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Luminescent metal-organic frameworks (LMOFs) with diverse structural features and promising fluorescence-based applications have attracted wide attention in the past two decades. In this work, a LMOF with the formula [Ca4(tcbpe-F)2(H2O)3] (1, LMOF-411) has been constructed from calcium (Ca) and 1,1,2,2-tetrakis(4-(4-carboxyphenyl)phenyl)ethene (H4tcbpe-F). Compound 1 features a three-dimensional framework with a 10-nodal net topology. Due to the relatively high hydration energy of Ca2+, compound 1 readily transforms into a new phase formulated as [Ca(H2tcbpe-F)(H2O)2] (1') upon exposure to water. Combining experimental characterization and theoretical calculations, we elucidated the mechanism of H2O-induced phase transition from 1 to 1'. Notably, the water induced phase transformation can be detected visibly from the change in luminescence, which originates from the fluorescent linker. Compound 1 emits green light (λ em = 490 nm) under UV excitation, while compound 1' emits bright yellow light (λ em = 550 nm) under blue excitation (450 nm). Compound 1' represents the first Ca based LMOF yellow phosphor and its luminescence quantum yield reaches 68%. It can be coated directly onto a commercial blue light-emitting-diode (LED) chip to fabricate a white LED (WLED).

Directional defects management in polycrystalline perovskite film with inorganic passivator is highly demanded while yet realized for fabricating efficient and stable perovskite solar cells (PSCs). Here, we develop a directional passivation strategy employing a two‐dimensional (2D) material, Cu‐(4‐mercaptophenol) (Cu‐HBT), as a passivator precursor. Cu‐HBT combines the merits of the targeted modification from organic passivator and excellent stability offered by inorganic passivator. Featuring with dense organic functional motifs on its surfaces, Cu‐HBT has the capability to "find" and fasten to the Pb defect sites in perovskites through coordination interactions during a spin‐coating process. During subsequent annealing treatment, the organic functional motifs cleave from Cu‐HBT and convert in situ into p‐type semiconductors, Cu2S and PbS. The resultant Cu2S and PbS not only serve as stable inorganic passivators on the perovskite surface, significantly enhancing cell stability, but also facilitate efficient charge extraction and transport, resulting in an impressive efficiency of up to 23.5 %. This work contributes a new defect management strategy by directionally yielding the stable inorganic passivators for highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H2O on the EC of MOFs is rarely reported. We explored the effect of H2O on the EC in the MOFs (NH2)2‐MIL‐125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 107 on H2SO4@(NH2)2‐MIL‐125 by H2O was observed. Brønsted acid–base pairs formed with the −NH2 groups, and H2SO4 played an important role in promoting the charge transfer from H2O to the MOF. Based on H2SO4@(NH2)2‐MIL‐125, a high‐performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H2O can remarkably influence the EC of MOFs, but it also revealed that post‐modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high‐performance sensing materials. [ABSTRACT FROM AUTHOR]

Accurate fire warning is very important for people's life and property safety. The most commonly used fire alarm is based on the detection of a single factor of gases, smoke particles, or temperature, which easily causes false alarm due to complex environmental conditions. A facile multi‐factor route for fabricating an accurate analog fire alarm using a Pb5S2I6 nanowire mesh based on its photoelectric and gas‐sensing dual function is presented. The Pb5S2I6 nanowire mesh presents excellent photoelectric detection capabilities and is sensitive to ppm‐level NO2 at room temperature. Under the "two‐step verification" circuit of light and gas factors, the bimodal simulation fire alarm based on this Pb5S2I6 nanowire mesh can resist the interference of complex environmental factors and effectively reduce the false alarm rate. [ABSTRACT FROM AUTHOR]

Organic small molecule semiconductor (OSMS) microporous crystals with strong π–π interactions are rare but have great potential in applications requiring both excellent mass and charge transport. To obtain such a microporous structure, effective molecule design and control over the packing of the OSMS are necessary but still challenging. Herein, we report three meso-tetrakis (4-carboxyphenyl) porphyrin (TCPP) based porous OSMS materials, 1, 2 and 3, whose porosity and π–π interactions among TCPPs were modulated by varying the H-bonding linkage nodes. The relationship among the hydrogen bonding structure, packing mode and sensing performances has been carefully studied. With the largest overlap between porphyrin rings and strongest face-to-face π–π interactions in the prepared compound, 1 showed the best performances. Moreover, it also represents the first RT NO2 chemiresistive sensing material that simultaneously achieved an experimental limit of detection as low as 20 ppb and a time of recovery as short as 0.6 min. This work revealed the key role of H-bonding linkage node in constructing a microporous OSMS and provides a new type of high-performance rt chemiresistive gas sensing material. [ABSTRACT FROM AUTHOR]

Herein, we report two nanocluster-based compounds built on an unprecedented cluster [Ba13Sb36Cl34O54]8−, which represents the first example of a discrete alkaline earth (AE)-containing oxochloride cluster and the largest Sb-based oxohalide cluster to date; the proton-conducting property of the compounds was investigated. [ABSTRACT FROM AUTHOR]

A room-temperature solution phase reaction was developed to synthesize a covalent organic framework (COF) for the first time. The synthesized azodioxy-linked porphyrin-based COF (POR-COF) possesses a 2D chess board-like structure in the ab-plane and a 1D channel with an open-window size of around 1.9 nm along the c-axis in the modeled crystal structure. The electrical conductivity of POR-COF increases by more than 3 orders of magnitude through I2 doping. The photoconductivity of the I2-doped COF material was also studied firstly. POR-COF shows interesting doping-enhanced photo-current generation. [ABSTRACT FROM AUTHOR]

Directional defects management in polycrystalline perovskite film with inorganic passivator is highly demanded while yet realized for fabricating efficient and stable perovskite solar cells (PSCs). Here, we develop a directional passivation strategy employing a two-dimensional (2D) material, Cu-(4-mercaptophenol) (Cu-HBT), as a passivator precursor. Cu-HBT combines the merits of the targeted modification from organic passivator and excellent stability offered by inorganic passivator. Featuring with dense organic functional motifs on its surfaces, Cu-HBT has the capability to "find" and fasten to the Pb defect sites in perovskites through coordination interactions during a spin-coating process. During subsequent annealing treatment, the organic functional motifs cleave from Cu-HBT and convert in situ into p-type semiconductors, Cu 2 S and PbS. The resultant Cu 2 S and PbS not only serve as stable inorganic passivators on the perovskite surface, significantly enhancing cell stability, but also facilitate efficient charge extraction and transport, resulting in an impressive efficiency of up to 23.5 %. This work contributes a new defect management strategy by directionally yielding the stable inorganic passivators for highly efficient and stable PSCs., (© 2023 Wiley-VCH GmbH.)

The electronic conductivity (EC) of metal-organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H 2 O on the EC of MOFs is rarely reported. We explored the effect of H 2 O on the EC in the MOFs (NH 2 ) 2 -MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 10 7 on H 2 SO 4 @(NH 2 ) 2 -MIL-125 by H 2 O was observed. Brønsted acid-base pairs formed with the -NH 2 groups, and H 2 SO 4 played an important role in promoting the charge transfer from H 2 O to the MOF. Based on H 2 SO 4 @(NH 2 ) 2 -MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H 2 O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials., (© 2023 Wiley-VCH GmbH.)

Surface modification is a promising method to change the surface properties of nanomaterials, but it is limited in enhancing their intrinsic redox nature. In this work, a "filter amplifier" strategy is proposed for the first time to reverse the intrinsic redox nature of materials. This is demonstrated by coating a COF-316 layer with controlled thickness on TiO 2 to form core-sheath nanowire arrays. This unique structure forms a Z-scheme heterojunction to function as "a filter amplifier" which can conceal the intrinsic oxidative sites and increase the extrinsic reductive sites. Consequently, the selective response of TiO 2 is dramatically reversed from reductive ethanol and methanol to oxidative NO 2 . Moreover, TiO 2 @COF-316 provides remarkably improved sensitivity, response, and recovery speed, as well as unusual anti-humidity properties as compared with TiO 2 . This work not only provides a new strategy to rationally modulate the surface chemistry properties of nanomaterials but also opens an avenue to design high-performance electronic devices with a Z-scheme heterojunction.

The layer-by-layer liquid-phase epitaxy (LBL-LPE) method is widely used in preparing metal-organic framework (MOF) thin films with the merits of controlling thickness and out-of-plane orientation for superior performances in applications. The LBL-LPE growth mechanism related to the grain boundary, structure defect, and orientation is critical but very challenging to study. In this work, a novel "in-plane self-limiting and self-repairing" thin-film growth mechanism is demonstrated by the combination study of the grain boundary, structure defect, and orientation of Cu 3 (HHTP) 2 -xC thin film via microscopic analysis techniques and electrical measurements. This mechanism results a desired high-quality MOF thin film with preferred in-plane orientations at its bottom for the first time and is very helpful for optimizing the LBL-LPE method, understanding the growth cycle-dependent properties of MOF thin film, and inspiring the investigations of the biomimetic self-repairing materials., (© 2022 Wiley-VCH GmbH.)

Luminescent metal-organic frameworks (LMOFs) with diverse structural features and promising fluorescence-based applications have attracted wide attention in the past two decades. In this work, a LMOF with the formula [Ca 4 (tcbpe-F) 2 (H 2 O) 3 ] (1, LMOF-411) has been constructed from calcium (Ca) and 1,1,2,2-tetrakis(4-(4-carboxyphenyl)phenyl)ethene (H 4 tcbpe-F). Compound 1 features a three-dimensional framework with a 10-nodal net topology. Due to the relatively high hydration energy of Ca 2+ , compound 1 readily transforms into a new phase formulated as [Ca(H 2 tcbpe-F)(H 2 O) 2 ] (1') upon exposure to water. Combining experimental characterization and theoretical calculations, we elucidated the mechanism of H 2 O-induced phase transition from 1 to 1'. Notably, the water induced phase transformation can be detected visibly from the change in luminescence, which originates from the fluorescent linker. Compound 1 emits green light ( λ em = 490 nm) under UV excitation, while compound 1' emits bright yellow light ( λ em = 550 nm) under blue excitation (450 nm). Compound 1' represents the first Ca based LMOF yellow phosphor and its luminescence quantum yield reaches 68%. It can be coated directly onto a commercial blue light-emitting-diode (LED) chip to fabricate a white LED (WLED)., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The construction of hydrophobic nanochannel with hydrophilic sites for bionic devices to proximally mimick real bio-system is still challenging. Taking the advantages of MOF chemistry, a highly oriented CuTCPP thin film has been successfully reconstructed with ultra-thin nanosheets to produce abundant two-dimensional interstitial hydrophobic nanochannels with hydrophilic sites. Different from the classical active-layer material with proton transport in bulk, CuTCPP thin film represents a new type of active-layer with proton transport in nanochannel for bionic proton field-effect transistor (H + -FETs). The resultant device can reversibly modulate the proton transport by varying the voltage on its gate electrode. Meanwhile, it shows the highest proton mobility of ≈9.5×10 -3  cm 2  V -1  s -1 and highest on-off ratio of 4.1 among all of the reported H + -FETs. Our result demonstrates a powerful material design strategy for proximally mimicking the structure and properties of bio-systems and constructing bionic electrical devices., (© 2021 Wiley-VCH GmbH.)