Discoveries of novel functional materials have played very important roles to the development of science and technologies and thus to benefit our daily life. Among the diverse materials, metal-organic framework (MOF) materials are rapidly emerging as a unique type of porous and organic/inorganic hybrid materials which can be simply self-assembled from their corresponding inorganic metal ions/clusters with organic linkers, and can be straightforwardly characterized by various analytical methods. In terms of porosity, they are superior to other well-known porous materials such as zeolites and carbon materials; exhibiting extremely high porosity with surface area up to 7000 m(2)/g, tunable pore sizes, and metrics through the interplay of both organic and inorganic components with the pore sizes ranging from 3 to 100 Å, and lowest framework density down to 0.13 g/cm(3). Such unique features have enabled metal-organic frameworks to exhibit great potentials for a broad range of applications in gas storage, gas separations, enantioselective separations, heterogeneous catalysis, chemical sensing and drug delivery. On the other hand, metal-organic frameworks can be also considered as organic/inorganic self-assembled hybrid materials, we can take advantages of the physical and chemical properties of both organic and inorganic components to develop their functional optical, photonic, and magnetic materials. Furthermore, the pores within MOFs can also be utilized to encapsulate a large number of different species of diverse functions, so a variety of functional MOF/composite materials can be readily synthesized. In this Account, we describe our recent research progress on pore and function engineering to develop functional MOF materials. We have been able to tune and optimize pore spaces, immobilize specific functional groups, and introduce chiral pore environments to target MOF materials for methane storage, light hydrocarbon separations, enantioselective recognitions, carbon dioxide capture, and separations. The intrinsic optical and photonic properties of metal ions and organic ligands, and guest molecules and/or ions can be collaboratively assembled and/or encapsulated into their frameworks, so we have realized a series of novel MOF materials as ratiometric luminescent thermometers, O2 sensors, white-light-emitting materials, nonlinear optical materials, two-photon pumped lasing materials, and two-photon responsive materials for 3D patterning and data storage. Thanks to the interplay of the dual functionalities of metal-organic frameworks (the inherent porosity, and the intrinsic physical and chemical properties of inorganic and organic building blocks and encapsulated guest species), our research efforts have led to the development of functional MOF materials beyond our initial imaginations.

Metal-organic frameworks (MOFs) have emerged as particularly exciting inorganic-organic hybrid porous materials which can be simply self-assembled from their corresponding inorganic metal ions/clusters with organic linkers. MOFs can combine the inherent physical and chemical properties of both inorganic and organic photonic units due to their inorganic-organic hybrid nature. Furthermore, the pores within MOFs can also be utilized to encapsulate a large number of guest species as photonic units. The vast combination possibilities, synergistic effects, as well as controllable and ordered arrangements of multiple photonic units (MPUs) have distinguished MOFs from other inorganic and organic photonic materials and enabled them to be a promising platform to realize novel photonic functional applications. In this review, we summarize the recent and important progress in the design and construction of photonic MOFs, as well as their various applications in luminescence sensing, white-light emission, photocatalysis, nonlinear optics, lasing devices, data storage, and biomedicine. In addition, we highlight the construction strategy and the synergistic effects of MOFs towards achieving high performance and novel photonic functions. Finally, we also outline the challenges in these fields and put forward the prospects and directions for future development.

The genetic mechanisms mediating the adaptation of Mycobacterium tuberculosis within the host are poorly understood. The best-characterized regulatory systems in this organism include sigma factors and twocomponent signal transduction systems. mprAB is a two-component system required by M. tuberculosis for growth in vivo during the persistent stage of infection. In this report, we demonstrate that MprAB is stress responsive and regulates the expression of numerous stress-responsive genes in M. tuberculosis. With DNA microarrays and quantitative real-time reverse transcription-PCR, genes regulated by MprA in M. tuberculosis that included two stress-responsive sigma factors were identified. Response regulator MprA bound to conserved motifs in the upstream regions of both sigB and sigE in vitro and regulated the in vivo expression of sigB and sigE in M. tuberculosis. In addition, mprA itself was induced following exposure to stress, establishing a direct role for this regulatory system in stress response pathways of M. tuberculosis. Induction of mprA and sigE by MprA in response to stress was mediated through the cognate sensor kinase MprB and required expression of the extracytoplasmic loop domain. These results provide the first evidence that recognition of and adaptation to specific stress in M. tuberculosis are mediated through activation of a two-component signal transduction system that directly regulates the expression of stress-responsive determinants.

Metal-halide perovskites represent a class of promising light absorbers for efficient solar cells. [1][2][3][4][5] The propensity of perovskite films for low-cost solution processing also encourages scientists to explore potential applications beyond solar cells. [6][7][8][9] In particular, as emitters, perovskites exhibit intriguing luminescent properties such as narrowband emission, spectral tunability, and high quantum efficiency, which enables applications in the microlasers and light-emitting diodes (LEDs). [10][11][12][13] The luminescence efficiency of perovskites generally relies on nanostructures that can spatially confine excitons, and consequently reduce the possibility of nonradiative recombination during the carrier/ exciton migration. However, nanocrystals, due to boundary scattering of carriers, generally face the problem of poor charge transport, which is undesirable for LED performance. 2D perovskites, where bulky organic layers and inorganic layers are alternately and periodically arranged, feature natural quantum-well structures. This quantum-well structure is regarded as promising LED emitters for decades. [14][15][16] However, low photoluminescence quantum yields (PLQYs, typically < 1%) of 2D perovskites at room temperature is a bottleneck to achieving high-performance LEDs. [17] The low PLQYs may be attributed to insufficient confinement of Wannier type excitons within the inorganic layers [18] as suggested by the long charge-carrier/exciton diffusion length (60 nm). [19] Engineering crystal structures of low-dimensional (0D to 2D) perovskites by employing suitable organic ammonium cations is the predominant methods for the tuning of luminescence, both in spectral coverage and efficiency. [20,21] In these cases, severe structural distortion of metal halide octahedra is a common feature because of the size mismatch between organic and inorganic components, which results in potential fluctuations. [22,23] Such fluctuations of potential within an inorganic layer of perovskite sometimes, but not always, [20,21] slow the diffusion of carriers or excitons, and consequently induce self-trapped excitons (STEs), which represents a type of bound states for efficient radiative recombination. However, the occurrence of exciton self-trapping in semiconductors is the exception rather than the rule. [24] In parallel, compositional engineering As emerging efficient emitters, metal-halide perovskites offer the intriguing potential to the low-cost light emitting devices. However, semiconductors generally suffer from severe luminescence quenching due to insufficient confinement of excitons (bound electron-hole pairs). Here, Sn-triggered extrinsic self-trapping of excitons in bulk 2D perovskite crystal, PEA 2 PbI 4 (PEA = phenylethylammonium), is reported, where exciton self-trapping never occurs in its pure state. By creating local potential wells, isoelectronic Sn dopants initiate the localization of excitons, which would further induce the large lattice deformation around the impurities to accommodate the se...

The first luminescent two-dimensional MOF nanosheets NTU-9-NS Ti2(HDOBDC)2(H2DOBDC) (H2DOBDC=2,5dihydroxyterephthalic acid) fabricated via top-down delamination have been realized for fast-response and highly sensitive sensing of Fe 3+ . The highly dispersive nature and high accessible active sites on the surface of the 2D NTU-9-NS nanosheets enable them to have close contact with targeted metal ions, which led to fast-response and highly sensitive sensing of Fe 3+ ions, with the response time within seconds and the best detection limit performance of 0.45 µM among MOF materials. The fast-response and highly sensitive Fe 3+ sensing based on the NTU-9-NS nanosheets sensor material highlights the very promise of luminescent sensing applications of two-dimensional MOF nanosheet approach. This work contributes to develop the research on two-dimensional MOF nanosheets materials with targeted and specific recognition for the biological and environmental luminescent sensors.

Digital PCR (dPCR) has developed considerably since the publication of the Minimum Information for Publication of Digital PCR Experiments (dMIQE) guidelines in 2013, with advances in instrumentation, software, applications, and our understanding of its technological potential. Yet these developments also have associated challenges; data analysis steps, including threshold setting, can be difficult and preanalytical steps required to purify, concentrate, and modify nucleic acids can lead to measurement error. To assist independent corroboration of conclusions, comprehensive disclosure of all relevant experimental details is required. To support the community and reflect the growing use of dPCR, we present an update to dMIQE, dMIQE2020, including a simplified dMIQE table format to assist researchers in providing key experimental information and understanding of the associated experimental process. Adoption of dMIQE2020 by the scientific community will assist in standardizing experimental protocols, maximize efficient utilization of resources, and further enhance the impact of this powerful technology.

Higher order multiphoton-pumped polarized lasers have fundamental technological importance. Although they can be used to in vivo imaging, their application has yet to be realized. Here we show the first polarized three-photon-pumped (3PP) microcavity laser in a single host–guest composite metal–organic framework (MOF) crystal, via a controllable in situ self-assembly strategy. The highly oriented assembly of dye molecules within the MOF provides an opportunity to achieve 3PP lasing with a low lasing threshold and a very high-quality factor on excitation. Furthermore, the 3PP lasing generated from composite MOF is perfectly polarized. These findings may eventually open up a new route to the exploitation of multiphoton-pumped solid-state laser in single MOF microcrystal (or nanocrystal) for future optoelectronic and biomedical applications.

and then generate a high-energy photon through radiation transitions from the excited state. Compared with single photon excited luminescence, MPE luminescence has the advantages of stronger spatial confinement, longer penetration depth, smaller biological damage, and less Rayleigh scattering, so the high-order MPE luminescence materials have great potential applications in bioimaging, 3D optical data storage, sensing, and so on, but basically have not been fulfilled yet, [1][2][3][4][5] mainly because of the big challenge and difficulty to realize high-order MPE luminescence. Even for those materials exhibiting such MPE luminescence, the five-photon excited luminescence phenomena can be only observed in the dispersed solutions of either organic chromophore molecules or core-shell halide perovskite semiconductor nanocrystals (MAPbBr 3 /(OA) 2 PbBr 4 ) in order to diminish the aggregation-caused quenching (ACQ) while still with quite low multiphoton action cross-sections (MPACs), or have poor stability without any encapsulation approaches (The MPAC (ησ n ) is the product of photoluminescence quantum yield (PLQY, η) and multiphoton absorption cross-section (σ n ), the parameter to evaluate the multiphoton excited luminescence brightness). [6,7] The deficiency of bulky high-order MPE luminescence solid single crystals with low excitation threshold have further limited the exploration and implementation of such MPE materials into miniaturization and device, and thus their practical applications.Some porous materials such as mesoporous silica and porous alumina have been utilized to confine dye molecules and perovskite nanoparticles and thus to diminish the ACQ and to develop the solid-state luminescence. [4,[8][9][10][11] The emergence of a new type of porous materials, metal-organic frameworks (MOFs), has provided the significant promise to provide much better confinement for the potentially luminescent dye molecules and perovskite nanoparticles because of their more tunable pores/cages and specific sites to introduce strong recognitions. Indeed, we have recently realized a three-photon excited emissive material ZJU-68⊃DMASM through an exact match of a dye molecule with the pores of the metal-organic framework although high-order MPE luminescence solid single The development of the photostable higher-order multiphoton-excited (MPE) upconversion single microcrystalline material is fundamentally and technologically important, but very challenging. Here, up to five-photon excited luminescence in a host-guest metal-organic framework (MOF) and perovskite quantum dot (QD) hybrid single crystal ZJU-28⊃MAPbBr 3 is shown via an in situ growth approach. Such a MOF strategy not only results in a high QD loading concentration, but also significantly diminishes the aggregationcaused quenching (ACQ) effect, provides effective surface passivation, and greatly reduces the contact of the QDs with the external bad atmosphere due to the confinement effect and protection of the framework. These advantages make the resulting ZJU-28⊃MAPb...