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The formation of 1D molecular wires of ClAlPc due to the substrate symmetry breaking of graphene induced by the presence of quasi-1D moiré patterns.

A NO2/SbP adsorption system with high adsorption energy (−0.876 eV) and charge transfer value (−0.83 e) is reported.

In this work, we predict two novel two-dimensional (2D) auxetic materials, BiSbX3 (X = S, Se) monolayers, through first-principles calculations. Attributed to their special braceletlike structure, the in-plane negative Poisson's ratio (NPR) of BiSbS3 and BiSbSe3 monolayers are as high as -0.25 and -0.26, respectively. The phonon dispersion calculations, ab initio molecular dynamics simulations, and elastic constants calculations demonstrate that these two monolayers possess excellent dynamic, thermal, and mechanical stabilities. The band gap values of BiSbS3 and BiSbSe3 calculated at the HSE level by considering the spin-orbit coupling (SOC) effect are 1.68 and 1.20 eV. The anisotropic carrier mobility and superior optical absorption indicate that they may shine in the next generation of electronic and optoelectronic devices. All of these discoveries not only enrich the types of auxetic materials but also provide a structural reference for designing new auxetic materials on the molecular level. Furthermore, they can provide theoretical guidance for future applications of BiSbX3 (X = S, Se) monolayers in various fields.

Aroused by plant photosynthesis, Z-scheme heterostructures have been considered as a potential photocatalyst for solar-driven water splitting to solve the current energy crisis. Hence, based on first-principles calculations, we predict that Sc2CF2/Janus MoSSe can be used as a Z-scheme heterostructure for efficient photocatalytic water splitting. The research shows that the traditional type-II to direct Z-scheme heterostructure conversion can be realized through different stacking methods of Sc2CF2 and Janus MoSSe. Through the built-in electric field and band bending theory, the transition path of photogenerated carriers is analyzed, which reveals the completely different photocatalytic mechanism of type-II and direct Z-scheme heterostructure. Surprisingly, the direct Z-scheme heterostructure displays a high overpotential of the hydrogen evolution reaction ( χ H 2 =1.01 eV) and the oxygen evolution reaction ( χ O 2 =1.46 eV) compared with the type II heterostructure. More importantly, the direct Z-scheme heterostructure has an ultra-high solar-to-hydrogen (STH) efficiency (36.1%), which breaks through the limitation of traditional theoretical efficiency and reveals a tremendous prospect of commercial application. Furthermore, the calculation of free energy confirms that the water splitting reaction on the direct Z-scheme heterostructure occur spontaneously under the external potential, but not for type-II heterostructure. Finally, introducing the additional electronic conductor (N-doped graphene) can accelerate the electron (hole) transfer and interlayer carrier recombination, which will further improve the photocatalytic performance of Z-scheme heterostructure. These distinctive features make Sc2CF2/Janus MoSSe heterostructure as promising Z-scheme photocatalyst for water splitting.

In-plane heterostructures of graphene and hexagonal boron nitride (h-BN) exhibit exceptional properties, which are highly sensitive to the structure of the alternating domains. Nevertheless, achieving accurate control over their structural properties, while keeping a high perfection at the graphene-h-BN boundaries, still remains a challenge. Here, the growth of lateral heterostructures of graphene and h-BN on Rh(110) surfaces is reported. The choice of the 2D material, grown firstly, determines the structural properties of the whole heterostructure layer, allowing to have control over the rotational order of the domains. The atomic-scale observation of the boundaries demonstrates a perfect lateral matching. In-plane heterostructures floating over an oxygen layer have been successfully obtained, enabling to observe intervalley scattering processes in graphene regions. The high tuning capabilities of these heterostructures, along with their good structural quality, even around the boundaries, suggest their usage as test beds for fundamental studies aiming at the development of novel nanomaterials with tailored properties., Financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) and Fondo Europeo de Desarrollo Regional (FEDER) under grant No. MAT2016-77852-C2-2-R, as well as, from the Spanish Ministerio de Ciencia e Innovación through the “María de Maetzu” program for units of excellence in R&D (grant No. CEX2018-000805-M) was gratefully acknowledged. A. J. M.-G. acknowledged funding by the Spanish Ministerio de Ciencia e Innovación (MICINN through Project No. PID2020-116619GA-C22, as well as, by the Comunidad de Madrid and Universidad Autónoma de Madrid under Project No. SI3/PJI/2021-00500. Funding sources: Spanish MINECO (Ref: MAT2016-77852-C2-2-R). Spanish MICINN (Ref: PID2020-116619GA-C22). Comunidad de Madrid (CAM) and Universidad Autónoma de Madrid (UAM) (Ref: SI3/PJI/2021-00500)

The gas-sensing performance of PbSnS2 monolayer to sulfur hexafluoride (SF6) decompositions (SO2, H2S, HF, SOF2, and SO2F2) has been systematically studied by density functional theory and nonequilibrium Green’s function calculations. The most stable adsorption configurations, adsorption energies, charge transfer, electron localization function (ELF), density of states (DOS), and ${I}$ – ${V}$ curves of gas molecules on PbSnS2 are calculated and discussed. SO2 exhibits the largest adsorption energy of −0.74 eV with the charge transfer of −0.39 e and HF possesses the biggest charge transfer of −0.66 e with the adsorption energy of −0.46 eV. The results of ELF and DOS show that the interaction between SO2 and PbSnS2 may be stronger than those of other gases. Moreover, ${I}$ – ${V}$ curves show that the responses of PbSnS2 to SO2 is up to 65.5% at the bias of 2.2 V. Therefore, PbSnS2 monolayer may be a qualified material for detecting SF6 decompositions.

In this work, we explore the application potential of AsP/M2CO2 (M = Sc, Zr) van der Waals heterostructures in photocatalytic water splitting through the first-principles calculations. The calculated results show that AsP/Zr2CO2 heterostructure possesses an unfavorable type-Ⅰ band alignment, whereas AsP/Sc2CO2 exhibits a desirable type-Ⅱ band alignment, which is beneficial for separating the photogenerated electron-hole pairs. Also, the band edge positions of AsP/Sc2CO2 heterostructure stride the redox potential of water, ensuring favorable reaction kinetics. Besides, the strong optical absorption of AsP/Sc2CO2 heterostructure in both visible and ultraviolet regions (especially up to 10−6 cm−1 at about 250 nm) makes it possible to utilize solar energy effectively. Meanwhile, AsP/Sc2CO2 heterostructure has an exciton binding energy as low as 0.09 eV, which quantitatively illustrates the high separation efficiency of photogenerated charge carrier. Thus, the type-Ⅱ band alignment, suitable band edge position, strong light absorption, and low exciton binding energy together indicate that AsP/Sc2CO2 heterostructure is a potential photocatalytic material. In addition, the obvious redshift phenomenon in the optical spectrum of AsP/Sc2CO2 heterostructure shows that biaxial strain can improve its light capture capability. Also, the interconversion between type-Ⅱ and type-Ⅰ can be achieved by applying different strains. All these findings suggest that the novel AsP/Sc2CO2 heterostructure has significant application prospects in next-generation photovoltaic and photocatalytic devices.

In certain unconventional superconductors with sizable electronic correlations, the availability of closely competing pairing channels leads to characteristic soft collective fluctuations of the order parameters, which leave fingerprints in many observables and allow the phase competition to be scrutinized. Superconducting layered materials, where electron-electron interactions are enhanced with decreasing thickness, are promising candidates to display these correlation effects. In this work, the existence of a soft collective mode in single-layer NbSe

The chemical modulation associated with moiré patterns, arising at the interface of metal-supported 2D material systems, affects the interaction between molecules and 2D materials on surfaces. Since the crystallography of the support influences the interfacial chemistry of the moiré modulation, this parameter could also play a role in the graphene-molecule interaction, although studies using non-hexagonal metal supports are needed to investigate this effect. It is a key issue since graphene appears combined with organic films in most technological advances related to this material. Here, we have characterized the properties of PTCDA molecules on graphene grown on Rh(110) substrates, which exhibit a rectangular atomic packing, using scanning tunneling microscopy and spectroscopy. The results showed that PTCDA molecules are arranged on the surface into a herringbone structure exhibiting a long-range ordering, which grows continuously across substrate atomic steps edge and dislocations. The quasi-1D moiré patterns of the Gr/Rh(110) surfaces are found to provide an inert chemical landscape for the molecular arrangement. Bias voltage-dependent imaging of the orbital structure of PTCDA molecules and differential conductance spectra back up a weak molecule–substrate interaction scheme. Finally, the α-polymorph of bulk crystal PTCDA has been determined as the favored stacking configuration for bilayer molecules on Gr/Rh(110), Financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) and Fondo Europeo de Desarrollo Regional (FEDER) under grant No. MAT2016-77852-C2-2-R, as well as, from the Spanish Ministerio de Ciencia e Innovacion ´ (MICINN) through the “María de Maetzu” program for units of excellence in R&D (grant No. CEX2018-000805-M) is gratefully acknowledged. A. J. M.-G. acknowledges funding by the Spanish Ministerio de Ciencia e Innovacion ´ (MICINN) through Project No. PID2020-116619GA-C22, as well as, from the Comunidad de Madrid and the Universidad Autonoma ´ de Madrid under project SI3/PJI/2021- 00500

It is found that many two-dimensional materials are easy to obtain out-of-plane piezoelectric properties because of their Janus structure. Here, based on the monolayer GeSe and SnSe, we study the electronic structure and piezoelectricity of the Janus M2SeX (M=Ge, Sn; X=S, Te) monolayers. Due to the lack of inversion symmetry and mirror symmetry, as well as flexible mechanical properties, the 2D Janus M2SeX monolayers have large in-plane piezoelectric coefficients d11 (up to 345.08pm/V) and out-of-plane piezoelectric coefficients d31 (up to 3.83pm/V). All energy band structures of two-dimensional (2D) Janus M2SeX monolayers show indirect bandgap and Zeeman-type spin splitting after considering spin orbit coupling (SOC). The lack of mirror symmetry leads to out-of-plane spin polarization. In addition, the calculation based on the deformation potential theory shows that the 2D Janus M2SeX monolayers have high carrier mobility. The large piezoelectric properties and high carrier mobility show the application potential of 2D Janus M2SeX monolayers in flexible electronic devices and piezoelectric devices.

The increasingly wide application of chloroplast (cp) genome super‐barcode in taxonomy and the recent breakthrough in cp genetic engineering make the development of new cp gene resources urgent and significant. Corydalis is recognized as the most genotypes complicated and taxonomically challenging plant taxa in Papaveraceae. However, there currently are few reports about cp genomes of the genus Corydalis. In this study, we sequenced four complete cp genomes of two endangered lithophytes Corydalis saxicola and Corydalis tomentella in Corydalis, conducted a comparison of these cp genomes among each other as well as with others of Papaveraceae. The cp genomes have a large genome size of 189,029–190,247 bp, possessing a quadripartite structure and with two highly expanded inverted repeat (IR) regions (length: 41,955–42,350 bp). Comparison between the cp genomes of C. tomentella, C. saxicola, and Papaveraceae species, five NADH dehydrogenase‐like genes (ndhF, ndhD, ndhL, ndhG, and ndhE) with psaC, rpl32, ccsA, and trnL‐UAG normally located in the SSC region have migrated to IRs, resulting in IR expansion and gene duplication. An up to 9 kb inversion involving five genes (rpl23, ycf2, ycf15, trnI‐CAU, and trnL‐CAA) was found within IR regions. The accD gene was found to be absent and the ycf1 gene has shifted from the IR/SSC border to the SSC region as a single copy. Phylogenetic analysis based on the sequences of common CDS showed that the genus Corydalis is quite distantly related to the other genera of Papaveraceae, it provided a new clue for recent advocacy to establish a separate Fumariaceae family. Our results revealed one special cp genome structure in Papaveraceae, provided a useful resources for classification of the genus Corydalis, and will be valuable for understanding Papaveraceae evolutionary relationships., Our results revealed one special cp genome structure in Papaveraceae, provided a useful resources for classification of the genus Corydalis, and will be valuable for understanding Papaveraceae evolutionary relationships.

A subsecond and novel approach of electroshock treatment (EST) is used in this study to repair defects in directed-energy-deposited Ti-5Al-5Mo-5V-3Cr-1Zr near-β titanium alloy. After EST, the porosity of the specimen decreased significantly from 0.81 to 0.1 pct. Large cracks observed at the bottom of the above mentioned near-β titanium alloy became intermittent small cracks and the number of voids decreased. The defects in the top and middle regions of the specimens are repaired. The potential defect repair is attributable to energy concentration, which promoted the coalescence of defect tips, and thermal stresses, which compressed the defects inward and closed them.

In this study, the adsorption of gas molecules, such as O2, NH3, CO, CO2, H2O, NOx (x = 1, 2) and SO2, on Janus Te2Se monolayer has been investigated by means of density functional theory (DFT) calculations. We show that Janus Te2Se monolayer is preferable for SO2 and NOx molecules with suitable adsorption strength and apparent charge transfers. We further calculated the current-voltage (I-V) curves using the nonequilibrium Green's function (NEGF) method. The transport feature exhibits distinct responses with a dramatic change of I-V curves before and after NOx (SO2) adsorption on Janus Te2Se. Thus, we predict that Janus Te2Se could be a promising candidate for SO2 and NOx sensors with high selectivity and sensitivity. Moreover, the effect of strain on the gas/substrate adsorption systems was also studied, implying that the strained Janus Te2Se monolayer could enhance the sensitivity and selectivity to SO2 and NO2. The adsorbed SO2 and NO2 on Janus Te2Se could escape by releasing the applied strain, which indicates that the capture process is reversible. Our study widens the application of Janus Te2Se not only as piezoelectric materials, but also as a potential gas sensor or capturer of SO2 and NOx with high sensitivity and selectivity.

Two-dimensional Janus nanomaterials, due to their unique electronic, optical, and piezoelectric characteristics resulting from the antisymmetric structures, exhibit great prospects in multifunctional energy application to alleviate the energy crisis. Monolayer Janus Pb2SSe, with a black phosphorus-like structure and an indirect band gap of 1.59 eV as well as high carrier mobility (526-2105 cm2 V-1 s-1), displays outstanding potentials in the energy conversion between nanomechanical energy, solar energy, waste heat, and electricity, which has been comprehensively studied utilizing DFT-based simulations. The research results reveal that monolayer Pb2SSe not only possesses giant in-plane piezoelectricity of d11 = 75.1 pm V-1 but also superhigh out-of-plane piezoelectric coefficients (d31 = 0.5 pm V-1 and d33 = 15.7 pm V-1). Meanwhile, by constructing Pb2SSe bilayers, the out-of-plane piezoelectric coefficients can be significantly enhanced (d31 = 19.2 pm V-1 and d33 = 194.7 pm V-1). In addition, owing to the small conduction band offset, suitable donor band gap and excellent light absorption capability in the Pb2SSe/SnSe (Pb2SSe/GeSe) heterostructure, the power conversion efficiencies were calculated to be up to 20.02% (Pb2SSe/SnSe) and 19.28% (Pb2SSe/GeSe), making it a promising candidate for solar energy collection. Furthermore, from the thermoelectric electron and phonon transport calculations, it can be found that the Pb2SSe monolayer is an n-type thermoelectric material with ultrahigh ZT = 2.19 (1.52) at room temperature, which can be traced back to its ultralow κL = 0.78 (0.99) W m-1 K-1, and superhigh PF = 10.18 (8.25) mW m-1 K-2 along the x(y) direction at the optimal doping concentration at 300 K. The abovementioned versatile characteristics in the Janus Pb2SSe monolayer, along with its comprehensive stabilities (energy, dynamic, thermal, and mechanical stabilities), highlight its potential in clean energy harvesting.

Objective Schisandra sphenanthera and S. chinensis are the two important medicinal plants that have long been used under the names of “Nan-Wuweizi” and “Wuweizi”, respectively. The misuse of “Nan-Wuweizi” and “Wuweizi” in herbal medical products calls for an accurate method to distinguish these herbs. Chloroplast (cp) genomes have been widely used in species delimitation and phylogeny due to their uniparental inheritance and lower substitution rates than that of the nuclear genomes. To develop more efficient DNA markers for distinguishing S. sphenanthera, S. chinensis, and the related species, we sequenced the cp genome of S. sphenanthera and compared it to that of S. chinensis. Methods The cp genome of S. sphenanthera was sequenced at the Illumina HiSeq platform, and the reference-guided mapping of contigs was obtained with a de novo assembly procedure. Then, comparative analyses of the cp genomes of S. sphenanthera and S. chinensis were carried out. Results The cp genome of S. sphenanthera was 146 853 bp in length and consisted of a large single copy (LSC) region of 95 627 bp, a small single copy (SSC) region of 18 292 bp, and a pair of inverted repeats (IR) of 16 467 bp. GC content was 39.6%. A total of 126 functional genes were predicted, of which 113 genes were unique, including 79 protein-coding genes, 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. Five tRNA, four protein-coding genes, and all rRNA were duplicated in the IR regions. There were 18 intron-containing genes, including six tRNA genes and 12 protein-coding genes. In addition, 45 SSRs were detected. The whole cp genome of S. sphenanthera was 123 bp longer than that of S. chinensis. A total of 474 SNPs and 97 InDels were identified. Five genetic regions with high levels of variation (Pi > 0.015), trnS-trnG, ccsA-ndhD, psbI-trnS, trnT-psbD and ndhF-rpl32 were revealed. Conclusion We reported the cp genome of S. sphenanthera and revealed the SNPs and InDels between the cp genomes of S. sphenanthera and S. chinensis. This study shed light on the species identification and further phylogenetic study within the genus of Schisandra.

Electro-shocking treatment (EST) has been investigated as a pathway to optimise the microstructure and mechanical properties of titanium alloys. The thermal conditions introduced by EST resulted in a phase transformation from α to β. The fraction of β phase decreased from 25.27% to 19.47% after EST for 0.02 s, which was possibly caused by the recrystallization of α phase. The application of EST for 0.04 s resulted in an increase in volume fraction of the β phase to 26.95%. The energy introduced by EST resulted in changes to the direction and intensity of texture within the microstructure with the texture intensity of the α phase increasing from 4.94 to 8.52, and that of β both increased from 3.35 to 9.88 after 0.04 s EST. Keywords: Electroshocking treatment (EST), Microstructure, Phase transformation, Phase content, Texture, TC11 alloy

This work investigates a novel pulsating DC high-voltage linear driving scheme for GaN-based Light-emitting diode (GaN LED) general lighting to save costs and alleviate flicker. The superiority and practicality of this scheme in three-phase AC power grids were demonstrated for the first time. Compared to applications for single-phase AC grids, linear driving of GaN LEDs for three-phase AC grids can provide superior performance for general lighting. The DC component of the three-phase AC rectified voltage reaches 90.7%, which effectively alleviates the flicker problem. In this paper, we balanced GaN LED power and driving efficiency by optimizing the GaN LED distribution of the linear multi-string GaN LED driving scheme while taking the effects of grid voltage fluctuations into account. In addition, we constructed a double-string GaN LED lighting system as a modular prototype with scalability. The experimental results exhibit high driving efficiency (~94% @380 V line voltage), high power factor (~0.952), flicker-free, and high reliability at a very low cost (~$0.005/W).

Achieving superior performance of nanoparticle systems is one of the biggest challenges in catalysis. Two major phenomena, occurring during the reactions, hinder the development of the full potential of nanoparticle catalysts: sintering and contamination with carbon containing species, sometimes called coking. Here, we demonstrate that Ir nanocrystals, arranged into periodic networks on hexagonal boron nitride (h-BN) supports, can be restored without sintering after contamination by persistent carbon. This restoration yields the complete removal of carbon from the nanocrystals, which keep their crystalline structure, allowing operation without degradation. These findings, together with the possibility of fine tuning the nanocrystals size, confer this nanoparticle system a great potential as a testbed to extract key information about catalysis-mediated oxidation reactions. For the case of the CO oxidation by O2, reaction of interest in environmental science and green energy production, the existence of chemical processes not observed before in other nanoparticle systems is demonstrated, Open access funding provided thanks to the CRUE-CSIC agreement with Springer Nature

Effects of electroshock treatment (EST) on the microstructural evolution and mechanical properties of near-β titanium alloy (Ti-55531) formed by directed energy deposition (DED) was studied in this work. With the increase in EST time, the average hardness of specimen decreased from 426 HV to 316 HV, and the fracture strain increased significantly, which was attributed to the uniform dispersion of α phase along grain boundaries and inside the β grains. After EST, the texture intensity decreased in terms of the orientation distribution function (ODF), which was ascribed to the redistribution of α phase. Moreover, more atomic vacancies and lattice distortion were formed near the α/β interfaces, which were verified by transmission electron microscopy (TEM) observation and ascribed to the migration of atoms near the interface under EST. External loadings facilitated the dislocation motion and lattice distortions near the interfaces, which resulted in the reduction in hardness and the improvement in ductility. The above results indicated that EST can quickly alter the microstructure and mechanical properties of DED titanium alloys as a simple and energy-saving method.

Collective electronic states such as the charge density wave (CDW) order and superconductivity (SC) respond sensitively to external perturbations. Such sensitivity is dramatically enhanced in two dimensions (2D), where 2D materials hosting such electronic states are largely exposed to the environment. In this regard, the ineludible presence of supporting substrates triggers various proximity effects on 2D materials that may ultimately compromise the stability and properties of the electronic ground state. In this work, we investigate the impact of proximity effects on the CDW and superconducting states in single-layer (SL) NbSe2 on four substrates of diverse nature, namely, bilayer graphene (BLG), SL-boron nitride (h-BN), Au(111), and bulk WSe2. By combining low-temperature (340 mK) scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy, we compare the electronic structure of this prototypical 2D superconductor on each substrate. We find that, even when the electronic band structure of SL-NbSe2 remains largely unaffected by the substrate except when placed on Au(111), where a charge transfer occurs, both the CDW and SC show disparate behaviors. On the insulating h-BN/Ir(111) substrate and the metallic BLG/SiC(0001) substrate, both the 3 × 3 CDW and superconducting phases persist in SL-NbSe2 with very similar properties, which reveals the negligible impact of graphene on these electronic phases. In contrast, these collective electronic phases are severely weakened and even absent on the bulk insulating WSe2 substrate and the metallic single-crystal Au(111) substrate. Our results provide valuable insights into the fragile stability of such electronic ground states in 2D materials.

In this work, we predict two novel two-dimensional (2D) auxetic materials, BiSbX