Functional porous metal–organic frameworks (MOFs) have been explored for a number of potential applications in catalysis, chemical sensing, water capture, gas storage, and separation. MOFs are among the most promising candidates to address challenges facing our society related to energy and environment, but the successful implementation of functional porous MOF materials are contingent on their stability; therefore, the rational design of stable MOFs plays an important role towards the development of functional porous MOFs. In this Focus article, we summarize progress in the rational design and synthesis of stable MOFs with controllable pores and functionalities. The implementation of reticular chemistry allows for the rational top-down design of stable porous MOFs with targeted topological networks and pore structures from the pre-selected building blocks. We highlight the reticular synthesis and applications of stable MOFs: (1) MOFs based on high valent metal ions ( e.g. , Al 3+ , Cr 3+ , Fe 3+ , Ti 4+ and Zr 4+ ) and carboxylate ligands; (2) MOFs based on low valent metal ions ( e.g. , Ni 2+ , Cu 2+ , and Zn 2+ ) and azolate linkers. We envision that the synthetic strategies, including modulated synthesis and post-synthetic modification, can potentially be extended to other more complex systems like metal-phosphonate framework materials.
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The role of photoinduced charge transfer for photocatalysis, photoelectrocatalysis and luminescence sensing in metal–organic frameworks
Metal–organic frameworks (MOFs) have emerged as promising porous optoelectronic compositions for energy conversion and sensing applications. The enormous structural possibilities, the large variety of photo- and redox-active building blocks along with several post-synthetic functionalization strategies make MOFs an ideal platform for photochemical and photoelectrochemical developments. Because MOFs assemble all the active building units in a dense fashion, the non-aggregated yet proximally positioned species ensure efficient photon absorption to drive photoinduced charge transfer (PCT) reactions for energy conversion and sensing. Hence, understanding the PCT processes within MOFs as a function of the topological and electronic structures of the donor–acceptor (D–A) moieties can provide transformative strategies to design new low-density compositions.
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- Award ID(s):
- 1944903
- NSF-PAR ID:
- 10253729
- Date Published:
- Journal Name:
- Dalton Transactions
- Volume:
- 49
- Issue:
- 37
- ISSN:
- 1477-9226
- Page Range / eLocation ID:
- 12892 to 12917
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract The ever‐increasing demand for clean sustainable energy has driven tremendous worldwide investment in the design and exploration of new active materials for energy conversion and energy‐storage devices. Tailoring the surfaces of and interfaces between different materials is one of the surest and best studied paths to enable high‐energy‐density batteries and high‐efficiency solar cells. Metal‐halide perovskite solar cells (PSCs) are one of the most promising photovoltaic materials due to their unprecedented development, with their record power conversion efficiency (PCE) rocketing beyond 25% in less than 10 years. Such progress is achieved largely through the control of crystallinity and surface/interface defects. Rechargeable batteries (RBs) reversibly convert electrical and chemical potential energy through redox reactions at the interfaces between the electrodes and electrolyte. The (electro)chemical and optoelectronic compatibility between active components are essential design considerations to optimize power conversion and energy storage performance. A focused discussion and critical analysis on the formation and functions of the interfaces and interphases of the active materials in these devices is provided, and prospective strategies used to overcome current challenges are described. These strategies revolve around manipulating the chemical compositions, defects, stability, and passivation of the various interfaces of RBs and PSCs.
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Abstract High quantum yield triplets, populated by initially prepared excited singlets, are desired for various energy conversion schemes in solid working compositions like porous MOFs. However, a large disparity in the distribution of the excitonic center of mass, singlet‐triplet intersystem crossing (ISC) in such assemblies is inhibited, so much so that a carboxy‐coordinated zirconium heavy metal ion cannot effectively facilitate the ISC through spin‐orbit coupling. Circumventing this sluggish ISC, singlet fission (SF) is explored as a viable route to generating triplets in solution‐stable MOFs. Efficient SF is achieved through a high degree of interchromophoric coupling that facilitates electron super‐exchange to generate triplet pairs. Here we show that a predesigned chromophoric linker with extremely poor ISC efficiency (
k ISC) butform triplets in MOF in contrast to the frameworks that are built from linkers with sizable k ISCbut. This work opens a new photophysical and photochemical avenue in MOF chemistry and utility in energy conversion schemes. -
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Abstract High quantum yield triplets, populated by initially prepared excited singlets, are desired for various energy conversion schemes in solid working compositions like porous MOFs. However, a large disparity in the distribution of the excitonic center of mass, singlet‐triplet intersystem crossing (ISC) in such assemblies is inhibited, so much so that a carboxy‐coordinated zirconium heavy metal ion cannot effectively facilitate the ISC through spin‐orbit coupling. Circumventing this sluggish ISC, singlet fission (SF) is explored as a viable route to generating triplets in solution‐stable MOFs. Efficient SF is achieved through a high degree of interchromophoric coupling that facilitates electron super‐exchange to generate triplet pairs. Here we show that a predesigned chromophoric linker with extremely poor ISC efficiency (
k ISC) butform triplets in MOF in contrast to the frameworks that are built from linkers with sizable k ISCbut. This work opens a new photophysical and photochemical avenue in MOF chemistry and utility in energy conversion schemes. -
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d0dt02143a
