratio and remarkable photocurrent responses

Inorganic chalcogenides containing cations with lone-pair electrons have attracted considerable attention because of their potential applications in photocatalysis. In this research, two new copper thioarsenates with the lowest Cu-to-As ratio in the quaternary X/Cu/As/Q (X = inorganic cations; Q = chalcogen) system, namely Cs₃CuAs₄Q₈ (Q = S, Se), were obtained by a simple surfactant-thermal method at a low temperature. These two isostructural compounds belong to the monoclinic space group C2/c (no. 15) and are composed charge-balanced Cs⁺ cations and two-dimensional anionic [CuAs₄Q₈]^3- layers. Notably, photo-electrochemical measurements indicate that Cs₃CuAs₄Q₈ possesses a remarkable photocurrent response under simulated solar-light illumination. Further theoretical studies were performed to gain insights into the relationships between electronic structure and optical properties.

Revisiting thiophosphate Pb3P2S8: a multifunctional material combining a nonlinear optical response and photocurrent response

Pb₃P₂S₈ was structurally characterized three decades ago with a second harmonic generation response. In this work, Pb₃P₂S₈ was revisited to investigate its electronic structure via DFT calculations and optical properties by UV-vis measurements, second harmonic generation tests, laser damage threshold tests, and photocurrent measurements. Pb₃P₂S₈ is constructed by [PbS₇] polyhedra and [PS₄] tetrahedra, which was supported by crystal orbital Hamilton population (COHP) calculations. The electron localization function (ELF) simulations revealed the dominantly covalent and ionic bonding nature of P-S interactions and Pb-S interactions, respectively, both of which are strongly polarized. Pb₃P₂S₈ is an indirect n-type semiconductor of 1.8 eV and 2.4(1) eV, which are obtained from DFT calculations and UV-vis measurements, respectively. Pb₃P₂S₈ is a non-type-I phase matching material with a good balance of second harmonic generation (SHG) and laser damage threshold (LDT) of 3.5 × AGS and 2.6 × AGS, respectively (SHG based on 38-50 μm particle size sample). Pb₃P₂S₈ exhibits an intriguing photocurrent response of 45 μA cm^-2 under light irradiation. Pb₃P₂S₈ is a new multifunctional material combining a nonlinear optical response and photocurrent response.

N, Baiyin M. Synthesis, crystal structure, photocatalysis, photocurrent response: one-dimensional K2HgSnSe4 and three-dimensional Na6Cu8Sn3Se13

Two novel selenidostannates were solvothermally synthesized and compound 2 displays a unique 3-D open frame structure.