Electrospun CuS/PVP Nanowires and Superior Near-Infrared Filtration Efficiency for Thermal Shielding Applications

Photo-Stimuli-Responsive CuS Nanomaterials as Cutting-Edge Platform Materials for Antibacterial Applications

Photo-stimuli-responsive therapeutic nanomaterials have gained widespread attention as frontline materials for biomedical applications. The photoactivation strategies are classified as single-modality (based on either reactive oxygen species (ROS)-based photodynamic therapy (PDT), hyperthermia-based photothermal therapy (PTT)), or dual-modality (which combines PDT and PTT). Due to its minimal invasiveness, phototherapy has been extensively applied as an efficient therapeutic platform for many diseases, including skin cancers. However, extensive implementation of phototherapy to address the emergence of multidrug-resistant (MDR) bacterial infections remains challenging. This review focuses on copper sulfide (CuS) nanomaterials as efficient and cost-effective PDT and PTT therapeutic nanomaterials with antibacterial activity. The features and merits of CuS nanomaterials as therapeutics are compared to those of other nanomaterials. Control of the dimensions and morphological complexity of CuS nanomaterials through judicious synthesis is then introduced. Both the in vitro antibacterial activity and the in vivo therapeutic effect of CuS nanomaterials and derivative nanocomposites composed of 2D nanomaterials, polymers, metals, metal oxides, and proteins are described in detail. Finally, the perspective of photo-stimuli-responsive CuS nanomaterials for future clinical antibacterial applications is highlighted. This review illustrates that CuS nanomaterials are highly effective, low-toxic, and environmentally friendly antibacterial agents or platform nanomaterials for combatting MDR bacterial infections.

Advanced Dual-Function Hollow Copper-Sulfide-Based Polyimide Composite Window Film Combining Near-Infrared Thermal Shielding and Organic Pollutants' Photodegradation

Window-film-integrated, near-infrared (NIR) absorption-based nanomaterials are of great interest in terms of numerous demands to reduce energy consumption, especially in buildings and vehicles. However, the question of how to effectively manage thermal energy generated from NIR harvesting in light-absorbing materials, rather than being wasted or causing negative effects, remains challenging. Herein, hollow copper sulfide (Cu2-xS) on colorless polyimide (PI) films, enabling them to be well-dispersed and robustly adhered, underwent in situ growth fabrication and were utilized as NIR-thermal-shielding and organic-pollutant-removal dual-function window films. Due to strong NIR absorbance, arising from the heavy hole-doping (copper cation deficiency), the Cu2-xS/PI composite film exhibited great promise for use in the filtration of the NIR spectrum. By monitoring Cu2-xS densities, its NIR-shielding efficiency reached 69.4%, with hundred-percent UV blocking and consistent performance within the reliability (85 °C/85%RH) tests over one week as well as 5000 bending cycles. The integration of the films into model cars and building windows exhibited excellent thermal-shielding performance upon exposure to direct sunlight. Moreover, benefiting from the distinctive distribution of Cu2-xS, the additional thermal energy (holes) generated in NIR absorption was successfully utilized. The densely surface-confined hollow structure of Cu2-xS on PI significantly endowed good formaldehyde catalytic capacity, with removal efficiency reaching approximately 72% within 60 min and a negligible decline after quartic reuse. These integration methodologies enable the promising fabrication of a high-performance, bifunctional window film combining thermal shielding and indoor organic pollutant removal.

Multilayer Polymer Photonic Aegises Against Near-Infrared Solar Irradiation Heating

Preventing solar heating is nowadays of paramount interest in energy savings and health preservation. For instance, in building thermalization solar heating consumes an excess of energy leading to harmful CO₂ emissions, while in food and beverage packaging it may lead to variation of organoleptic properties or even health issues. The phenomenon is attributed to the large presence of moieties with highly absorbing vibrational overtones and combination bands in the near-infrared spectral region that induces heating in water, moisture, and in polymers used in packaging. Thus, reducing and controlling the light absorbed by these materials with effective low-cost passive systems can play a major role in energy saving and health preservation. In this work, different polymer dielectric mirrors are reported, made of poly(N-vinylcarbazole) and either cellulose acetate or poly(acrylic acid), and able to selectively reflect near-infrared radiation while maintaining high transparency in the visible range. To this end, simple, tandem, and superperiodic mirrors are used to shield radiation impinging on samples of water and paraffin, demonstrating shielding efficiencies up to 52% with respect to unshielded references, promising a new paradigm to solve thermal management issues.

Transition metal sulfides meet electrospinning: versatile synthesis, distinct properties and prospective applications

One-dimensional (1D) electrospun nanomaterials have attracted significant attention due to their unique structures and outstanding chemical and physical properties such as large specific surface area, distinct electronic and mass transport, and mechanical flexibility. Over the past years, the integration of metal sulfides with electrospun nanomaterials has emerged as an exciting research topic owing to the synergistic effects between the two components, leading to novel and interesting properties in energy, optics and catalysis research fields for example. In this review, we focus on the recent development of the preparation of electrospun nanomaterials integrated with functional metal sulfides with distinct nanostructures. These functional materials have been prepared via two efficient strategies, namely direct electrospinning and post-synthesis modification of electrospun nanomaterials. In this review, we systematically present the chemical and physical properties of the electrospun nanomaterials integrated with metal sulfides and their application in electronic and optoelectronic devices, sensing, catalysis, energy conversion and storage, thermal shielding, adsorption and separation, and biomedical technology. Additionally, challenges and further research opportunities in the preparation and application of these novel functional materials are also discussed.

Biomass-Derived Bilayer Solar Evaporator with Enhanced Energy Utilization for High-Efficiency Water Generation

Solar-driven evaporation has been recognized as a promising approach to address global crises of drinking water via virtue of abundant and green solar energy. However, a great challenge still exists for achieving efficient usage of solar energy combined with fast water evaporation. Here, a double-structural solar evaporator consists of an upper copper sulfide (CuS) agar-based aerogel and a bottom molybdenum carbide/carbon (MoCC) composite of cotton fibers-derived aerogel (CuSAA/MoCCFA), which is constructed for solar evaporation. The CuS layer performs as a solar-thermal converter with efficient light adsorption and prominent thermally localized ability, while the bottom layer (superhydrophilic porous aerogel) guarantees sufficient water transportation and excellent thermal insulation. The fully integrative solar evaporator has an attractive water evaporation rate of 2.44 kg m^-2 h^-1 with a superb solar-thermal conversion efficiency of 92.77% under 1 sun illumination. More notably, the bilayer aerogel exhibits long-term durability in high-salinity media during solar-driven desalination. In addition, a solar absorber assisted with low-temperature phase change materials comprise the solar evaporation system, which is aimed at solar-thermal energy storage and reutilization for conquering solar intermittence. Such superior performance of a comprehensive solar desalination system provides a new avenue for highly efficient and suitable clean water production under natural sunlight conditions.

Dynamic Response Systems of Healthcare Mask Production to COVID-19: A Case Study of Korea

Korea initiated a new experiment, called a dynamic response system for open democratic societies as a principle to respond to the novel coronavirus (COVID-19). The global pandemic of COVID-19 led to a surge in demand for healthcare medical masks and respirators, and strained the global supply chain of mask production and distribution systems. This study provides a systemic view of critical personal protective equipment for both healthcare staff and the public to stop the spread of COVID-19. This study investigates the dynamic response system of healthcare mask production to the coronavirus and discusses lessons learned in view of systems thinking. The study shows that it is critical to developing a quick and dynamic response system to the evolving market conditions with flexible and agile operations. Visibility with transparency with information sharing with the public is also critical under global pandemic. Due to the shortage of mask supply, smart consumption is required along with collaboration with public and private sectors, as well as global organizations. Democratic leadership and a well-prepared strategic plan for long-term period are essential to the open society to prepare the global pandemic in the future. This study serves as a benchmark for dynamic and timely responses to the global pandemic.

Solvothermal Synthesis and Near-Infrared Shielding Properties of Cs0.3WO3/WO3 Composites

The Cs[Formula: see text]WO3/WO3 composite with near-infrared shielding properties was synthesized by the solvothermal method using tungstic acid and cesium salt as raw materials. The as-prepared composites were tested by X-ray powder diffraction, scanning electron microscopy, energy spectrum analysis, transmission electron microscopy, electron energy loss spectroscopy, and ultraviolet-visible near-infrared spectroscopy. The effects of different reaction conditions on the structure and near-infrared shielding properties of the synthesized composites were investigated. The best near-infrared light transmittance of as-prepared composites can reach up to 9%, which provides a feasible solution for the near-infrared shielding material. The new homogeneous composites of cesium tungsten bronze and tungsten oxide are good candidates for solar filters.

ITO@SiO2 and ITO@{M6Br12}@SiO2 (M = Nb, Ta) nanocomposite films for ultraviolet-near infrared shielding

Transparent optical thin films for energy saving applications have recently gained substantial prominence for functional window processes. In this study, highly visible transparent nanocomposite films with ultraviolet (UV) and near-infrared (NIR) blocking capabilities are reported. Such nanocomposite films, prepared by electrophoretic deposition on ITO-coated glass, are composed of indium tin oxide (ITO) nanocrystals (9 nm) and octahedral metal atom clusters (1 nm, Nb₆ or Ta₆) embedded into silica nanoparticles (∼80 nm). The functional silica nanoparticles were prepared by a reverse microemulsion process. The microstructural characterization proved that ITO nanocrystals are centered in the silica nanoparticles, whereas the metal atom clusters are homogeneously distributed in the silica matrix. The optical absorption spectra of these transparent nanocomposite films exhibit distinct and complementary contributions from their ITO nanoparticles and metal atom clusters (absorption in the UV range) and from the ITO layer on silica.

Morphology and phase evolution from CuS to Cu1.8S in a hydrothermal process and thermoelectric properties of Cu1.8S bulk

CuS microflowers self-assembled from nanosheets were prepared by hydrothermal synthesis (HS) using CuCl₂·2H₂O and CS(NH₂)₂ as raw materials and glycol as a solvent at 120 and 140 °C for 1.5 h.