2D compounds with heterolayered architecture for infrared photodetectors.

Compounds with heterolayered architecture, as a family of two-dimensional (2D) materials, are composed of alternating positive and negative layers. Their physical properties are determined not only by the charged constituents, but also by the interaction between the two layers. This kind of material has been widely used for superconductivity, thermoelectricity, energy storage, etc. In recent years, heterolayered compounds have been found as an encouraging choice for infrared photodetectors with high sensitivity, fast response, and remarkable reliability. In this review, we summarize the research progress of heterolayered materials for infrared photodetectors. A simple development history of the materials with three-dimensional (3D) or 2D structures, which are suitable for infrared photodetectors, is introduced firstly. Then, we compare the differences between van der Waals layered 2D materials and heterolayered 2D cousins and explain the advantages of heterolayered 2D compounds. Finally, we present our perspective on the future direction of heterolayered 2D materials as an emerging class of materials for infrared photodetectors.

Self-triggered carboxymethyl chitosan hydrogel for the convenient sustained release of ClO2 gas with environmental stability and long-term antimicrobial effect.

Challenges associated with the storage and uncontrolled release of ClO2 gas present significant hurdles to its practical application. Herein, a clever strategy for self-triggering the sustained release of chlorine dioxide (ClO2) gas is proposed by crosslinking carboxymethyl chitosan (CMCS) with Zn2+ to construct a novel CMCS-Zn@NaClO2 gel with eco-friendly, environmental stability, and convenient, long term, and efficient antibacterial activity. The precursor (NaClO2) in the CMCS solution was alkaline and triggered by the acidic Zn(NO3)2·6H2O solution to achieve sustained self-triggering ClO2 release. The ClO2 gas self-release could be sustained on demand at different temperatures for at least 20 days due to the environmental structure stability of the gel. The hydrogels showed an increase in pore size after sustained release. Molecular dynamics simulations showed the spontaneous release of ClO2 gas at room temperature and the contraction of the CMCS agglomeration, which were consistent with the macroscopic behaviour. The gel displayed a long-acting and high antibacterial efficacy, resulting in a bacteria-killing rate of over 99.9% (inhibitory concentrations of 2.5 mg mL-1 against E. coli and 0.16 mg mL-1 against S. aureus). The hydrogels could effectively extend the shelf life of fruits and demonstrated an excellent wide range of antibacterial properties. This work provides a new approach to solving the storage difficulty of ClO2 gas and offers a fresh perspective on the design of materials with convenient self-triggering release by a precursor, as well as the relationship between the material microstructure and sustained-release behaviour.

Syntheses, Structures, and Photoluminescence of Copper-Based Halides.

Copper-based halides have been found to be a new family of lead-free materials with high stability and superior optoelectrical properties. In this work, we report the photoluminescence of the known (C8H14N2)CuBr3 and the discovery of three new compounds, (C8H14N2)CuCl3, (C8H14N2)CuCl3·H2O, and (C8H14N2)CuI3, which all exhibit efficient light emissions. All these compounds have monoclinic structures with the same space group (P21/c) and zero-dimensional (0D) structures, which can be viewed as the assembly of promising aromatic molecules and different copper halide tetrahedrons. Upon the irradiation of deep ultraviolet light, (C8H14N2)CuCl3, (C8H14N2)CuBr3,, and (C8H14N2)CuI3 show green emission peaking at ∼520 nm with a photoluminescent quantum yield (PLQY) of 3.38, 35.19, and 17.81%, while (C8H14N2)CuCl3·H2O displays yellow emission centered at ∼532 nm with a PLQY of 2.88%. A white light-emitting diode (WLED) was successfully fabricated by employing (C8H14N2)CuBr3 as a green emitter, demonstrating the potential of copper halides for applications in the green lighting field.

Tunable thermal quenching properties of Na3Sc2(PO4)3:Eu2+ phosphors tailored by phase transformation details.

Luminescence thermal quenching of phosphors is one of the prominent problems in restricting their application in high-power LED devices. In the current work, tunable luminescence thermal quenching behaviors, including abnormal negative thermal quenching and normal thermal quenching, were demonstrated for Na3Sc2(PO4)3:Eu2+ phosphors tailored by phase transformation details. A series of ionic substitution schemes were employed to synthesize α-, ß- and γ-Na3Sc2(PO4)3:Eu2+ phosphors, which show discrepant phase transformations during heating. The thermal event associated with phase transformation is perceived to be responsible for the observations of abnormal negative thermal quenching performances, in view of the suppression of non-radiative paths by consuming thermal energy during the phenomenon of phase transformation. Our results provide an insight into the relationship between the thermal quenching behaviors and phase transformation details of the Na3Sc2(PO4)3:Eu2+ phosphor and offer a useful clue to exploit high thermal stability phosphors.

Carbon emission flow in networks.

As the human population increases and production expands, energy demand and anthropogenic carbon emission rates have been growing rapidly, and the need to decrease carbon emission levels has drawn increasing attention. The link between energy production and consumption has required the large-scale transport of energy within energy transmission networks. Within this energy flow, there is a virtual circulation of carbon emissions. To understand this circulation and account for the relationship between energy consumption and carbon emissions, this paper introduces the concept of "carbon emission flow in networks" and establishes a method to calculate carbon emission flow in networks. Using an actual analysis of China's energy pattern, the authors discuss the significance of this new concept, not only as a feasible approach but also as an innovative theoretical perspective.