Solution‐processed colloidal quantum dot (CQD) solar cells harvesting the infrared part of the solar spectrum are especially interesting for future use in semitransparent windows or multilayer solar cells. To improve the device power conversion efficiency (PCE) and stability of the solar cells, surface passivation of the quantum dots is vital in the research of CQD solar cells. Herein, inorganic CsPbI3 perovskite (CsPbI3‐P) coating on PbS CQDs with a low‐temperature, solution‐processed approach is reported. The PbS CQD solar cell with CsPbI3‐P coating gives a high PCE of 10.5% and exhibits remarkable stability both under long‐term constant illumination and storage under ambient conditions. Detailed characterization and analysis reveal improved passivation of the PbS CQDs with the CsPbI3‐P coating, and the results suggest that the lattice coherence between CsPbI3‐P and PbS results in epitaxial induced growth of the CsPbI3‐P coating. The improved passivation significantly diminishes the sub‐bandgap trap‐state assisted recombination, leading to improved charge collection and therefore higher photovoltaic performance. This work therefore provides important insight to improve the CQD passivation by coating with an inorganic perovskite ligand for photovoltaics or other optoelectronic applications.

Resistive random-access memory (RRAM) has evolved as one of the most promising candidates for the next-generation memory, but bistability for information storage, simultaneous implementation of resistive switching and rectification effects, and a better understanding of switching mechanism are still challenging in this field. Herein, we report a RRAM device based on a chiral metal-organic framework (MOF) FJU-23-H2O with switched hydrogen bond pathway within its channels, exhibiting an ultralow set voltage (~0.2 V), a high ON/OFF ratio (~105), and a high rectification ratio (~105). It is not only the first MOF with voltage-gated proton conduction but also the first single material showing both rectifying and resistive switching effects. By single-crystal x-ray diffraction analyses, the mechanism of the resistive switching has been demonstrated.

The interfaces between different materials in the heterojunction colloidal quantum dot (QD) solar cell play an important role for charge carrier separation, recombination and collection.

Although supramolecular isomerism in metal-organic frameworks (MOFs) would offer a favorable platform for in-depth exploring their structure-property relationship, the design and synthesis of the isomers are still rather a challenging aspect of crystal engineering. Here, a pair of supramolecular isomers of Co(II)-based MOFs (FJU-88 and FJU-89) can be directionally fabricated by rational tuning the additives. In spite of the fact that the isomers have the similar Co secondary building units and organic linkers, they adopt distinct networks with acs and snw topologies, respectively, which derive from the conformational flexibility of the organic ligands. It is noteworthy that the porous structure of FJU-88 would be collapsed after removal of the solvent from the pores. But FJU-89a shows permanent porosity accompanied with unusual hierarchical micro- and mesopores and superior gas selective adsorption performance. In addition, FJU-89a can efficiently trap CH from CH/CO and CH/CH mixture gases through fixed-bed dynamic breakthrough experiments.

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The construction of colorimetric sensing materials with high selectivity, low detection limits, and great stability provides a significant way for facile device implementation of an ammonia (NH) sensor. Herein, with excellent alkaline stability and exposed N sites in molecule as well as with naked-eye color switching nature generated from changeable cobalt (Co) valence, a three-dimensional mixed-valence cobalt(II/III) metal-organic framework (FJU-56) with tris-(4-tetrazolyl-phenyl)amine (HL) ligand was synthesized for colorimetric sensing toward ammonia. The activated FJU-56 demonstrates a limit of detection of 1.38 ppm for ammonia sensing, with high selectivity in ammonia and water competitive adsorption, and shows outstanding stability and reversibility in the cyclic test. The NH or water molecules binding to the exposed N sites with the hydrogen-bond are observed by single-crystal X-ray diffraction, determining that the attachment of guest molecules to the FJU-56 framework changes the valence of Co ions with a naked-eye color switching response, which provides an ocular demonstration for ammonia capture and a valuable insight into ammonia sensing.

Virtual offices have been a growing trend in today's work environment and have been used to improve organizational performance for several decades. However, more and more companies also experience the challenges and problems brought by the use of virtual office in current years. One famous example would be the Yahoo's decision to withdraw its work-from-home program. Therefore, the studies about the dark side of virtual office start to attract interests from researchers and practitioners. This paper aims at providing a critical view of the changes in employees' work life due to the shift to virtual office from four perspectives: communication, social relation, achievement recognition and work-life balance. This paper also discusses the impact of such changes on employees' quality of work life in terms of job satisfaction. This paper intends to conceptually extend the understanding of alternative working arrangements by considering the "dark side" of virtual office in employees' work life.

BackgroundAflatoxins (AFs) are highly carcinogenic compounds produced by Aspergillus species in seeds with high lipid and protein contents. It has been known for over 30 years that peptone is not conducive for AF productions, although reasons for this remain unknown.ResultsIn this study, we showed that when Aspergillus flavus was grown in peptone-containing media, higher initial spore densities inhibited AF biosynthesis, but promoted mycelial growth; while in glucose-containing media, more AFs were produced when initial spore densities were increased. This phenomenon was also observed in other AF-producing strains including A. parasiticus and A. nomius. Higher peptone concentrations led to inhibited AF production, even in culture with a low spore density. High peptone concentrations did however promote mycelial growth. Spent medium experiments showed that the inhibited AF production in peptone media was regulated in a cell-autonomous manner. mRNA expression analyses showed that both regulatory and AF biosynthesis genes were repressed in mycelia cultured with high initial spore densities. Metabolomic studies revealed that, in addition to inhibited AF biosynthesis, mycelia grown in peptone media with a high initial spore density showed suppressed fatty acid biosynthesis, reduced tricarboxylic acid (TCA) cycle intermediates, and increased pentose phosphate pathway products. Additions of TCA cycle intermediates had no effect on AF biosynthesis, suggesting the inhibited AF biosynthesis was not caused by depleted TCA cycle intermediates.ConclusionsWe here demonstrate that Aspergillus species grown in media with peptone as the sole carbon source are able to sense their own population densities and peptone concentrations to switch between rapid growth and AF production. This switching ability may offer Aspergillus species a competition advantage in natural ecosystems, producing AFs only when self-population is low and food is scarce.