Ultrahigh Bipolar Photoresponse in a Self-Powered Ultraviolet Photodetector Based on GaN and In/Sn-Doped Ga2O3 Nanowires pn junction.

Self-powered ultraviolet photodetectors with bipolar photoresponse have great potential in the fields of ultraviolet optical communication, all-optical controlled artificial synapses, high-resolution ultraviolet imaging equipment, and multiband photoelectric detection. However, the current low optoelectronic performance limits the development of such polar switching devices. Here, we construct a self-powered ultraviolet photodetector based on GaN and In/Sn-doped Ga2O3 (IGTO) nanowires (NWs) pn junction structure. This unique nanowire/thin film structure allows GaN and IGTO to dominate the absorption of light at different wavelengths, resulting in a highly bipolar photoresponse. The device has a responsivity of 2.04 A/W and a normalized detectivity of 7.18 × 1013 Jones at 254 nm and a responsivity of -2.09 A/W and a normalized detectivity of -7 × 1013 Jones at 365 nm, both at zero bias. In addition, it has an extremely high Ilight/Idark ratio of 1.05 × 105 and ultrafast response times of 2.4/1.9 ms (at 254 nm) and 5.7/5.2 ms (at 365 nm). These excellent properties are attributed to the high specific surface area of the one-dimensional nanowire structure and the abundant voids generated by the nanowire network to enhance the absorption of light, and the p-n junction structure enables the rapid separation and transfer of photogenerated electron-hole pairs. Our findings provide a feasible strategy for high-performance wavelength-controlled polarity switching devices.

Enhanced Light Absorption and Photo-Generated Charge Separation Efficiency for Boosting Photocatalytic H2 Evolution through TiO2 Quantum Dots with N-Doping and Concomitant Oxygen Vacancy.

Low-range light absorption and rapid recombination of photo-generated charge carriers have prevented the occurrence of effective and applicable photocatalysis for decades. Quantum dots (QDs) offer a solution due to their size-controlled photon properties and charge separation capabilities. Herein, well-dispersed interstitial nitrogen-doped TiO2 QDs with stable oxygen vacancies (N-TiO2-x-VO) are fabricated by using a low-temperature, annealing-assisted hydrothermal method. Remarkably, electrostatic repulsion prevented aggregation arising from negative charges accumulated in situ on the surface of N-TiO2-x-VO, enabling complete solar spectrum utilization (200-800 nm) with a 2.5 eV bandgap. Enhanced UV-vis photocatalytic H2 evolution rate (HER) reached 2757 µmol g-1 h-1, 41.6 times higher than commercial TiO2 (66 µmol g-1 h-1). Strikingly, under visible light, HER rate was 189 µmol g-1 h-1. Experimental and simulated studies of mechanisms reveal that VO can serve as an electron reservoir of photo-generated charge carriers on N-doped active sites, and consequently, enhance the separation rate of exciton pairs. Moreover, the negative free energy (-0.35 V) indicates more favorable thermodynamics for HER as compared with bulk TiO2 (0.66 V). This research work paves a new way of developing efficient photocatalytic strategies of HER that are applicable in the sustainable carbon-zero energy supply.

Tunable High-Sensitivity Four-Frequency Refractive Index Sensor Based on Graphene Metamaterial.

As graphene-related technology advances, the benefits of graphene metamaterials become more apparent. In this study, a surface-isolated exciton-based absorber is built by running relevant simulations on graphene, which can achieve more than 98% perfect absorption at multiple frequencies in the MWIR (MediumWavelength Infra-Red (MWIR) band as compared to the typical absorber. The absorber consists of three layers: the bottom layer is gold, the middle layer is dielectric, and the top layer is patterned with graphene. Tunability was achieved by electrically altering graphene's Fermi energy, hence the position of the absorption peak. The influence of graphene's relaxation time on the sensor is discussed. Due to the symmetry of its structure, different angles of light source incidence have little effect on the absorption rate, leading to polarization insensitivity, especially for TE waves, and this absorber has polarization insensitivity at ultra-wide-angle degrees. The sensor is characterized by its tunability, polarisation insensitivity, and high sensitivity, with a sensitivity of up to 21.60 THz/refractive index unit (RIU). This paper demonstrates the feasibility of the multi-frequency sensor and provides a theoretical basis for the realization of the multi-frequency sensor. This makes it possible to apply it to high-sensitivity sensors.

Dual-Parasitic Effect Enables Highly Reversible Zn Metal Anode for Ultralong 25,000 Cycles Aqueous Zinc-Ion Batteries.

The use of electrolyte additives is an efficient approach to mitigating undesirable side reactions and dendrites. However, the existing electrolyte additives do not effectively regulate both the chaotic diffusion of Zn2+ and the decomposition of H2O simultaneously. Herein, a dual-parasitic method is introduced to address the aforementioned issues by incorporating 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIm]OTf) as cosolvent into the Zn(OTf)2 electrolyte. Specifically, the OTf- anion is parasitic in the solvent sheath of Zn2+ to decrease the number of active H2O. Additionally, the EMIm+ cation can construct an electrostatic shield layer and a hybrid organic/inorganic solid electrolyte interface layer to optimize the deposition behavior of Zn2+. This results in a Zn anode with a reversible cycle life of 3000 h, the longest cycle life of full cells (25,000 cycles), and an extremely high initial capacity (4.5 mA h cm-2), providing a promising electrolyte solution for practical applications of rechargeable aqueous zinc-ion batteries.

Concentration-Driven Interfacial Amorphization toward Highly Stable and High-Rate Zn Metal Batteries.

The interfacial structure holds great promise in suppressing dendrite growth and parasitic reactions of zinc metal in aqueous media. Current advancements prioritize novel component fabrication, yet the local crystal structure significantly impacts the interfacial properties. In addition, there is still a critical need for scalable synthesis methods for expediting the commercialization of aqueous zinc metal batteries (AZMBs). Herein, we propose a scalable concentration-controlled method for realizing crystalline to amorphous transformation of the Zn metal interface with exceptional scalability (>1 m2) and processing consistency (>30 trials). Theoretical and experimental analyses highlight the advantages of amorphous ZnO, which exhibits moderate adsorption energy, strong desolvation ability, and hydrophilicity. Employing the amorphous ZnO-coated zinc metal anode (AZO-Zn) significantly enhances the cycling performance, impressively maintaining 1000 cycles at 100 mA cm-2. The prototype AZO-Zn||MnO2@CNT pouch cell demonstrates a capacity of 15.7 mAh and maintains 91% of its highest capacity over 100 cycles, presenting promising avenues for the future commercialization of AZMBs.

MoP quantum dots based multifunctional efficient electrocatalyst for stable and long-life flexible lithium-sulfur batteries.

The commercialization of lithium-sulfur (Li-S) batteries is challenging, owing to factors like the poor conductivity of S, the 'shuttle effect', and the slow reaction kinetics. To address these challenges, MoP quantum dots were decorated on hollow carbon spheres (MoPQDs/C) in this study and used as an efficient lithium polysulfides (LiPSs) adsorbents and catalysts. In this approach polysulfides are effectively trapped through strong chemisorption and physical adsorption while simultaneously facilitating LiPSs conversion by enhancing the reaction kinetics. MXene serves as a flexible physical barrier (MoPQDs/C@MXene), further enhancing the confinement of LiPSs. Moreover, both materials are conductive, significantly facilitating electron and charge transfer. Additionally, the flexible MoPQDs/C@MXene-S electrode offers a large specific surface area for sulfur loading and withstand volume expansion during electrochemical processes. As a result, the MoPQDs/C@MXene-S electrode exhibits excellent long-term cyclability and maintains a robust specific capacity of 992 mA h g-1 even after 800cycles at a rate of 1.0C (1C = 1675 mA g-1), with a minimal capacity decay rate of 0.034 % per cycle. This work proposes an efficient strategy to fabricate highly efficient electrocatalysts for advanced Li-S batteries.

Application of Inorganic Quantum Dots in Advanced Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have emerged as one of the most attractive alternatives for post-lithium-ion battery energy storage systems, owing to their ultrahigh theoretical energy density. However, the large-scale application of Li-S batteries remains enormously problematic because of the poor cycling life and safety problems, induced by the low conductivity , severe shuttling effect, poor reaction kinetics, and lithium dendrite formation. In recent studies, catalytic techniques are reported to promote the commercial application of Li-S batteries. Compared with the conventional catalytic sites on host materials, quantum dots (QDs) with ultrafine particle size (<10 nm) can provide large accessible surface area and strong polarity to restrict the shuttling effect, excellent catalytic effect to enhance the kinetics of redox reactions, as well as abundant lithiophilic nucleation sites to regulate Li deposition. In this review, the intrinsic hurdles of S conversion and Li stripping/plating reactions are first summarized. More importantly, a comprehensive overview is provided of inorganic QDs, in improving the efficiency and stability of Li-S batteries, with the strategies including composition optimization, defect and morphological engineering, design of heterostructures, and so forth. Finally, the prospects and challenges of QDs in Li-S batteries are discussed.

Composition-dependent activity of Mn-doping NiS2 nanosheets for boosting photocatalytic H2 evolution.

Two-dimensional transition metal disulfides are excellent photocatalytic materials, which can be significantly improved by optimizing the composition and structure. Herein, Mn-doping NiS2 of (Ni1-xMnx)-S with various Ni/Mn molar ratios is proposed via a facile and low-cost solvothermal method. The optimal (Ni4/6Mn2/6)-S exhibits pinecone-like morphology composed of tiny nanosheets with enlarged active sites, which facilitates the separation of photoinduced electrons and holes, improves the electron transfer ability and conductivity, and enlarges the active sites compared with pure NiS2 and MnS. Also, the negative shift of the conduction band derived from Mott-Schottky plots and the empirical formula provides a high thermodynamic driving force for hydrogen catalytic reaction. (Ni4/6Mn2/6)-S performs an ultrahigh hydrogen evolution rate of 24.86 mmol g-1 h-1 under UV-visible light irradiation, which is 1.5 times higher than pure NiS2 (16.92 mmol g-1 h-1) and 2.3 times higher than pure MnS (10.69 mmol g-1 h-1). The outstanding repeatability of 86.7% retention and apparent quantum yield of 46.9% are also achieved. Therefore, this work offers a novel bimetallic sulfide of (Ni1-xMnx)-S to improve the conversion efficiency of solar energy to chemical energy for photocatalytic hydrogen production.

High-efficiency photoreduction of CO2 in a low vacuum.

Photoreduction of CO2 into CO, CH4 or hydrocarbons is attractive, due to environmental compatibility and economic feasibility. Optimizing the reaction engineering of CO2 reduction is an effective and general strategy that should be given special consideration. In this article, the photocatalytic CO2 reduction performances are originally investigated in a low vacuum in both dilute (10%) and pure CO2. We discover that the CH4 yield increased above one hundred times as the vacuum degree increased from barometric pressure to -80 kPa in dilute CO2. It also reveals long-term stability and good cycling performance in a low vacuum. The enhanced CO2 photoreduction performance in a low vacuum comes from better accumulation of photogenerated electrons, less intense Brownian movement of gas molecules in the environment and hindrance of the active site-blocking of gas molecules in the environment. Improved photocatalytic CO2 reduction in a low vacuum is further verified by Pt-TiO2 catalysts. This research presents a general route for producing clean fuels by photocatalytic CO2 reduction in a more effective way.

Fusion Bonding Possibility for Incompatible Polymers by the Novel Ultrasonic Welding Technology: Effect of Interfacial Compatibilization.

Fusion bonding for polymers has been successfully welded for the same and dissimilar materials. However, it is difficult to bond incompatible polymers due to poor interfacial adhesion. Usually, interfacial compatibilization can resolve this problem. According to the mechanism, an interlayer solder sheet (ISS) consisting of maleic anhydride-functionalized polypropylene (PP-g-MAH) and polyamide6 (PA6) was introduced into the ultrasonic welding (USW) device. In this way, it successfully realized the weldability between PP and PA6. The welding strength of PP-PA6 reached 22.3 MPa, about 84% welding strength for the PP body and 63% tensile strength for PP. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) showed the formation of PP-g-PA6 copolymer in blends. This copolymer played the role of an emulsifier, which enhanced the interfacial adhesion between PP and PA6 in two phases, leading to micron-scale homogeneity. In the USW process, the copolymer could act as a bridge between PP and PA6 molecular chains to realize the fusion bonding of incompatible polymers. Finally, we proposed the fusion bonding model for PP-PA6 interfaces.

Copper-mediated synthesis of fullerooxazoles from [60]fullerene and N-hydroxybenzimidoyl cyanides.

A novel and efficient copper-mediated [3 + 2] heteroannulation reaction of [60]fullerene with N-hydroxybenzimidoyl cyanides has been developed for the synthesis of fullerooxazoles. A possible reaction mechanism involving unique C-CN and N-OH bond cleavages and subsequent C-OH bond formation for N-hydroxybenzimidoyl cyanides is proposed to explain the generation of fullerooxazoles. In addition, the formed fullerooxazoles can be further electrochemically transformed into amidated 1,2-hydrofullerenes.

Unexpected Diels-Alder reaction of [60]fullerene with electron-deficient ferrocenes as cyclopentadiene surrogates.

The unexpected Diels-Alder reaction of [60]fullerene (C60) with ferrocenes bearing electron-withdrawing groups as cyclopentadiene surrogates has been developed to selectively afford single isomers of [2 + 4] cycloadducts of C60. Mechanistic studies indicate that cyclopentadienes are in situ generated from electron-deficient ferrocenes in the presence of an oxidant and an acid, followed by [2 + 4] cycloadditions with dienophiles. A Michael addition reaction using a Grignard reagent has been utilized to transform the Diels-Alder adducts of C60 into more stable fullerene derivatives.

Yellow Wine Polyphenolic Compound Protects Against Doxorubicin-Induced Cardiotoxicity by Modulating the Composition and Metabolic Function of the Gut Microbiota.

BACKGROUND: Dietary polyphenols help to prevent cardiovascular diseases, and interactions between polyphenols and gut microbiota are known to exist. In this study, we speculated that gut microbiota-mediated metabolite regulation might contribute to the anticardiotoxic effects of yellow wine polyphenolic compound (YWPC) in doxorubicin (DOX)-treated rats. METHODS: 16S-rDNA sequencing was performed to analyze the effects of YWPC on the gut microbiota in DOX-treated rats (n=6). Antibiotics were used to investigate the contribution of the altered microbiome to the role of YWPC (n=6). Plasma metabolomics were also analyzed by untargeted gas chromatography-mass spectrometry systems. RESULTS: YWPC ameliorated DOX-mediated cardiotoxicity, as evidenced by increased cardiac and mitochondrial function and reduced levels of inflammation and myocardial apoptosis (P<0.05 for all). The low abundance of Escherichia-Shigella, Dubosiella, and Allobaculum, along with enrichment of Muribaculaceae_unclassified, Ralstonia, and Rikenellaceae_RC9_gut_group in the gut, suggested that YWPC ameliorated DOX-induced microbial dysbiosis. YWPC also influenced the levels of metabolites altered by DOX, resulting in lower arachidonic acid and linoleic acid metabolism and higher tryptophan metabolite levels (P<0.05 for all). Correlational studies indicated that YWPC alleviated DOX-induced inflammation and mitochondrial dysfunction by modulating the gut microbial community and its associated metabolites. Antibiotic treatment exacerbated cardiotoxicity in DOX-treated rats, and its effect on the gut microbiota partly abolished the anticardiotoxic effects of YWPC, suggesting that the microbiota is required for the cardioprotective role of YWPC. CONCLUSIONS: YWPC protected against DOX-induced cardiotoxicity in a gut microbiota-dependent manner. This supports the use of dietary polyphenols as a therapeutic approach for the treatment of cardiovascular diseases via microbiota regulation.

A copper-promoted synthesis of epoxy-bridged [60]fullerene-fused lactones and further derivatization.

A facile copper-promoted decarboxylative annulation of [60]fullerene (C60) with two identical α-oxocarboxylic acids via an unprecedented cascade addition pathway has been exploited to synthesize the unique epoxy-bridged C60-fused lactones for the first time. Further transformations into the rare epoxy-bridged C60-fused hemiacetals and bicyclic-fused 1,2,3,4-adducts as well as application in a perovskite solar cell device of the obtained products have also been demonstrated. The structures of the epoxy-bridged C60-fused lactones and derived reductive products have been unequivocally established by single-crystal X-ray crystallography. Plausible reaction mechanisms leading to the observed products are proposed.

Cu(I)-Catalyzed Synthesis of [60]Fullerene-Fused Lactams and Further Electrochemical Functionalization.

A novel and efficient Cu(I)-catalyzed radical heteroannulation reaction of [60]fullerene (C60) with α-bromo acetamides has been disclosed for the direct synthesis of diverse C60-fused lactams. Furthermore, the formed C60-fused lactams can be served as a versatile platform for further electrochemical functionalization to prepare 1,2-, 1,4-, 1,2,3,16-, and 1,4,9,25-adducts of C60. In addition, a representative fullerene product has been applied as an overcoating layer of the electron-transporting layer in n-type perovskite solar cell.

Hybrid structure of PbS QDs and vertically-few-layer MoS2 nanosheets array for broadband photodetector.

A novel three-dimensional (3D) vertically-few-layer MoS2 (V-MoS2) nanosheets- zero-dimensional PbS quantum dots (QDs) hybrid structure based broadband photodetector was fabricated, and its photoelectric performance was investigated in detail. We synthesized the V-MoS2 nanosheets by chemical vapor deposition, using the TiO2 layer as the induced layer, and proposed a possible growth mechanism. The use of the TiO2 induction layer successfully changed the growth direction of MoS2 from parallel to vertical. The prepared V-MoS2 nanosheets have a large specific surface area, abundantly exposed edges and excellent light absorption capacity. The V-MoS2 nanosheets detector was then fabricated and investigated, which exhibits a high sensitivity for 635 nm light, a fast response time and an excellent photoelectric response. The V-MoS2 nanosheets with a height of approximately 1 µm successfully broke the light absorption limit caused by the atomic thickness. Finally, we fabricated the PbS QDs/V-MoS2 nanosheets hybrid detector and demonstrated their potential for high-performance broadband photodetectors. The response wavelength of the hybrid detector extends from the visible band to the near-infrared band. The responsivity of the hybrid detector reaches 1.46 A W-1 under 1450 nm illumination. The combination of 3D MoS2 nanosheets and QDs further improves the performance of MoS2-based photodetector devices. We believe that the proposed zero-dimensional QDs and 3D vertical nanosheets hybrid structure broadband photodetector provides a promising way for the next-generation optoelectronic devices.

Self-catalyst ß-Ga2O3 semiconductor lateral nanowire networks synthesis on the insulating substrate for deep ultraviolet photodetectors.

Monoclinic gallium oxide (ß-Ga2O3) is a super-wide bandgap semiconductor with excellent chemical and thermal stability, which is an ideal candidate for detecting deep ultraviolet (DUV) radiation (100-280 nm). The growth of ß-Ga2O3 is challenging and most methods require Au as the catalyst and a long reacting time (more than 1 hour). In this work, the self-catalyst ß-Ga2O3 lateral nanowire networks were synthesized on an insulating substrate rapidly by a simple low-cost Chemical Vapor Deposition (CVD) method. A thin film of ß-Ga2O3 nanowire networks was synthesized within a reacting time of 15 minutes, which possesses a huge possibility for the rapid growth of ß-Ga2O3 metal oxide nanowires networks and application in the future solar-blind photodetector. MSM (metal-semiconductor-metal) photodetectors based on the ß-Ga2O3 nanowire networks revealed fast response (on-off ratios is about 103), which is attributed to the unique cross-junction barrier-dominated conductance of the nanowire networks. In addition, the self-catalyst ß-Ga2O3 nanowires grown on insulating SiO2 are achieved and could be expected to find important applications in a bottom-up way of fabricating the next generation semiconductor nanoelectronics.