A 2D silver-iodide-organic framework with both fluorescent and phosphorescent emissions

Recent advances in the design of afterglow materials: mechanisms, structural regulation strategies and applications

Afterglow materials are attracting widespread attention owing to their distinctive and long-lived optical emission properties which create exciting opportunities in various fields. Recent research has led to the discovery of many new afterglow materials featuring high photoluminescence quantum yields (PLQY) and lifetimes of up to several hours under ambient conditions. Afterglow materials are typically categorized according to their luminescence mechanism, such as long-persistent luminescence (LPL), room temperature phosphorescence (RTP), or thermally activated delayed fluorescence (TADF). Through rational design and novel synthetic strategies to modulate spin-orbit coupling (SOC) and populate triplet exciton states (T1), luminophores with long lifetimes and bright afterglow characteristics can be realized. Initial research towards afterglow materials focused mainly on pure inorganic materials, many of which possessed inherent disadvantages such as metal toxicity or low energy emissions. In recent years, organic-inorganic hybrid afterglow materials (OIHAMs) have been developed with high PLQY and long lifetimes. These hybrid materials exploit the tunable structure and easy processing of organic molecules, as well as enhanced SOC and intersystem crossing (ISC) processes involving heavy atom dopants, to achieve excellent afterglow performance. In this review, we begin by briefly discussing the structure and composition of inorganic and organic-inorganic hybrid afterglow materials, including strategies for regulating their lifetime, PLQY and luminescence wavelength. The specific advantages of organic-inorganic hybrid afterglow materials, including low manufacturing costs, diverse molecular/electronic structures, tunable structures and optical properties, and compatibility with a variety of substrates, are emphasized. Subsequently, we discuss in detail the fundamental mechanisms used by afterglow materials, their classification, design principles, and end applications (including sensing, anticounterfeiting, and photoelectric devices, among others). Finally, existing challenges and promising future directions are discussed, laying a platform for the design of afterglow materials for specific applications.

Two Hybrid Polymeric Iodoargentates Incorporating Aromatic N-Heterocycle Derivatives as Electron Acceptors

Two new hybrid polymeric iodoargentates, [Ag₂I₂(phen)]_n (1; phen = 1,10-phenanthroline) and [AgI(bpt)]_n (2; bpt = 3,5-bis(pyrazinyl)-1,2,4-triazole), were prepared by the hydrothermal methods. 1 displays a new type of taenioid, [Ag₂I₂(phen)]_n, chain incorporating phen molecules, while 2 exhibits a unique 2D hybrid iodoargentate based on a combination of the [AgI]_n layer and bpt molecules as electron acceptors. Such a 2D layer is the first example of an inorganic iodoargentate layer covalently bonding to aromatic N-heterocycle derivatives within the iodoargentates. 1 and 2 exhibit photocurrent response properties.

Tunable Luminescence in Hybrid Cu(I) and Ag(I) Iodides

Hybrid materials are increasingly demonstrating their utility across several optical, electrical, and magnetic applications. Cu(I) halide-based hybrids have attracted attention due to their strong luminescence in the absence of rare-earths. Here, we report three Cu(I) and Ag(I) hybrid iodides with 1,5-naphthyridine and additional triphenylphosphine (Ph₃P) ligands. The compounds are built on (Cu/Ag)-I staircase chains or on a rhomboid Cu₂I₂ dimer and display intense and tunable luminescence. Replacing Cu with Ag, and adding the second kind of organic ligand (Ph₃P) tunes the emission color from red to yellow and results in significantly enhanced quantum yield. Density functional theory-based electronic structure calculations reveal the separate effects of the inorganic module and organic ligand on the electronic structure, confirming that bandgap, optical absorption, and emission properties of these phosphors can be systemically and deliberately tuned by metal substitution and organic ligands cooperation. The emerging understanding of composition-structure-property relations in this family provides powerful design tools toward new compounds for general lighting applications.

Semiconducting crystalline inorganic-organic hybrid metal halide nanochains

One-dimensional (1D) inorganic-organic metal halide hybrids at the molecular level, which can be considered as arrays of nanochains isolated by organic components, have shown remarkable optical and electric properties. This review summarizes their reported structural types and shows how to modify their band gaps and optical and electric properties.

Strongly emissive white-light-emitting silver iodide based inorganic–organic hybrid structures with comparable quantum efficiency to commercial phosphors

A series of one-dimensional silver iodide based inorganic–organic hybrid structures with tunable white light emissions and high quantum efficiency have been synthesized by Cu substitution.

New photoluminescent iodoargentates with bisimidazole derivatives as countercations

In this article, three bisimidazole derivatives (1,4-bis(2-ethylimidazol-1-yl)butane, L1; 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl, L2′; and 1,3-bis(2-ethylimidazol-1-yl)propane, L3) were employed to solvothermally react with AgI in an acidic environment, creating three new 1-D chained iodoargentates [H(L1)][Ag₅I₆]·DMF (DMF = N,N′-dimethylformamide) 1, [L2][Ag₃I₅] (L2²⁺ = 4,4′-di(1H-imidazol-1-ium)-1,1′-biphenyl) 2, and [H₂(L3)][Ag₂I₄] 3. L2²⁺ in 2 originated from the in situ N-alkylation of L2′ with the CH₃OH solvent. X-ray single-crystal diffraction analysis reveals that (i) in 1, Ag⁺ and I⁻ aggregate to form a 1-D tube-like iodoargentate, which exhibits the same topology as the carbon tube; (ii) the chain structure of the iodoargentate in 2 is based on a kind of trinuclear Ag–I cluster, which can be viewed as a segment of the classical cubic M₄I₄ cluster; (iii) the chain structure of the iodoargentate in 3 is simple, which can be described as a linear arrangement of the AgI₄ tetrahedra by sharing edges. The photoluminescence analysis reveals that at 77 K, (i) 1 and 2 emit strong yellow light with ms-grade photoluminescence lifetimes (5.460 ms for 1, 6.931 ms for 2); (ii) 3 possesses photochromic luminescence properties. Upon excitation at 254 nm, it emits blue-green light, whereas upon excitation at 365 nm, it emits yellow light.

Three bisimidazole-based chained iodoargentates were solvothermally synthesized, and their photoluminescent behaviors at different temperatures were investigated. Of those, 3 has been found to possess photochromic luminescence properties.

Two Silver Coordination Network Compounds with Colorful Photoluminescence

The excitation-wavelength-dependent photoluminescence (EWDP) property of flexible organic ligand 1,4-bis(2-methyl-imidazol-1-yl)butane (Bmib) was observed. Herein, Bmib was chosen as a bridge linker to react with AgX (X = Br and I) to synthesize novel coordination network compounds (CNCs) with interesting EWDP properties. As anticipated, under the same hydrothermal synthesis conditions, two new isomorphic CNCs, i.e. [Ag2(Bmib)Br2]∞ (IAM16-1) and [Ag2(Bmib)I2]∞ (IAM16-2), as the first examples of CNCs showing EWDP properties, have been obtained. The EWDP properties may be attributed to the stretch and rotation of the long -(CH2)4- chains of Bmib and the spatial orientation adjustment of the methyl group of each imidazole ring at different excitation wavelengths. It is a great challenge to point out the emission mechanisms of CNCs merely from the experimental results due to their multiple charge transfer routes. To address this issue, we adopt DFT calculations to pursue in-depth investigation of the emission mechanisms for IAM16-1 and IAM16-2, respectively.

Coordination polymers built from 1,4-bis(imidazol-1-ylmethyl)benzene: from crystalline to amorphous

A review of the different crystalline and amorphous coordination polymers (CPs) built from 1,4-bis(imidazol-1-ylmethyl)benzene (bix) is presented, with special emphasis on the large variety of structures reported so far and their potential applications.

A two-dimensional silver–iodide organic network constructed from a unique [Ag6I6] hexagonal prism-based one-dimensional column motif

A novel two-dimensional coordination polymer, poly[[μ2-1,3-bis(2-methyl-1H-imidazol-1-yl)propane]di-μ4-iodido-di-μ3-iodido-silver(I)], [Ag4I4(C11H16N4)]n, (I), has been synthesized by solvothermal reaction of AgNO3, KI and 1,3-bis(2-methyl-1H-imidazol-1-yl)propane (bmimp). In (I), the two unique AgIcations have AgNI3and AgI4four-coordinated tetrahedral geometries. The bmimp ligand has imposed twofold symmetry. The AgIcations and iodide anions form a unique one-dimensional polymeric column motif incorporating [Ag6I6] hexagonal prisms, which are then connected by bmimp ligands to form two-dimensional organic–inorganic layers. The layers are arranged in parallel in anABABfashion and are packed into the resultant three-dimensional supramolecular framework by van der Waals interactions.