Chromophore-Based Luminescent Metal–Organic Frameworks as Lighting Phosphors

Energy-efficient solid-state-lighting (SSL) technologies are rapidly developing, but the lack of stable, high-performance rare-earth free phosphors may impede the growth of the SSL market. One possible alternative is organic phosphor materials, but these can suffer from lower quantum yields and thermal instability compared to rare-earth phosphors. However, if luminescent organic chromophores can be built into a rigid metal–organic framework, their quantum yields and thermal stability can be greatly improved. This Forum Article discusses the design of a group of such chromophore-based luminescent metal–organic frameworks with exceptionally high performance and rational control of the important parameters that influence their emission properties, including electronic structures of chromophore, coligands, metal ions, and guest molecules

High-Performance Blue-Excitable Yellow Phosphor Obtained from an Activated Solvochromic Bismuth-Fluorophore Metal–Organic Framework

We report the synthesis, structure, and photoluminescence properties of a new bismuth based luminescent metal–organic framework (LMOF). The framework is comprised of a 9-coordinated Bi³⁺ building unit and 4′, 4‴, 4⁗′, 4⁗‴-(ethene-1,1,2,2-tetrayl)­tetrakis­([1,1′-biphenyl]-4-carboxylic acid) (H₄tcbpe) organic linker, which has strong yellow aggregation induced emission (AIE). The structure can be viewed as two interpenetrated 4,4-anionic nets that are stabilized by K⁺ ions forming one-dimensional helical inorganic chains by connecting bismuth nodes through shared oxygen bonds. The as-made LMOF has a bluish emission centered at 459 nm with an internal quantum yield of 57% when excited at 360 nm. The emission properties of the LMOF were found to be highly solvochromic with respect to DMF. Upon partial solvent removal, the framework undergoes significant red-shifting to a greenish emission centered at 500 nm. Complete removal of DMF results in additional red-shifting fluorescence coupled with structural changes. The resulting material has strong blue-excitable (455 nm) yellow emission centered at 553 nm, with a quantum yield of 74%, which is maintained after heating in air for 5 days at 90 °C. This is the second highest quantum yield value for blue-excited yellow emission among all reported LMOFs

A Family of Highly Efficient CuI-Based Lighting Phosphors Prepared by a Systematic, Bottom-up Synthetic Approach

Copper­(I) iodide (CuI)-based inorganic–organic hybrid materials in the general chemical formula of CuI­(L) are well-known for their structural diversity and strong photoluminescence and are therefore considered promising candidates for a number of optical applications. In this work, we demonstrate a systematic, bottom-up precursor approach to developing a series of CuI­(L) network structures built on CuI rhomboid dimers. These compounds combine strong luminescence due to the CuI inorganic modules and significantly enhanced thermal stability as a result of connecting individual building units into robust, extended networks. Examination of their optical properties reveals that these materials not only exhibit exceptionally high photoluminescence performance (with internal quantum yield up to 95%) but also that their emission energy and color are systematically tunable through modification of the organic component. Results from density functional theory calculations provide convincing correlations between these materials’ crystal structures and chemical compositions and their optophysical properties. The advantages of cost-effective, solution-processable, easily scalable and fully controllable synthesis as well as high quantum efficiency with improved thermal stability, make this phosphor family a promising candidate for alternative, RE-free phosphors in general lighting and illumination. This solution-based precursor approach creates a new blueprint for the rational design and controlled synthesis of inorganic–organic hybrid materials

A Family of Highly Efficient CuI-Based Lighting Phosphors Prepared by a Systematic, Bottom-up Synthetic Approach

Copper­(I) iodide (CuI)-based inorganic–organic hybrid materials in the general chemical formula of CuI­(L) are well-known for their structural diversity and strong photoluminescence and are therefore considered promising candidates for a number of optical applications. In this work, we demonstrate a systematic, bottom-up precursor approach to developing a series of CuI­(L) network structures built on CuI rhomboid dimers. These compounds combine strong luminescence due to the CuI inorganic modules and significantly enhanced thermal stability as a result of connecting individual building units into robust, extended networks. Examination of their optical properties reveals that these materials not only exhibit exceptionally high photoluminescence performance (with internal quantum yield up to 95%) but also that their emission energy and color are systematically tunable through modification of the organic component. Results from density functional theory calculations provide convincing correlations between these materials’ crystal structures and chemical compositions and their optophysical properties. The advantages of cost-effective, solution-processable, easily scalable and fully controllable synthesis as well as high quantum efficiency with improved thermal stability, make this phosphor family a promising candidate for alternative, RE-free phosphors in general lighting and illumination. This solution-based precursor approach creates a new blueprint for the rational design and controlled synthesis of inorganic–organic hybrid materials

A Family of Highly Efficient CuI-Based Lighting Phosphors Prepared by a Systematic, Bottom-up Synthetic Approach

Copper­(I) iodide (CuI)-based inorganic–organic hybrid materials in the general chemical formula of CuI­(L) are well-known for their structural diversity and strong photoluminescence and are therefore considered promising candidates for a number of optical applications. In this work, we demonstrate a systematic, bottom-up precursor approach to developing a series of CuI­(L) network structures built on CuI rhomboid dimers. These compounds combine strong luminescence due to the CuI inorganic modules and significantly enhanced thermal stability as a result of connecting individual building units into robust, extended networks. Examination of their optical properties reveals that these materials not only exhibit exceptionally high photoluminescence performance (with internal quantum yield up to 95%) but also that their emission energy and color are systematically tunable through modification of the organic component. Results from density functional theory calculations provide convincing correlations between these materials’ crystal structures and chemical compositions and their optophysical properties. The advantages of cost-effective, solution-processable, easily scalable and fully controllable synthesis as well as high quantum efficiency with improved thermal stability, make this phosphor family a promising candidate for alternative, RE-free phosphors in general lighting and illumination. This solution-based precursor approach creates a new blueprint for the rational design and controlled synthesis of inorganic–organic hybrid materials

A Family of Highly Efficient CuI-Based Lighting Phosphors Prepared by a Systematic, Bottom-up Synthetic Approach

Copper­(I) iodide (CuI)-based inorganic–organic hybrid materials in the general chemical formula of CuI­(L) are well-known for their structural diversity and strong photoluminescence and are therefore considered promising candidates for a number of optical applications. In this work, we demonstrate a systematic, bottom-up precursor approach to developing a series of CuI­(L) network structures built on CuI rhomboid dimers. These compounds combine strong luminescence due to the CuI inorganic modules and significantly enhanced thermal stability as a result of connecting individual building units into robust, extended networks. Examination of their optical properties reveals that these materials not only exhibit exceptionally high photoluminescence performance (with internal quantum yield up to 95%) but also that their emission energy and color are systematically tunable through modification of the organic component. Results from density functional theory calculations provide convincing correlations between these materials’ crystal structures and chemical compositions and their optophysical properties. The advantages of cost-effective, solution-processable, easily scalable and fully controllable synthesis as well as high quantum efficiency with improved thermal stability, make this phosphor family a promising candidate for alternative, RE-free phosphors in general lighting and illumination. This solution-based precursor approach creates a new blueprint for the rational design and controlled synthesis of inorganic–organic hybrid materials

Effective Detection of Mycotoxins by a Highly Luminescent Metal–Organic Framework

We designed and synthesized a new luminescent metal–organic framework (LMOF). LMOF-241 is highly porous and emits strong blue light with high efficiency. We demonstrate for the first time that very fast and extremely sensitive optical detection can be achieved, making use of the fluorescence quenching of an LMOF material. The compound is responsive to Aflatoxin B₁ at parts per billion level, which makes it the best performing luminescence-based chemical sensor to date. We studied the electronic properties of LMOF-241 and selected mycotoxins, as well as the extent of mycotoxin–LMOF interactions, employing theoretical methods. Possible electron and energy transfer mechanisms are discussed

Highly Luminescent Metal–Organic Frameworks Based on an Aggregation-Induced Emission Ligand as Chemical Sensors for Nitroaromatic Compounds

Three new luminescent metal–organic frameworks (LMOFs) based on d¹⁰ metals (Zn²⁺, Cd²⁺) and the highly emissive aggregation-induced emission ligand 1,1,2,2-tetrakis­(4-(4-carboxyphenyl)­phenyl)­ethene­(H₄tcbpe) are reported, with the formulas [Cd₃(tcbpe)_1.5­(DMF)­(H₂O)₂]­·(DMF)₆­·(C₂H₅OH)₃ (<b>1</b>), [Zn­(tcbpe)­(DMF)]­·(MeCN) (<b>2</b>), and [Cd­(tcbpe)]­·(MeCN) (<b>3</b>). Compounds <b>1</b> and <b>2</b> both emit strong green light with internal quantum yields (IQYs) as high as 66.8% and 65.7%, respectively, while compound <b>3</b> emits bluish green light with 37.2% IQY. A solution-phase sensing study shows that <b>1</b> has the highest sensitivity to nitroaromatic compounds and demonstrates that it is potentially useful as a luminescence-based chemical sensor. Density functional theory calculations are used to explain the sensing mechanism and relative sensitivity of compound <b>1</b> to various nitroaromatic compounds