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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]

Modifiable one-dimensional materials are extremely desired in various applications, especially in room-temperature (RT) chemiresistive gas sensing. New one-dimensional (1D) CdS-based metal chalcogenide nanowires with a surface fully covered amino group (denoted as Cd-ATP) were prepared by the coordination self-assembly method. Featuring densely covered organic functional motifs, Cd-ATP is able to selectively recognize H2S through hydrogen bonding interaction between the amino group and H2S. Cd-ATP exhibits high sensitivity, an ultra-low limit-of-detection (116.49 ppt) and fast response/recovery among all reported room temperature H2S sensing non-composite materials. This work provides inspiration for the design and preparation of novel surface fully functionalized 1D materials for various chemical applications. [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]

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 modification of inorganic two-dimensional (2D) materials with organic functional motifs is in high demand for the optimization of their properties, but it is still a daunting challenge. Organic metal chalcogenides (OMCs) are a type of newly emerging 2D materials, with metal chalcogenide layers covalently anchored by long-range ordered organic functional motifs, these materials are extremely desirable but impossible to realize by traditional methods. Both the inorganic layer and organic functional motifs of OMCs are highly designable and thus provide this type of 2D materials with enormous variety in terms of their structure and properties. This Minireview aims to review the latest developments in OMCs and their bulk precursors. Firstly, the structure types of the bulk precursors for OMCs are introduced. Second, the synthesis and applications of OMC 2D materials in photoelectricity, catalysis, sensors, and energy transfer are explored. Finally, the challenges and perspectives for future research on OMCs are discussed., (© 2022 Wiley-VCH GmbH.)

High-quality MOF thin films with high orientation and controlled thickness are extremely desired for applications. However, they have been only successfully fabricated on flat substrates. Those MOF 2D thin films are limited by low exposed area and slow mass transport. To overcome these issues, MOF 3D thin films with good crystallinity, preferred orientation, and precisely controllable thickness in nanoscale were successfully prepared in a controllable layer-by-layer manner on nanowire array substrate for the first time. The as-prepared Cu-HHTP 3D thin film is superior to corresponding 2D thin films and showed one of the highest sensitivity, lowest LOD, and fastest response among all reported chemiresistive NH 3 sensing materials at RT. This work provides a feasible approach to grow preferred-oriented 3D MOF thin film, offering new perspectives for constructing MOF-based heterostructures for advanced applications., (© 2021 Wiley-VCH GmbH.)

Organic-inorganic hybrid superlattices (OIHSLs) hold attractive physical and chemical properties, while the construction of single-crystal covalent OIHSLs has not been achieved. Herein a coordination assembly strategy was proposed to create a single-crystal covalent OIHSL PbBDT (BDT=1,4-benzenedithiolate), where layered [PbS 2 ] sublattice covalently connects with benzene sublattice. The covalent bonding offers better thermo-/chemi-stability, inter-sublattice electron transport, and unique organic-group-functionalized surface, which may enable better performances in chemical applications than non-covalent OIHSL. These features endow PbBDT with the highest sensitivity, the lowest detection limit and excellent selectivity towards NO 2 at room temperature among all chemiresistive gas-sensing materials with reported response time less than 2 min without the need of light assistance., (© 2021 Wiley-VCH GmbH.)