The rapid development of Internet of Things mobile terminals has accelerated the market's demand for portable mobile power supplies and flexible wearable devices. Here, an embedded metal‐mesh ...transparent conductive electrode (TCE) is prepared on poly(ethylene terephthalate) (PET) using a novel selective electrodeposition process combined with inverted film‐processing methods. This embedded nickel (Ni)‐mesh flexible TCE shows excellent photoelectric performance (sheet resistance of ≈0.2–0.5 Ω sq−1 at high transmittance of ≈85–87%) and mechanical durability. The PET/Ni‐mesh/polymer poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS PH1000) hybrid electrode is used as a transparent electrode for perovskite solar cells (PSCs), which exhibit excellent electric properties and remarkable environmental and mechanical stability. A power conversion efficiency of 17.3% is obtained, which is the highest efficiency for a PSC based on flexible transparent metal electrodes to date. For perovskite crystals that require harsh growth conditions, their mechanical stability and environmental stability on flexible transparent embedded metal substrates are studied and improved. The resulting flexible device retains 76% of the original efficiency after 2000 bending cycles. The results of this work provide a step improvement in flexible PSCs.
Research on flexible mobile energy‐supply devices will promote the development of the Internet of Things. An embedded metal nickel (Ni)‐mesh transparent conductive electrode is used as a flexible substrate for perovskite solar cells (PSCs). These Ni‐mesh‐based PSCs exhibit excellent electric properties and remarkable environmental and mechanical stability.
It is quite an important and challenging problem for change detection (CD) from heterogeneous remote sensing images. The images obtained from different sensors (i.e., synthetic aperture radar (SAR) & ...optical camera) characterize the distinct properties of objects. Thus, it is impossible to detect changes by direct comparison of heterogeneous images. In this article, a new unsupervised change detection (USCD) method is proposed based on image translation. The cycle-consistent adversarial networks (CycleGANs) are employed to learn the subimage to subimage mapping relation using the given pair (i.e., before and after the event) of heterogeneous images from which the changes will be detected. Then, we can translate one image (e.g., SAR) from its original feature space (e.g., SAR) to another space (e.g., optical). By doing this, the pair of images can be represented in a common feature space (e.g., optical). The pixels with close pattern values in the before-event image may have quite different values in the after-event image if the change happens on some ones. Thus, we can generate the difference map between the translated before-event image and the original after-event image. Then, the difference map is divided into changed and unchanged parts. However, these detection results are not very reliable. We will select some significantly changed and unchanged pixel pairs from the two parts with the clustering technique (i.e., <inline-formula> <tex-math notation="LaTeX">K </tex-math></inline-formula>-means). These selected pixel pairs are used to learn a binary classifier, and the other pixel pairs will be classified by this classifier to obtain the final CD results. Experimental results on different real datasets demonstrate the effectiveness of the proposed USCD method compared with several other related methods.
Indoles and their derivatives have dominated a significant proportion of nitrogen‐containing heterocyclic compounds and play an essential role in synthetic and medicinal chemistry, pesticides, and ...advanced materials. Compared with conventional synthetic strategies, direct functionalization of indoles provides straightforward access to construct diverse indole scaffolds. As we enter an era emphasizing green and sustainable chemistry, utilizing environment‐friendly solvents represented by water demonstrates great potential in synthesizing valuable indole derivatives. This review aims to depict the critical aspects of aqueous‐mediated indoles functionalization over the past decade and discusses the future challenges and prospects in this fast‐growing field. For the convenience of readers, this review is classified into three parts according to the bonding modes (C−C, C−N, and C−S bonds), which focus on the diversity of indole derivatives, the prominent role of water in the chemical process, and the types of catalyst systems and mechanisms. We hope this review can promote the sustainable development of the direct functionalization of indoles and their derivatives and the discovery of novel and practical organic methods in aqueous phase.
This review aims to depict the critical aspects of aqueous‐mediated indoles functionalization over the past decade and discusses the future challenges and prospects in this fast‐growing field. For the convenience of readers, this review is classified into three parts according to the bonding modes (C−C, C−N, and C−S bonds), which focus on the diversity of indole derivatives, the prominent role of water in the chemical process, and the types of catalyst systems and mechanisms.
Mixed cation/halide perovskites have led to a significant increase in the efficiency and stability of perovskite solar cells. However, mobile ionic defects inevitably exacerbate the photoinduced ...phase segregation and self‐decomposition of the crystal structure. Herein, ultrathin 2D nanosheets of oxo‐functionalized graphene/dodecylamine (oxo‐G/DA) are used to solve ion migration in cesium (Cs)‐formamidinium (FA)‐methylammonium (MA) triple‐cation‐based perovskites. Based on the superconducting carbon skeleton and functional groups that provide lone pairs of electrons on it, the ultrathin 2D network structure can fit tightly on the crystals and wrap them, isolating them, and thus reducing the migration of ions within the built‐in electric field of the perovskite film. As evidence of the formation of sharp crystals with different orientation within the perovskite film, moiré fringes are observed in transmission electron microscopy. Thus, a champion device with a power conversion efficiency (PCE) of 21.1% (the efficiency distribution is 18.8 ± 1.7%) and a remarkable fill factor of 81%, with reduced hysteresis and improved long‐term stability, is reported. This work provides a simple method for the improvement of the structural stability of perovskite in solar cells.
Oxo‐functionalized graphene/dodecylamine is used to solve ion migration in cesium‐formamidinium‐methylammonium triple cation‐base perovskites. The ultra‐thin two‐dimensional network structure can wrap the crystals and reduce the ion migration of the perovskite film. The resulting devices deliver a power conversion efficiency of 21.1%, and a remarkable fill factor of 81%, with reduced hysteresis and improved long‐term stability.
Here we present a 3+2 cycloaddition of rationally designed trisubstituted cyclic α‐chloroamides, primarily those incorporating pharmacological pyrazolone cores, as potent synthons for synthesizing ...valuable spirocyclic γ‐lactam architectures. This protocol exhibits 52–96% yields, impressive substrate compatibility, and scale‐up capacity. Importantly, this study also represents one of the rare examples that harness enaminone C−N bond cleavage to engineer relevant spirocyclic γ‐lactam skeletons of biological interest. Moreover, we propose a plausible mechanistic explanation to elucidate the outstanding chemical outcomes observed, thereby enriching the synthetic toolbox for pyrazolone chemistry and α‐haloamide‐mediated reactions.
Nanostructured CaCO3 modified sewage sludge biochar (CMSSB) was successfully fabricated for efficient removal of Cd(ii) from aqueous solutions. X-ray diffraction (XRD) and scanning electron ...microscopy (SEM) analyses indicated that the loaded CaCO3 mainly existed in the form of dispersive calcite nanoparticles, and the loading of calcite nanoparticles had a slight effect on the morphology of the sewage sludge biochar (SSB). The adsorption capacity of the obtained CMSSB for Cd(ii) based on the Langmuir model is 36.5 mg g−1, which was nearly three times higher than that of the pristine SSB. The adsorption process can be well described by the Elovich model, and the initial adsorption rate of the CMSSB is faster than that of the SSB. The Cd(ii) adsorption mechanism on the CMSSB involves ion-exchange and precipitation reactions between heavy metal ions and calcite nanoparticles and biochar. The present results suggested that the as-prepared CMSSB is an efficient and economic adsorbent for environmental heavy metal remediation.
Since the birth of cyanidation, it has been dominant in the gold extraction industry. Recently, with the increasing awareness of environmental hazards and potential risks posed by the severe toxicity ...of cyanide, attempts to seek alternative lixiviants have arisen. Over the past three decades, a significant amount of literature has examined alternative lixiviants to cyanide for recovering gold, while few industrial applications have been reported due to various obstacles, such as toxicity, excessive consumption, or low leaching efficiency. These obstacles are progressively overcome in multiple ways, including process improvement, system optimization, use of co-intensifying systems, and development of additives. In this paper, related studies about alternative lixiviants and methods such as cyanide, thiosulfate, thiourea, thiocyanate, polysulfides, halides, and microbial leaching are summarized. The history, fundamentals, advancements, and challenges of alternative lixiviants are fully concluded to provide a reference for cleaner gold production. In addition, the comprehensive performance of lixiviants was evaluated according to a novel evaluation criterion proposed in terms of economy, efficiency, and environment.
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•The history and mechanisms of gold lixiviants in gold extraction were reviewed.•A novel evaluation criterion was proposed to evaluate the performance of lixiviants.•The current advances and progress of each lixiviant were summarized.•The challenges and prospects of each lixiviant were forecasted.
Over 60 years of spacecraft exploration has revealed that the Earth's Moon is characterized by a lunar crust
dominated by the mineral plagioclase, overlying a more mafic (richer in iron and ...magnesium) mantle of uncertain composition. Both crust and mantle formed during the earliest stages of lunar evolution when late-stage accretional energy caused a molten rock (magma) ocean, flotation of the light plagioclase, sinking of the denser iron-rich minerals, such as olivine and pyroxene, and eventually solidification
. Very large impact craters can potentially penetrate through the crust and sample the lunar mantle. The largest of these craters is the approximately 2,500-kilometre-diameter South Pole-Aitken (SPA) basin
on the lunar far side. Evidence obtained from orbiting spacecraft shows that the floor of the SPA basin is rich in mafic minerals
, but their mantle origin is controversial and their in situ geologic settings are poorly known. China's Chang'E-4 lunar far-side lander recently touched down in the Von Kármán crater
to explore the floor of the huge SPA basin and deployed its rover, Yutu-2. Here we report on the initial spectral observations of the Visible and Near Infrared Spectrometer (VNIS)
onboard Yutu-2, which we interpret to represent the presence of low-calcium (ortho)pyroxene and olivine, materials that may originate from the lunar mantle. Geological context
suggests that these materials were excavated from below the SPA floor by the nearby 72-km-diameter Finsen impact crater event, and transported to the landing site. Continued exploration by Yutu-2 will target these materials on the floor of the Von Kármán crater to understand their geologic context, origin and abundance, and to assess the possibility of sample-return scenarios.
The effect of spatially modulated interaction on quantum phase transition in one-dimensional interacting spinless fermion system is theoretically investigated by exact diagonalization and density ...matrix renormalization group method. Our calculations show that the periodically modulated interaction can drive the spinless fermion system into topological charge density wave state. The topological state is encoded by quasiparticle end states and the fractional quantized e/2 end charges, and characterized by Berry phase and Chern number. The quasiparticle energy spectra as a function of modulated interaction period appears a stunning fractal-like structure. For the quasi-periodic case, the topological phase transition can also occur. In a word, the spatially modulated interaction can be a new elegant avenue towards realizing to interacting topological phases.
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