A new metal complex-templated silver iodobismuthate exhibiting photocurrent response and photocatalytic property

1D Lead Bromide Hybrids Directed by Complex Cations: Syntheses, Structures, Optical and Photocatalytic Properties

This study presents the synthesis, structural characterization, and evaluation of the photocatalytic performance of two novel one-dimensional (1D) lead(II) bromide hybrids, [Co(2,2'-bpy)3][Pb2Br6CH3OH] (1) and [Fe(2,2'-bpy)3][Pb2Br6] (2), synthesized via solvothermal reactions. These compounds incorporate transition metal complex cations as structural directors, contributing to the unique photophysical and photocatalytic properties of the resulting materials. Single-crystal X-ray diffraction analysis reveals that both compounds crystallize in monoclinic space groups with distinct 1D lead bromide chain configurations influenced by the nature of the complex cations. Optical property assessments show band gaps of 3.04 eV and 2.02 eV for compounds 1 and 2, respectively, indicating their potential for visible light absorption. Photocurrent measurements indicate a significantly higher electron-hole separation efficiency in compound 2, correlated with its narrower band gap. Additionally, photocatalytic evaluations demonstrate that while both compounds degrade organic dyes effectively, compound 2 also exhibits notable hydrogen evolution activity under visible light, a property not observed in 1. These findings highlight the role of metal complex cations in tuning the electronic and structural properties of lead(II) bromide hybrids, enhancing their applicability in photocatalytic and optoelectronic devices.

[Ag4Br6] cluster-based 3D bromoargentate hybrid: crystal structure, optical/photoelectrical performance and theoretical study

The self-assembly of cluster-based halide framework materials has been a matter of great interest but with great challenges. Herein, by exploiting hexamethylenetetramine (Hmta) with Td symmetry as a structural modifier, we successfully constructed and systematically characterized an unusual three-dimensional (3D) hybrid bromoargentate, namely K[NH4][Ag4Br6(Hmta)] (1), bearing a diamond-type [Ag4Br6(Hmta)]n2n- anionic skeleton built up from adamantane-like units of inorganic [Ag4Br6] clusters and organic Hmta ligands. UV-Vis diffuse reflectance analysis showed that the optical bandgap of the title compound was 2.68 eV, indicating a visible-light-responsive semiconductive behavior. More importantly, upon alternate light illumination, the so-designed compound exhibited remarkable photoelectric switching properties, with photocurrent densities (0.38 and 1.10 μA cm-2 for visible and full-spectrum light, respectively) that compete well with and even exceed those of some high-performance metal halide counterparts. Further theoretical calculations, including band structure, density of states, and wave functions, revealed that compound 1 has a unique valence band and conduction band distribution, rendering it with small effective masses (especially the electrons), which may be responsible for its good photoelectricity. Furthermore, in this work, Hirshfeld surface analysis, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS) studies were performed.

A New 3D Iodoargentate Hybrid: Structure, Optical/Photoelectric Performance and Theoretical Research

The explorations of new three-dimensional (3D) microporous metal halides, especially the iodoargentate-based hybrids, and understanding of their structure-activity relationships are still quite essential but full of great challenges. Herein, with the aromatic 4,4'-dpa (4,4'-dpa = 4,4'-dipyridylamine) ligands as the structural directing agents, we solvothermal synthesized and structurally characterized a novel member of microporous iodoargentate family, namely [H2-4,4'-dpa]Ag6I8 (1). Compound 1 possesses a unique and complicated 3D [Ag6I8]n2n- anionic architecture that was built up from the unusual hexameric [Ag6I13] secondary building units (SBUs). Research on optical properties indicated that compound 1 exhibited semiconductor behavior, with an optical band gap of 2.50 eV. Under the alternate irradiation of light, prominent photoelectric switching abilities could be achieved by compound [H2-4,4'-dpa]Ag6I8, whose photocurrent densities (0.37 μA·cm-2 for visible light and 1.23 μA·cm-2 for full-spectrum) compared well with or exceeded those of some high-performance halide counterparts. Further theoretical calculations revealed that the relatively dispersed conduction bands (CBs) structures in compound 1 induced higher electron mobilities, which may be responsible for its good photoelectricity. Presented in this work also comprised the analyses of Hirshfeld surface, powder X-ray diffractometer (PXRD), thermogravimetric measurement, energy-dispersive X-ray spectrum (EDX) along with X-ray photoelectron spectroscopy (XPS).

Three Iodoargentate-Based Hybrids Decorated by Metal Complexes: Structures, Optical/Photoelectric Properties and Theoretical Studies

So far, the development of new iodoargentate-based hybrids, especially those compounds with metal complex cations, and the understanding of their structure-activity relationships have been of vital importance but full of challenges. Herein, using the in-situ-generated metal complex cations as structural directing agents, three new iodoargentate-based hybrids, namely, [Co(phen)3]Ag2PbI6 (phen = 1,10-phenanthroline; 1), [Ni(5,5-dmpy)3]Ag7I9·CH3CN (5,5-dmpy = 5,5-dimethyl-2,2-bipyridine; 2) and [Co(5,5-dmpy)3]Ag5I8 (3), have been solvothermally prepared and then structurally characterized. Compound 1 represents one new heterometallic Ag-Pb-I compound characteristic of the chain-like [Ag2PbI6]n2n- anions. Compound 2 features the straight one-dimensional (1D) [Ag7I9]n2n- anionic moieties, while compound 3 contains infrequent two types of curved [Ag5I8]n3n- anions. Optical properties reveal that the title compounds exhibit interesting semiconductor behaviors with the band gaps of 1.59-2.78 eV, which endow them with good photoelectric switching performances under the alternate light irradiations. We also present their Hirshfeld surface analyses, and the theoretical studies (band structures, density of states (DOS) and partial density of states (PDOS)).

Syntheses, structures, photoelectric properties and photocatalysis of iodobismuthate hybrids with lanthanide complex cations

New iodobismuthate hybrids with lanthanide complex counter cations, [Ln(DMF)₈][Bi₂I₉] (Ln = La (1), Eu (2)) and [Tb(DMF)₈]₂[Bi₂I₉]₂ (3) (DMF = N,N-dimethylformamide), were prepared using solvated Ln(III) complexes formed in situ as structure-directing agents. The dimeric [Bi₂I₉]^3- anion moieties of compounds 1-3 are aggregated by two slightly twisted BiI₆ octahedra through face-sharing mode. The different crystal structures of 1-3 are due to the different I⋯I and C-H⋯I hydrogen bond interactions. Compounds 1-3 have narrow semiconducting band gaps at 2.23, 1.91 and 1.94 eV, respectively. Under Xe light irradiation, they exhibit steady photocurrent densities that are 1.81, 2.10 and 2.18 times higher than that of pure BiI₃, respectively. Compounds 2 and 3 exhibited higher catalytic activities than 1 in the photodegradation of organic dyes CV and RhB, which are attributed to the stronger photocurrent response derived from the redox cycles of Eu³⁺/Eu²⁺ and Tb⁴⁺/Tb³⁺.

A semiconductive copper iodobismuthate hybrid: structure, optical properties and photocurrent response

Pursuits of new types of Pb-free heterometallic halides adequate for photovoltaic applications are still urgent but challenging. In this study, by using in situ-produced [(Me)₂-(DABCO)]²⁺ (DABCO = 1,4-diazabicyclo[2.2.2]octane; Me = methyl) cations as structure-directing agents, we successfully constructed a non-perovskite copper iodobismuthate hybrid, namely [(Me)₂-(DABCO)]₂Cu₂Bi₂I₁₂ (1), which features discrete [Cu₂Bi₂I₁₂]^4- anionic moieties formed by the building units of [CuI₄] tetrahedra and [BiI₆] octahedra. UV-Vis diffuse reflectance analyses showed that compound 1 possesses semiconductive behaviors with a narrow optical bandgap of 1.80 eV. More importantly, it exhibits excellent photoelectric switching abilities, and its photocurrent density (2.30 μA cm^-2) far exceeds those of some high-performance halide-based counterparts. Different from many heterometallic analogues, noteworthily, it also has dispersive band structure and strong electronic coupling near the Fermi level, resulting in a material with small effective masses that may be responsible for the good photoelectricity. This study may offer new guidance for the design and synthesis of eco-friendly heterometallic halides with unique structures and desirable properties.