Flexible, Transparent and Conductive Metal Mesh Films with Ultra‑High FoM for Stretchable Heating and Electromagnetic Interference Shielding

Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference(EMI)shielding,achieving a flexible EMI shielding film,while maintaining a high transmittance remains a significant challenge.Herein,a flexible,transparent,and conductive copper(Cu)metal mesh film for EMI shielding is fabricated by self-forming crackle template method and electroplating technique.The Cu mesh film shows an ultra-low sheet resistance(0.18Ω□^(-1)),high transmittance(85.8%@550 nm),and ultra-high figure of merit(>13,000).It also has satisfactory stretchability and mechanical stability,with a resistance increases of only 1.3%after 1,000 bending cycles.As a stretchable heater(ε>30%),the saturation temperature of the film can reach over 110°C within 60 s at 1.00 V applied voltage.Moreover,the metal mesh film exhibits outstanding average EMI shielding effectiveness of 40.4 dB in the X-band at the thickness of 2.5μm.As a demonstration,it is used as a transparent window for shielding the wireless communication electromagnetic waves.Therefore,the flexible and transparent conductive Cu mesh film proposed in this work provides a promising candidate for the next-generation EMI shielding applications.

Recent advances in NiO/Ga_(2)O_(3) heterojunctions for power electronics

Beta gallium oxide(β-Ga_(2)O_(3)) has attracted significant attention for applications in power electronics due to its ultrawide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga's figures of merit(BFOM) of more than 3000. Though β-Ga_(2)O_(3) possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga_(2)O_(3)-based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide(NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/β-Ga_(2)O_(3) heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga_(2)O_(3) heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga_(2)O_(3) heterojunctions are discussed. Various device architectures, including the NiO/β-Ga_(2)O_(3) heterojunction pn diodes(HJDs), junction barrier Schottky(JBS) diodes, and junction field effect transistors(JFET), as well as the edge terminations and super-junctions based on the NiO/β-Ga_(2)O_(3) heterojunction, are described.

Band alignment of p-type oxide/ε-Ga2O3 heterojunctions investigated by x-ray photoelectron spectroscopy

Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.

Decarboxylative cyanation and thiocyanation via catalytic electron donor-acceptor complex with copper catalysis

A new catalytic decarboxylative cyanation and thiocyanation via a synergistic Na I/Cu catalysis is developed.The photoexcited electron donor-acceptor complex by assembly of Na I,R3P,and N-acyloxy-phthalimide ester(NHPI ester)triggers the generation of alkyl radical species,which then engages in Cu-catalyzed radical coupling process.Key to success of this dual catalytic transformation is the reliable charge transfer between I·and Cu(I).This dual catalytic platform can eliminate the use of expensive iridium-based photocatalyst or synthetically elaborate organic dyes.A series of primary,secondary,and tertiary alkyl nitriles and thiocyanates are easily synthesized.Moreover,an asymmetric decarboxylative cyanation by applying a chiral Cu catalyst is also developed to afford chiral nitriles in high enantioselectivity.The mechanistic details and the origin of the high enantioselectivity are further investigated by the mechanistic experiments and the density functional theory calculations.

Targetable elements in SARS-CoV-2 S2 subunit for the design of pan-coronavirus fusion inhibitors and vaccines

The ongoing global pandemic of coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS‐CoV‐2),has caused devastating impacts on the public health and the global economy.Rapid viral antigenic evolution has led to the continual generation of new variants.Of special note is the recently expanding Omicron subvariants that are capable of immune evasion from most of the existing neutralizing antibodies(nAbs).This has posed new challenges for the prevention and treatment of COVID-19.Therefore,exploring broad-spectrum antiviral agents to combat the emerging variants is imperative.In sharp contrast to the massive accumulation of mutations within the SARS-CoV-2 receptor-binding domain(RBD),the S2 fusion subunit has remained highly conserved among variants.Hence,S2-based therapeutics may provide effective cross-protection against new SARS-CoV-2 variants.Here,we summarize the most recently developed broad-spectrum fusion inhibitors(e.g.,nAbs,peptides,proteins,and small-molecule compounds)and candidate vaccines targeting the conserved elements in SARS-CoV-2 S2 subunit.The main focus includes all the targetable S2 elements,namely,the fusion peptide,stem helix,and heptad repeats 1 and 2(HR1-HR2)bundle.Moreover,we provide a detailed summary of the characteristics and action-mechanisms for each class of cross-reactive fusion inhibitors,which should guide and promote future design of S2-based inhibitors and vaccines against new coronaviruses.

Crystal structure of SARS-CoV-2 nsp10/nsp162′-O-methylase and its implication on antiviral drug design

Dear Editor,The unexpected outbreak of a novel human coronavirus infection has imposed great threat to public health.Thus far,this newly-identified virus has spread to 215 countries and territories,infected more than 3.5 million people,and caused over 240,000 deaths worldwide.1 Although intensified countermeasures have been implemented globally to control the virus infection,the pandemic is still surging with a daily increase in infection case of over 65,000 ever since April 1st 2020.1 No prophylactic vaccines or clinical drugs are currently available to prevent or treat the disease,namely coronavirus disease 2019(COVID-19).

Characterization of SARS-CoV-2 Omicron spike RBD reveals significantly decreased stability, severe evasion of neutralizing- antibody recognition but unaffected engagement by decoy ACE2 modified for enhanced RBD binding

Dear Editor,The recent-emerging Omicron variant(B.1.1.529 lineage)of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has raised serious public concern because of its rapid regional-and global-transmission.As of 11th January 2022,the Omicron variant has spread to 140 countries,territories or areas through infected air travelers,and the number is continuously increasing.