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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]

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 NH3 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. [ABSTRACT FROM AUTHOR]

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 [PbS2] 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 NO2 at room temperature among all chemiresistive gas‐sensing materials with reported response time less than 2 min without the need of light assistance. [ABSTRACT FROM AUTHOR]

In this paper, two new 1-dimensional edge-shared organic–inorganic metal halide hybrids are reported. The sensitivity to nitrogen dioxide of [(Et) 2 MP]PbBr 3 is dramatically enhanced when the bromine is converted to iodine. [Display omitted] • Two new one-dimensional organic–inorganic metal halide hybrids were synthesized. • The compounds with excellent water stability and semiconducting properties. • A strategy of halogen modulation achieves a dramatic increase in NO 2 sensitivity. Organic-inorganic metal halide hybrids show great potential for applications in catalysis, solar cells, gas sensing, etc. Due to the highly designable structure, a novel strategy could be developed to improve their gas sensitivity in gas detection. Two new organic–inorganic metal halide hybrids have been synthesized using [(Et) 2 MP]+ (MP = p -mercaptopyridine, Et = ethyl) as the cationic template. The 1-dimensional inorganic chain provides good electron transport channels, and the electronic structure can be easily adjusted by changing the halogen to enhance the sensitivity of gas sensing. The difference in response values for NO 2 can reach 27 times before and after the halogen change. This work provides insight into the design of gas-sensing materials with improved properties. [ABSTRACT FROM AUTHOR]