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Graphene has attracted increasing attention due to its unique electrical, optical, optoelectronic, and mechanical properties, which have opened up huge numbers of opportunities for applications. An overview of the recent research on graphene and its derivatives is presented, with a particular focus on synthesis, properties, and applications in solar cells. [ABSTRACT FROM AUTHOR]

Reduced Graphene Oxide (rGO) has the distinct advantage of an aqueous and industrial-scalable production route. However large deviation in the electrical resistivity of fabricated rGO devices, caused by inhomogeneous coverage of rGO on the substrate, prevents its practical application in electronic devices. This critical problem could be solved by using an ethanol chemical vapour deposition (CVD) treatment on graphene oxide (GO). With the treatment, not only GO is reduced to rGO, but also rGO preferentially grows outwards from the edges of the existing GO template and enlarge in size until rGO completely covers the substrate. The growth sequence is presented and our results indicate that the growth supports the free radical condensate growth mechanism. After the ethanol CVD treatment, the standard deviation in electrical resistivity decreased significantly by 99.95% (1.60 × 106 to 7.72 × 102Ω per square) in comparison with hydrazine-reduced rGO substrates. As no carbon signatures on the substrate were observed when no template was used, this work indicates that GO could act as a template for subsequent formation of rGO. [ABSTRACT FROM AUTHOR]

The palladium‐catalyzed reaction of aromatic amides with maleimides results in the formation of a double C−H bond activation product, which occurs at both the benzylic and meta positions. Computational chemistry studies suggest that the first C−H bond activation unfolds via a six‐membered palladacycle, maleimide insertion, protonation of the Pd−N bond, and then activation of the meta C−H bond. The process concludes with reductive elimination, producing an annulation product. The energy decomposition analysis (EDA) showed that the deformation energy favors the ortho C−H bond activation process. However, this route is non‐productive. The interaction energy controls the site where the maleimide is inserted into the Pd−C(sp3) bond, which determines its site selectivity. The energetic span model indicates that the meta C−H bond activation step is the one that determines the turnover frequency. Regarding the directing group, it has been concluded that the strong Pd−S bonding and the destabilizing effect of the deformation energy allow the 2‐thiomethylphenyl to function effectively as a directing group. [ABSTRACT FROM AUTHOR]

Incremental die forming is a novel flexible forming process for fabricating large integral panels in which a pair of smaller tools is used to press the large structure multiple times at different positions. However, during each pressing, the material of the flange region shrinks in the circumferential direction because of the flow into the die, and thus it tends to wrinkle. In this study, the wrinkling behavior in the flange region of the polygonal panel deformed in a relatively smaller spherical die was predicted by a theoretical approach that determined the moment when the circumferential stress reached the critical wrinkle limit. The stress distribution of the flange region was derived by considering the plastic behavior reflected by the plastic modulus and shear stress component caused by the nonaxisymmetric shape. The critical circumferential wrinkle stress of the stiffened flange skin was calculated using the energy method. Both stresses are related to the radial dimension of the panel edge, which varies with the punch stroke. Therefore, the critical stroke during the pressing process was obtained and verified by finite element model simulations and experiments on regular hexagonal and square flanged panels, proving the accuracy and efficiency of the approach. The factors affecting the wrinkling behavior, including the forming radius, die size, and panel size, were then investigated through a theoretical analysis and simulations. This approach provides a valuable reference for the design of appropriate punch strokes that can prevent severe flange wrinkles during incremental die forming. [Display omitted] • A theoretical approach is proposed for predicting the plastic wrinkle of stiffened panel in spherical die forming. • The plastic stress in the flange region is calculated considering shear stress and strain hardening. • Critical punch stroke is predicted based on the energy method and verified by simulations and experiments. • This efficient approach guides the process scheme of each incremental die forming pass. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) sheet is used as a novel substrate for dip-pen nanolithography (DPN). After GO is transferred onto SiO2using the Langmuir–Blodgett technique, CoCl2is patterned on both GO and exposed SiO2substrates simultaneously by DPN, which is used for growth of different structured carbon nanotubes. [ABSTRACT FROM AUTHOR]

Hydraulic excitation causes abnormal head-cover vibration in some pump-turbines, particularly as design heads continue to rise. Pump-turbines with heads exceeding 600 m have reported such vibrations in pump mode, and it is urgent to reveal the reasons. A study was conducted on a head-cover of a pump-turbine with a maximum head of 660 m by 3D computational fluid dynamics (CFD) and finite element method (FEM) numerical simulations to investigate the hydraulic excitation source and vibration mechanism. Results show that the intensive vibration is related to the coincidence of frequency and mode between abnormal pressure pulsations with frequency 6–8fn and the low-order wet mode of the head-cover. A new flow pattern termed the rolling vortex was discovered in the vaneless space under high-head pumping conditions. The 6–8fn pressure pulsations result from the interaction between rolling vortices and guide-vanes, similar to the rotor-stator interaction. The flow mechanism of the rolling vortices is that the outflow velocity near the hub at the runner outlet is higher than that near the shroud, due to the positive blade lean angle and the X-shape distorted blades. Suppressing rolling vortices may help eliminate the abnormal head-cover vibration, which will be attempted in further study. [ABSTRACT FROM AUTHOR]

Developing the films of N‐containing unsubstituted poly(p‐phenylene) (PPP) films for diverse applications is significant and highly desirable because the replacement of sp2 C atoms with sp2 N atoms will bring novel properties to the as‐prepared polymers. In this research, an electrochemical‐dehalogenation polymerization strategy is employed to construct two N‐containing PPP films under constant potentials, where 2,5‐diiodopyridine (DIPy) and 2,5‐dibromopyrazine (DBPz) are used as starting agents. The corresponding polymers are named CityU‐23 (for polypyridine) and CityU‐24 (for polypyrazine). Moreover, it is found that both polymers can form films in situ on different conductive substrates (i.e., silicon, gold, ITO, and nickel), satisfying potential device fabrication. Furthermore, the as‐obtained thin films of CityU‐23 and CityU‐24 exhibit good performance of alkaline hydrogen evolution reaction with the overpotential of 212.8 and 180.7 mV and the Tafel slope of 157.0 and 122.4 mV dec−1, respectively. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

Twinning commonly exists in noble metals. In recent years, it has attracted increasing interest as it is powerful to tune the physicochemical properties of metallic nanomaterials. To the best of our knowledge, all the reported twinned noble metal structures exclusively possess the close-packed {111} twinning plane. Here, we report the discovery of non-close-packed twinning planes in our synthesized Au nanokites. By using the bent Au nanoribbons with unique 4H/face-centered cubic)/4H crystal-phase heterostructures as templates, Au nanokites with unusual twinned 4H-phase structures have been synthesized, which possess the non-close-packed {10 1 ¯ 2} or {10 1 ¯ 6} twinning plane. By using the Au nanokites as templates, twinned 4H-phase Au@Ag and Au@PdAg core-shell nanostructures have been synthesized. The discovery of 4H-phase twinned noble metal nanostructures may pave a way for the preparation of metal nanomaterials with unique twinned structures for various promising applications. Twinning is a powerful approach to engineering the physicochemical properties of metallic nanomaterials. Here, the authors discover unusual non-close-packed twinning planes in 4H-phase gold nanokites and show that they can be used as templates to grow 4H-phase twinned nanostructures of other noble metals. [ABSTRACT FROM AUTHOR]

The ultraviolet-induced degradation (UVID), with losses of up to 11 % after 2000 h-exposure (Sinha et al., 2023) [1], impairs long-term stability of silicon heterojunction (SHJ) solar cells at present. However, the mechanism of UVID has remained only roughly understood till now. Herein, we shed light on the electrical properties of defects in SHJ solar cells to elucidate the underlying mechanism. Defect generation in SHJ solar cells after ultraviolet (UV) irradiation can be observed from photoluminescence (PL) images. Furthermore, we extract the density of states near Fermi level in hydrogenated amorphous silicon (a -Si:H) through analyzing carrier transport mechanism, and find the increment of state density induced by the UV irradiation. In conjunction with Fourier-transform infrared (FTIR) spectra, we ascribe the UV-induced defects to the rupture of Si–H and Si–H 2 bonds. Besides, the intersection point between Fermi levels of the c -Si and a -Si:H/ c -Si interface can be found shift toward valence band from admittance spectrum analysis, which is the cause of the higher interface state density based on the theory of Fermi energy dependent hydrogen diffusion energy. As a result, a potential mechanism of generation of recombination centers responsible for UVID in SHJ solar cells is proposed, which could provide insights into the possible solutions for UVID and enhance the long-term stability of SHJ solar cells. • We have qualitatively and quantitatively investigated the generation of induced defects during ultraviolet-induced degradation (UVID) process in silicon heterojunction (SHJ) solar cells. • The UV irradiation induce bond rupture of Si–H and Si–H 2 in hydrogenated amorphous silicon (a -Si:H) film, which brings about higher density of states near Fermi level. • The UV irradiation induce the shift of Fermi level position at the interface of a -Si:H/ c -Si, which decreases the formation enthalpy of H-related defects and leads to higher interface state density. [ABSTRACT FROM AUTHOR]

Wet‐chemical synthesis refers to the bottom‐up chemical synthesis in solution, which is among the most popular synthetic approaches towards functional two‐dimensional (2D) materials. It offers several advantages, including cost‐effectiveness, high yields,, precious control over the production process. As an emerging family of 2D materials, elemental 2D materials (Xenes) have shown great potential in various applications such as electronics, catalysts, biochemistry,, sensing technologies due to their exceptional/exotic properties such as large surface area, tunable band gap,, high carrier mobility. In this review, we provide a comprehensive overview of the current state‐of‐the‐art in wet‐chemical synthesis of Xenes including tellurene, bismuthene, antimonene, phosphorene,, arsenene. The current solvent compositions, process parameters utilized in wet‐chemical synthesis, their effects on the thickness, stability of the resulting Xenes are also presented. Key factors considered involves ligands, precursors, surfactants, reaction time, temperature. Finally, we highlight recent advances, existing challenges in the current application of wet‐chemical synthesis for Xenes production, provide perspectives on future improvement. [ABSTRACT FROM AUTHOR]

Crystal phase, a critical structural characteristic beyond the morphology, size, dimension, facet, etc., determines the physicochemical properties of nanomaterials. As a group of layered nanomaterials with polymorphs, transition metal dichalcogenides (TMDs) have attracted intensive research attention due to their phase-dependent properties. Therefore, great efforts have been devoted to the phase engineering of TMDs to synthesize TMDs with controlled phases, especially unconventional/metastable phases, for various applications in electronics, optoelectronics, catalysis, biomedicine, energy storage and conversion, and ferroelectrics. Considering the significant progress in the synthesis and applications of TMDs, we believe that a comprehensive review on the phase engineering of TMDs is critical to promote their fundamental studies and practical applications. This Review aims to provide a comprehensive introduction and discussion on the crystal structures, synthetic strategies, and phase-dependent properties and applications of TMDs. Finally, our perspectives on the challenges and opportunities in phase engineering of TMDs will also be discussed. [ABSTRACT FROM AUTHOR]

Large dark current at room temperature has long been the major bottleneck that impedes the development of high‐performance infrared photodetectors toward miniaturization and integration. Although infrared photodetectors based on layered 2D narrow bandgap semiconductors have shown admirable advantages compared with those based on conventional compounds, which typically suffer from the expensive cryogenic operation, it is still urgent to develop a simple but effective strategy to further reduce the dark current. Herein, a tellurium (Te)‐based infrared photodetector is reported with specifically designed asymmetric electrical contact area. The deliberately introduced asymmetric electrical contact raises the electric field intensity difference in the Te channel near the drain and the source electrodes, resulting in the spontaneous asymmetric carrier diffusion under global infrared light illumination under zero bias. Specifically, the Te‐based photodetector presents promising detector performance at room temperature including a low dark current of ≈1 nA, an ultrahigh photocurrent/dark current ratio of 1.57 × 104, a high specific detectivity (D*) of 3.24 × 109 Jones, and a relatively fast response speed of ≈720 µs at zero bias. The results prove that the simple design of asymmetric electrical contact areas can provide a promising solution to high‐performance 2D semiconductor‐based infrared photodetectors working at room temperature. [ABSTRACT FROM AUTHOR]

• Slip bands initiated inside martensitic laths, are oriented parallel to the lath. • Internal slip bands of the martensitic laths cause cracks to initiate. • Crack are more likely to propagation along the martensitic laths. • The complex structure of martensite has a greater resistance to small crack growth. Martensitic steel presents high fatigue crack resistance due to its complex and hierarchical microstructure, but its mechanisms are unclear. This work experimentally investigated effect of the lath and the prior austenitic grain (PAGs) on crack initiation and the early propagation behavior in high cycle fatigue. It is found that micro cracks initiated from the slip bands in the interior of thin monocrystalline laths, in which the dislocation intensity zones deflected the crack path. Subsequently, the micro cracks coalesced through the lath boundaries, and resulted in an intermittent and staggered appearance of crack path in the PAGs. Finally, the crack propagation across the boundaries of the primary PAG are extremely slow and presents significant zigzag manners due to the misorientation of the laths in neighboring PAGs. The above observations demonstrate that the crack initiation and early propagation are significantly hindered by the multi-scaled microstructure of the martensitic steel. [ABSTRACT FROM AUTHOR]

In this work, light-induced degradation (LID) experiments were performed on p-type boron-doped Czochralski silicon (Cz-Si) wafers under different conditions, aiming to separately characterize boron-oxygen related LID (BO-LID) and "light and elevated temperature-induced degradation" (LeTID). We found that the regeneration rate of BO-LID, as well as the extent and kinetics of LeTID, were strongly influenced by peak firing temperature. These dependences can be explained by the variation of hydrogen concentration, which was modulated by peak firing temperature. Furthermore, we found that extending the duration of dark annealing pre-treatment decelerates the subsequent regeneration of BO defects. This result revealed that, under dark annealing, the evolution of LeTID was accompanied by a notable decrease in the mobile hydrogen concentration. Supported by this phenomenon, a hydrogen-related model based on reversible reaction is proposed to describe the LeTID behavior in crystalline silicon. • The change of firing temperature impact both BO-LID and LeTID behaviors. • Mobile hydrogen concentration decreases during the evolution of LeTID. • A novel hydrogen-related model based on a reversible reaction is proposed to explain LeTID mechanism. [ABSTRACT FROM AUTHOR]

Background: Tumor-associated macrophages (TAM)s are critical regulators of glioma progression. As yet, however, TAMs in isocitrate dehydrogenase (IDH) mutated lower-grade gliomas (LGGs) have not been thoroughly investigated. The aim of this study was to determine whether 1p/19q co-deletion status affects the TAM phenotype or its prevalence in IDH mutated LGGs. Methods: TAMs in IDH mutated LGGs were analyzed using transcriptome data from 230 samples in the TCGA database in combination with transcriptome data from single-cell RNA sequencing of IDH-mutated LGGs. Proteins potentially involved in TAM regulation were examined by immuno-staining in primary LGG samples harboring IDH mutations. Essential signaling pathways regulating TAM phenotypes were investigated in a glioma mouse model using small molecule inhibitors. Results: Most of the TAMs in IDH-mutated LGGs expressed the M1 activation markers CD86 and TNF, whereas a subset of individual TAMs co-expressed both M1 and M2-related markers. Bioinformatics analysis in combination with immuno-staining of IDH-mutated patient samples revealed higher amounts of TAMs expressing M2-related markers in 1p/19q non-codeletion IDH-mutated LGGs compared to 1p/19q codeletion LGGs. The levels of transforming growth factor beta 1 (TGFβ1) and macrophage colony-stimulating factor (M-CSF) were significantly higher in 1p/19q non-codeletion LGGs than in 1p/19q codeletion LGGs. M-CSF and TGFβ1 signal inhibition decreased tumor growth and modulated the TAM phenotype in a glioma mouse model. Conclusions: Our data indicate that 1p/19q co-deletion status relates to distinct TAM infiltration in gliomas, which is likely mediated by M-CSF and TGFβ1 signaling. M-CSF and TGFβ1 signaling may play a pivotal role in regulating the TAM phenotype in glioma. [ABSTRACT FROM AUTHOR]

A fundamental understanding of the charge transport mechanism in two-dimensional semiconductors (e.g., MoS 2) is crucial for fully exploring their potential in electronic and optoelectronic devices. By using monolayer graphene as the barrier-free contact to MoS 2 , we show that the field-modulated conductivity can be used to probe the electronic structure of the localized states. A series of regularly distributed plateaus were observed in the gate-dependent transfer curves. Calculations based on the variable-range hopping theory indicate that such plateaus can be attributed to the discrete localized states near mobility edge. This method provides an effective approach to directly profiling the localized states in conduction channel with an ultrahigh resolution up to 1 meV. [ABSTRACT FROM AUTHOR]

Subsurface cracking is a common feature at N > 107 cycles [i.e., in very high cycle fatigue (VHCF) regime]. Widely reported literatures focus mainly on the subsurface cracking at inclusions. However, it can initiate at the inner matrix as well, and the physic origin remains unclear. Here, we systematically explore the subsurface cracking at the inner matrix from mesoscale to atomic-scale. The results show that the subsurface cracking initiates from a single coarse lath, and dislocation tangles and cells generate at the extremely localized plastic deformation zones in proximity to the nanoprecipitates being of α-Fe. We suggest that the dislocations with high dense are blocked at the nanoprecipitate/α-Fe interfaces resulting in the nucleation of interfacial microcracks, which then coalesce into a trans-granular crack along the sub-boundaries covered by nanoprecipitates, finally the crack initiates within the coarse lath. These findings provide fundamental insights into the mechanism of precipitation-strengthening in anti-fatigue designs. [Display omitted] [ABSTRACT FROM AUTHOR]

• Deep convolution domain-adversarial transfer learning (DCDATL) is proposed. • Deep convolution residual feature extractor is constructed in DCDATL. • Domain-adversarial training between auxiliary domain and target domain is carried out in DCDATL. • Joint distribution domain-adversarial total loss function of DCDATL is minimized. • A fault diagnosis method based on DCDATL for rolling bearings is proposed. It is generally difficult to obtain a large number of labeled samples (i.e., samples with known fault types) of rolling bearings installed on large-scale mechanical equipment under current working conditions, which leads to the low accuracy of fault diagnosis for current testing samples using traditional machine learning algorithms. On account of this, a novel transfer learning method termed as deep convolution domain-adversarial transfer learning (DCDATL) is proposed for rolling bearing fault diagnosis in this paper. In the proposed DCDATL, a new deep convolution residual feature extractor is constructed to extract high-level features, which can avoid gradient problems such as gradient disappearance and gradient divergence during training DCDATL, thus improving the convergence and non-linear approximation ability of DCDATL. At the same time, the joint distribution of labeled samples in auxiliary domain and unlabeled samples in target domain is creatively used for domain-adversarial training, which can enhance the adaptability of samples in auxiliary domain to target domain and improve the transfer performance of DCDATL. Moreover, the strategy based on minimizing the joint distribution domain-adversarial total loss function of DCDATL is innovatively presented to improve the fault classification accuracy after high-level feature transfer. The above advantages of DCDATL make it feasible to perform high-precision fault diagnosis on current testing samples by using the historical labeled samples in auxiliary domain when there are no labeled samples in target domain. The fault diagnosis examples of rolling bearings demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Platinum (Pt) is a state-of-the-art electrocatalyst for green hydrogen production in alkaline electrolytes. The delicate design and fabrication of two-dimensional (2D) Pt nanocatalysts can significantly enhance atomic utilization efficiency, while further improving intrinsic catalytic performance by modulating the density of surface active sites. However, the high surface energy and morphology complexity of 2D nanostructures often result in poor structural stability under the working conditions. Here, we report the synthesis of a 2D ring-on-sheet nanoheterostructure featuring abundant low-coordination Pt sites in which a defect-rich Pt nanoring is stabilized by an ultrathin 2D rhodium (Rh) support. The Rh@Pt nanoring exhibits remarkably enhanced activity and stability in an electrocatalytic hydrogen evolution reaction in alkaline media compared to defect-free Rh@Pt core-shell nanoplates and commercial Pt/C. This work provides new insights for the design and synthesis of 2D nanoheterostructures with abundant surface active sites for efficient and durable electrocatalysis.

Molybdenum diphosphide (MoP 2 ), a topological semimetal, possesses distinctive properties and applications in catalysis, energy storage, and condensed matter physics. However, synthesizing high-purity MoP 2 is complex and often results in undesired stoichiometric by-products. Additionally, the intrinsic orthorhombic crystal structure makes it difficult to synthesize MoP 2 in a 2D morphology, which is desirable for device and energy applications. Here, the robust synthesis of MoP 2 with a well-defined 2D morphology is achieved using the confined gas-solid phosphorization of a MoS 2 precursor on substrates. The use of 2D precursors and the surface confinement provided by the substrate maintain the 2D morphology and result in a thickness-dependent stoichiometry of the phosphorization products. The chemical composition and crystal structure of MoP 2 nanosheets are comprehensively characterized. At room temperature, MoP 2 nanosheets exhibit metallic transport with high conductivity over 5500 S cm -1 . Furthermore, MoP 2 nanosheets demonstrate excellent electrocatalytic activity and durability for hydrogen evolution in both neutral and acid mediums. Notably, MoP 2 nanosheets possess better durability than amorphous Pt film and commercial Pt/C, positioning MoP 2 as a promising catalyst for hydrogen evolution in neutral mediums. This work advances the synthetic chemistry of 2D MoP 2 and provides 2D semimetals with a novel member for future explorations in diverse fields., (© 2024 Wiley‐VCH GmbH.)

Heme oxygenase-1 (HO-1) catalyzes heme degradation on the consumption of NADPH and molecular oxygen. As an inducible enzyme, HO-1 is highly induced in various disease states, including cancer. Currently, two fluorescent probes for HO-1 have been designed based on the catalytic activity of HO-1, in which the probes serve as a substrate, so NADPH is required to enable the detection. Probes functioning in a NADPH-dependent way may influence other NADPH-consuming pathways, as all these pathways share a common NADPH pool. Here, we report the peptide-based fluorescent probe NBD-P 5 as a simple alternative approach for HO-1 sensing. The designed probe NBD-P 5 functions independently of the catalytic activity of HO-1, therefore enabling fast and sensitive detection of HO-1 with no requirements of other substances, including NADPH and biliverdin reductase. Moreover, it overcomes the need for a large substrate amount and long incubation time during the detection. NBD-P 5 can be quickly taken up by cells, demonstrates an excellent colocalization with the endoplasmic reticulum (where HO-1 is mainly located), and is shown to be reliable in reporting changes in HO-1 levels in live cells. This work provides a simple alternative approach for designing HO-1 fluorescent probes, and we expect it will act as a practical tool for further studying HO-1 biology.

The hybrid integration of two-dimensional (2D) materials on various photonic integration platforms has attracted widespread research interest because of the new functionalities enabled by the 2D materials for applications in photodetection, optical modulation and nonlinear optical signal processing. Tellurium is known to have high mobility, and quasi-2D tellurium is stable in air and has a small bandgap that may make it suitable for platform-independent scalable integration of high-performance photodetectors in the infrared band. In this work, we propose and implement a new structure for integrating tellurium with silicon nitride (SiN) waveguides, adding photodetector capability to an otherwise passive waveguide platform. At a wavelength of 1570 nm, the fabricated tellurium photodetector has an experimentally measured responsivity of 0.5 A W -1 at 1 V bias voltage and a bandwidth of 12 GHz. We show that the bandwidth is not limited by the carrier transit time, but rather by the RC time constant, which can be further improved.

Self-assembly processes commonly occur in various biological contexts to form functional biological structures. However, the self-assembly of nanofibers within cells by heterologous molecules showing a biological function is rare. In this work, we reported the intracellular formation of fluorescent nanofibers by a natural small molecule, lycobetaine (LBT), which facilitated the direct physical connection between mitochondria and synchronized their membrane potential oscillations. The luminescent properties of LBT enabled the real-time observation of nanofiber formation, while the semiconductive nature of the LBT nanofiber facilitated electrical signal transduction among the connected mitochondria. This study introduces an approach to modulate mitochondrial connectivity within cells using "nano-cables" which facilitate studies on synchronized mitochondrial operations and the underlying mechanisms of drug action.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) with layered crystal structures have been attracting enormous research interest for their atomic thickness, mechanical flexibility, and excellent electronic/optoelectronic properties for applications in diverse technological areas. Solution-processable 2D TMD inks are promising for large-scale production of functional thin films at an affordable cost, using high-throughput solution-based processing techniques such as printing and roll-to-roll fabrications. This paper provides a comprehensive review of the chemical synthesis of solution-processable and printable 2D TMD ink materials and the subsequent assembly into thin films for diverse applications. We start with the chemical principles and protocols of various synthesis methods for 2D TMD nanosheet crystals in the solution phase. The solution-based techniques for depositing ink materials into solid-state thin films are discussed. Then, we review the applications of these solution-processable thin films in diverse technological areas including electronics, optoelectronics, and others. To conclude, a summary of the key scientific/technical challenges and future research opportunities of solution-processable TMD inks is provided.

Herein, we present the discovery and development of the first photoredox-catalyzed alkoxy diazomethylation of alkenes with hypervalent iodine reagents and alcohols. This multicomponent process represents a new disconnection approach to diazo compounds and is featured by a broad scope, mild reaction conditions, and excellent selectivity. Key to the process was the generation of diazomethyl radicals, which engaged alkenes and alcohols in an inter- and intramolecular fashion by a photoredox-catalyzed oxidative radical-polar crossover leading to unexplored β-alkoxydiazo compounds. The synthetic utility of such diazo compounds was demonstrated with a series of transformations involving C-H, N-H, and O-H insertions as well as in the construction of complex sp 3 -rich heterocycles.

Elemental 2D materials (E2DMs) have been attracting considerable attention owing to their chemical simplicity and excellent/exotic properties. However, the lack of robust chemical synthetic methods seriously limits their potential. Here, a surfactant-free liquid-phase synthesis of high-quality 2D tellurium is reported based on ultrasonication-assisted exfoliation of metastable 1T'-MoTe 2 . The as-grown 2D tellurium nanosheets exhibit excellent single crystallinity, ideal 2D morphology, surfactant-free surface, and negligible 1D by-products. Furthermore, a unique growth mechanism based on the atomic escape of Te atoms from metastable transition metal dichalcogenides and guided 2D growth in the liquid phase is proposed and verified. 2D tellurium-based field-effect transistors show ultrahigh hole mobility exceeding 1000 cm 2  V -1  s -1 at room temperature attributing to the high crystallinity and surfactant-free surface, and exceptional chemical and operational stability using both solid-state dielectric and liquid-state electrical double layer. The facile ultrasonication-assisted synthesis of high-quality 2D tellurium paves the way for further exploration of E2DMs and expands the scope of liquid-phase exfoliation (LPE) methodology toward the controlled wet-chemical synthesis of functional nanomaterials., (© 2023 Wiley‐VCH GmbH.)

As a key structural parameter, phase depicts the arrangement of atoms in materials. Normally, a nanomaterial exists in its thermodynamically stable crystal phase. With the development of nanotechnology, nanomaterials with unconventional crystal phases, which rarely exist in their bulk counterparts, or amorphous phase have been prepared using carefully controlled reaction conditions. Together these methods are beginning to enable phase engineering of nanomaterials (PEN), i.e. , the synthesis of nanomaterials with unconventional phases and the transformation between different phases, to obtain desired properties and functions. This Review summarizes the research progress in the field of PEN. First, we present representative strategies for the direct synthesis of unconventional phases and modulation of phase transformation in diverse kinds of nanomaterials. We cover the synthesis of nanomaterials ranging from metal nanostructures such as Au, Ag, Cu, Pd, and Ru, and their alloys; metal oxides, borides, and carbides; to transition metal dichalcogenides (TMDs) and 2D layered materials. We review synthesis and growth methods ranging from wet-chemical reduction and seed-mediated epitaxial growth to chemical vapor deposition (CVD), high pressure phase transformation, and electron and ion-beam irradiation. After that, we summarize the significant influence of phase on the various properties of unconventional-phase nanomaterials. We also discuss the potential applications of the developed unconventional-phase nanomaterials in different areas including catalysis, electrochemical energy storage (batteries and supercapacitors), solar cells, optoelectronics, and sensing. Finally, we discuss existing challenges and future research directions in PEN.