Electronic Carriers Research Articles

Hydrogen production of overall water splitting with direct Z-scheme driven by antimonene and arsenide nanoribbon heterostructures: Insight from electronic properties and carrier nonadiabatic dynamics

Two nanoribbon heterostructures are suitable for driving efficient direct Z-schemes of the photocatalytic overall water splitting for hydrogen production and are screened out of nine heterostructures constructed from edge-passivated antimonene (SbNR-X) and arsenide (AsNR-X, X = F, Cl, CN) nanoribbons. The solar-to-hydrogen (STH) efficiency and the Gibbs free energies (ΔGs) of the redox reactions at different sites are calculated to identify the preferable Z-schemes. Meanwhile, the transfer and recombination of the photogenerated carriers are explored by using nonadiabatic molecular dynamics (NAMD) simulations. The obtained band alignments and built-in electric fields of the two considered heterostructures can match the requirements of the photocatalytic Z-scheme, and the corresponding STH efficiencies can reach 15.04 % and 30.53 %, respectively. The oxidation evolution reactions can proceed spontaneously, and hydrogen evolution reactions are feasible in thermodynamics. NAMD simulations show that the SbNR-CN/AsNR-CN nanoribbon heterostructure has faster interlayer recombination but slower transfer of the photogenerated electron from the SbNR-CN to AsNR-CN nanoribbons and of the photogenerated hole along the reversible direction, indicating that this heterostructure has a higher carrier utilization rate. These findings confirm that the SbNR-CN/AsNR-CN nanoribbon heterostructure is a promising candidate for developing high STH efficiency materials with direct Z-schemes.

Doping-mediated excited state dynamics of diphosphine-protected M@Au12 (M = Au, Ir) superatom nanoclusters.

Doping heterometal atoms into ligand-protected gold superatom nanoclusters (Aun NCs) is proposed to further diversify their geometrical and electronic structures and enhance their photoluminescence properties, which is attributed to the mixing and effects between atoms. However, the fundamental principles that govern the optoelectronic properties of the doped Aun NCs remain elusive. Herein, we systematically explored two prototypical 8-electron Aun (n = 11 and 13) NCs with and without Ir dopant atoms using comprehensive ab initio calculations and real-time nonadiabatic molecular dynamics simulations. These doped Aun NCs maintain their parent geometrical structures and 8-electron superatomic configuration (1S21P6). Strong core-shell (Ir-Aun) electronic coupling significantly expands the energy gap, resulting in a weak nonadiabatic coupling matrix element, which in turn increases the carrier lifetime. This increase is mainly governed by the low-frequency vibration mode. We uncovered the relationship between electronic structures, electron-vibration, and carrier dynamics for these doped Aun NCs. These calculated results provide crucial insights for the atomically precise design of metal NCs with superior optoelectronic properties.

Carrier transport in bulk and two-dimensional Zn2(V,Nb,Ta)N3 ternary nitrides.

Density functional theory-based simulations are applied to study the electronic structures, carrier masses, carrier mobility and carrier relaxation times in bulk and two-dimensional (2D) Zn2(V,Nb,Ta)N3 ternary nitrides. Bulk Zn2(V,Nb,Ta)N3 possess moderate band gap sizes of 2.17 eV, 3.11 eV, and 3.40 eV, respectively. Two-dimensional Zn2(V,Nb,Ta)N3 have slightly higher band gap sizes of 2.77 eV, 3.33 eV, and 3.23 eV, respectively. Carrier mass, carrier mobility and carrier relaxation time are found to be anisotropic in all the studied structures. Bulk and 2D samples show an order of magnitude higher electron mobility compared to hole mobility. The highest electron mobility in bulk Zn2NbN3 and Zn2TaN3 is about ∼103 cm2 V-1 s-1. Importantly, for 2D Zn2NbN3, an abnormally high electron mobility of 1.67 × 104 cm2 V-1 s-1 is observed, which is not inferior to the highest known electron mobility values in 2D materials. Such a high electron mobility in 2D Zn2NbN3 can be attributed to a strong delocalization of the conduction band minimum, which is responsible for electron transport. Therefore, this work opens up new materials for high performance nanodevices, such as tandem solar cells and field-effect transistors. This study also provides deep physical insights into the nature of carrier transport mechanisms in bulk and 2D Zn2(V,Nb,Ta)N3 ternary nitrides.

Revealing large room-temperature Nernst coefficients in 2D materials by first-principles modeling.

Two-dimensional (2D) materials have attracted significant attention owing to their distinctive electronic, thermal, and mechanical characteristics. Recent advancements in both theoretical understanding and experimental methods have greatly contributed to the understanding of thermoelectric properties in 2D materials. However, thermomagnetic properties of 2D materials have not yet received the same amount of attention. In this work, we select promising 2D materials guided by the physics of the Nernst effect and present a thorough first-principles study of their electronic structures, carrier mobilities, and Nernst coefficients as a function of carrier concentration. Specifically, we reveal that trilayer graphene with an ABA stacking exhibits an exceptionally large Nernst coefficient of 112 μV (KT)-1 at room temperature. We further demonstrate that monolayer graphene, ABC-stacked trilayer graphene, and trilayer phosphorene (AAA stacking) have large Nernst coefficients at room temperature. This study establishes an ab initio framework for the quantitative study of the thermomagnetic effects in 2D materials and demonstrates high fidelity with previous experimental data.

Organic cations in halide perovskite solid solutions: exploring beyond size effects.

Halide perovskites are a class of materials of consolidated optoelectronic and electrochemical applications, reaching efficiencies compared to established materials in respective fields. In this scenario, the design and understanding of composition-structure-property relations is imperative. In solid solutions containing mixed cations, some direct relations between the sizes of the substituents and the properties of perovskites are generally observed. However, in several cases, these relations are not observed, implying that other characteristics of these cations play a major role. Despite its importance, this understanding has not been comprehensively deepened. To address this issue, we synthesized and characterized the structure, electrical behavior, and stability of methylammonium lead iodide-based perovskites with equal amounts of the substituents guanidinium, ethylammonium, and acetamidinium. These three large organic cations have essentially equal sizes but other remarkably different characteristics, such as the number of N-H bonds, intrinsic dipole moment, and order of C-N bonds. Herein, we show that these cations have dramatically different effects over important fundamental and applied properties of resulting perovskites, including the orthorhombic-to-tetragonal and tetragonal-to-cubic phase transitions, microstructural development, ionic conductivity, I-V hysteresis, electronic carrier mobility, and stability against light-induced degradation. These effects are correlated with the characteristics of the large substituent cations and help pave the way for a better rational chemical design of halide perovskites.

Novel majority carrier accumulation insulated gate bipolar transistor with Schottky junction

Insulated gate bipolar transistor (IGBT) is the core of modern power semiconductor device, and has been widely used due to its excellent electrical characteristics. A novel majority carrier accumulation mode IGBT with Schottky junction contact gate semiconductor layer (AC-SCG IGBT) is proposed and investigated by TCAD simulation in this article. When the AC-SCG IGBT is in the on-state, a forward bias is applied to the gate. Due to the very low forward voltage drop (<i>V</i><sub>F</sub>) of the Schottky barrier diode, the potential of the gate semiconductor layer is almost equal to the gate potential, which can accumulate a large number of majority carrier electrons in the drift region. In addition to the electrons existing, these accumulated electrons increase the conductivity of the drift region, thus significantly reducing <i>V</i><sub>F</sub>. Therefore, the doping concentration of the drift region is not limited by <i>V</i><sub>F</sub>. The lightly doped drift region can make AC-SCG IGBT have a higher breakdown voltage (BV). Moreover, it also reduces the barrier capacitance in the turn-off process, thus the overall Miller capacitance is small, which can quickly turn off and reduce the turn-off time (<i>T</i><sub>off</sub>) and turn-off loss (<i>E</i><sub>off</sub>). The simulation results indicate that at the BV of 600 V, the <i>V</i><sub>F</sub> of 0.84 V for the proposed AC-SCG IGBT is reduced by 46.2% compared with that for the conventional IGBT (<i>V</i><sub>F</sub> of 1.56 V). The <i>E</i><sub>off</sub> of the AC-SCG IGBT (0.77 mJ/cm<sup>2</sup>) is reduced by 52.5% compared with that for the conventional IGBT (1.62 mJ/cm<sup>2</sup>), and the <i>T</i><sub>off</sub> (155.8–222.7 ns) is reduced by 30%. The contradiction between <i>V</i><sub>F</sub> and <i>E</i><sub>off</sub> is eliminated. In addition, the proposed AC-SCG IGBT has a better anti-latch-up capability and is coupled with its higher BV, so it has a larger forward biased safe operating area (FBSOA). The proposed novel structure meets the development requirements for future IGBT device performance, and has great significance for guiding the development of the power semiconductor device field.

PRESENTING FINANCIAL INFORMATION IN DIGITAL FORMATS AS A BASE FOR ANALYSIS AND AUDIT OF BUSINESS ACTIVITIES OF ENTERPRISES

he digitalization era of public relations is increasingly affecting the means of presenting information about the economic activities of an enterprise, in particular financial, in the context of a global pandemic, which was caused by the global COVID-19. Increasingly, in our environment, there is a transition from paper to electronic information carriers. The financial information generated by business entities both in Ukraine and in the world as a whole is no exception.The purpose of the study is to systematize the existing digital formats for presenting financial information as a basis for analyzing and auditing the business activities of enterprises in Ukraine.The basis of the study is the methodological recommendations on the use of Taxonomy UA XBRL IFRS, instructions for the revision of the Ukrainian IFRS taxonomy, specialized software products, legislative framework of Ukraine. The following methods were used: graphical (to visualize the results of the study), and grouping (to systematize the advantages and disadvantages of software that uses tax services to conduct e-audits)./Digital formats for the presentation of financial information were analyzed. They are the basis for the analysis and audit of the enterprise's activities. The structure and characteristics of the legal framework for the disclosure of financial information in electronic XBRL format in Ukraine were given. Comparative analysis of financial information in digital format XBRL and SAF-T UA were carried out.It has been determined that XBRL can be used as a basis for analyzing financial information in electronic format using special software, for example, to assess the financial condition, calculate indicators of financial stability, liquidity, solvency, business activity, enterprise profitability, etc. It has been proved that the electronic format of financial information SAF-T UA is used when conducting an electronic audit (e-audit) of taxpayers, and can also be used to calculate the tax burden (tax return, tax efficiency ratio) used by the State Tax Service of Ukraine for the purpose of control completeness of calculation and payment of relevant taxes and fees to the state budget.

Construction of visible light responsive GO-stimulated In2O3/BiVO4 Z-scheme heterostructure: Photocatalytic degradation of dye & antibiotics, anticancer activity and toxicity elimination

A ternary nanocomposite, In2O3/GO/BiVO4, was created using the hydrothermal process, establishing a heterojunction between In2O3 and BiVO4 with the addition of graphene oxide nanosheets. The synthesized materials underwent characterization using various standard analytical techniques, including diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), electron spin resonance spectroscopy (ESR), energy-dispersive X-ray (EDX), and transmission electron microscopy (TEM). The developed materials showed notable efficacy in degrading MB dye and antibiotics such as ciprofloxacin and tetracycline, when exposed to visible light in an aqueous suspension. The photocatalyst, 10 wt% In2O3/GO/BiVO4 (10IBG) showed better activity compared with the pure and other composite materials. The enhanced activity could be attributed to the synergistic effects of charge carrier separation and electron mediation facilitated by graphene oxide via Z-scheme pathway. The successful integration of graphene oxide in the heterostructure underscores its potential as a promising strategy for developing high-performance photocatalysts for the elimination of organic pollutants. Furthermore, the mechanism investigation underlying photocatalytic degradation of organic pollutants using the 10IBG heterostructure photocatalyst is conducted through trapping experiments, which indicates that the degradation is primarily contributedby superoxide radical anions (O2•-) and hydroxyl radicals (•OH). Moreover, 10IBG photocatalyst displayed remarkable anticancer activity against A549 lung cancer cell lines, whereas the cell viability was reduced from 18% in the dark medium to 58% when exposed to visible light. In terms of toxicity assessment, the 10IBG heterostructure photocatalyst demonstrated quick eradication of antibiotic toxicity and established itself as a promising and cost-effective photocatalyst for wastewater treatment.

Streamlines of the Poynting Vector and Chirality Flux around a Plasmonic Bowtie Nanoantenna.

The streamlines of the energy flux (Poynting vectors) and chirality flux as well as the intensity of the electric field around various plasmonic nanostructures (nanocube, nanocuboid, nanotriangle, hexagonal nanoplate and bowtie nanoantenna) induced by a circularly polarized (CP) or linearly polarized (LP) light were studied theoretically. The boundary element method combined with the method of moment was used to solve a set of surface integral equations, based on the Stratton-Chu formulation, for analyzing the highly distorted electromagnetic (EM) field in the proximity of these nanostructures. We discovered that the winding behavior of these streamlines exhibits versatility for various modes of the surface plasmon resonance of different nanostructures. Recently, using plasmonic nanostructures to facilitate a photochemical reaction has gained significant attention, where the hot carriers (electrons) play important roles. Our findings reveal a connection between the flow pattern of energy flux and the morphology of the photochemical deposition around various plasmonic nanostructures irradiated by a CP light. For example, numerical results exhibit vertically helical streamlines of the Poynting vector around an Au nanocube and transversely twisted-roll streamlines around a nanocuboid. Additionally, the behaviors of the winding energy and chirality fluxes at the gap and corners of a plasmonic bowtie nanoantenna, implying a highly twisted EM field, depend on the polarization of the incident LP light. Our analysis of the streamlines of the Poynting vector and chirality flux offers an insight into the formation of plasmon-enhanced photocatalysis.

The Creation of Multimode Luminescent Phosphor through an Oxygen Vacancy Center for High-Level Anticounterfeiting.

Integrating multimode optical properties into a single material simultaneously is promising for improving the security level of fluorescent anticounterfeiting. However, there has been a lack of affirmative principles and unambiguous mechanisms that guide the design of such material. Herein, we achieve color-tunable photoluminescence, long-lived persistent emission, thermally stimulated luminescence, and reversible photochromism in a Tb3+-activated Mg4Ga8Ge2O20 phosphor by employing the F-like color center as an energy reservoir. It is experimentally revealed that the role of oxygen vacancies in the lattice of Mg4Ga8Ge2O20 is assumed as the main trap for the photogenerated electronic carriers, which is the origin of metastable F-like color centers. The formed color centers with the estimated depths of 0.48-0.95 eV could suppress the recombination of electron-hole pairs, thus giving rise to good photochromism and persistent emission properties, while under various modes of stimulation such as thermal attack or photo radiation, a quick recombination of electron holes happens, accounting for the bright thermally stimulated luminescence and the accompanied color bleaching. Finally, we fabricate a flexible phosphor/polymer composite by encapsulating the developed phosphor into a polydimethylsiloxane matrix, and conceptual demonstration of the composite for the high-security fluorescent anticounterfeiting technology, by virtue of multimode optical phenomena as authentication signals.

Thermalization of radiation-induced electrons in wide-bandgap materials: A first-principles approach

The present study is concerned with simulating the thermalization of high-energy charge carriers (electrons and/or electron–hole pairs), generated by ionizing radiation, in diamond and β-Ga2O3. Computational tools developed by the nuclear/particle physics and electronic device communities allow for accurate simulation of charge-carrier transport and thermalization in the high-energy (exceeding ∼100 eV) and low-energy (below ∼10 eV) regimes, respectively. Between these energy regimes, there is an intermediate energy range of about 10–100 eV, which we call the “10–100 eV gap,” in which the energy-loss processes are historically not well studied or understood. To close this “gap,” we use a first-principles approach (density functional theory) to calculate the band structure of diamond and β-Ga2O3 up to ∼100 eV along with the phonon dispersion, carrier-phonon matrix elements, and dynamic dielectric function. Additionally, using the first-order perturbation theory (Fermi's golden rule/first Born approximation), we calculate the carrier-phonon scattering rates and the carrier energy-loss rates (impact ionization and plasmon scattering). With these data, we simulate the thermalization of 100-eV electrons and the generated electron–hole pairs by solving the semiclassical Boltzmann transport equation using Monte Carlo techniques. We find that electron thermalization is complete within ∼0.4 and ∼1.0 ps for diamond and β-Ga2O3, respectively, while holes thermalize within ∼0.5 ps for both. We also calculate electron–hole pair creation energies of 12.87 and 11.24 eV, respectively.

Highly efficient deep blue electroluminescent material with high and towards balanced carrier transmission performance based on hybrid local and charge-transfer (HLCT) excited state

Deep blue electroluminescent materials play a decisive role in organic light-emitting diodes (OLEDs). Herein, three novel deep blue molecules based on hybridized local and charge-transfer (HLCT) excited state were reported, namely CZFPY, CZFPI and TPAFPI. Single-crystal analysis of TPAFPI shows abundant intermolecular interactions, which restricts molecular rotation and suppresses structural vibrations, promotes TPAFPI achieved a high photoluminescence quantum yield (PLQY) up to 72 % in solid state. More importantly, these abundant intermolecular interactions significantly increase its carrier mobilities, with hole and electron mobilities as high as 1.2 × 10−5 cm2 V−1 s−1 and 5.4 × 10−6 cm2 V−1 s−1, respectively. Consequently, the non-doped OLED based on TPAFPI achieved excellent device performance, the maximum current efficiency (CEmax) is 12.4 cd/A, the maximum power efficiency (PEmax) is 14.0 lm W−1, the maximum external quantum efficiency (EQEmax) is 7.2 % with high device stability, the efficiency roll-off is only 4.7 % at 1000 cd m−2. What is more, the doped device of TPAFPI exhibits a higher EQEmax of 10.1 % with a higher color purity, the Commission International de L’Eclairage (CIE) coordinate is (0.15, 0.06), matching the National Television Standards Committee (NTSC) standard. The comprehensive performance of TPAFPI-based doped device is at the highest level in the field of deep blue OLEDs (0.06 ≤ CIEy ≤ 0.09).

PH-Dependent photocatalytic performance of faceted BiOBr semiconductor particles in degradation of dyes

Bismuth oxyhalides, such as bismuth-oxy-bromide (BiOBr), show high performance in photocatalytic oxidation of water pollutants. Process conditions, and in particular the pH of the solution, largely affect the photocatalytic efficacy, which is fundamentally poorly understood. We prepared {001} faceted bismuth-oxy-bromide (BiOBr), and determined by advanced AFM analysis that the surface charge of the {001} facet of BiOBr is slightly positive at acidic pH (pH 3) and significantly negative and increasing in negative surface charge in the order pH 6 < pH 9. Decomposition of MB or RhB by illumination of BiOBr is strongly favored by basic conditions (pH 9-10), as evident from discoloration experiments, and determination of the TOC as a function of time of illumination. Reference experiments show the pH dependent degradation profiles cannot be explained by differences in quantities of adsorption of the dye, but rather by the lifetime and/or quantity of BiOBr related photoexcited (surface) charge carriers (holes and electrons) – correlating with surface charge. Using MeOH and other scavengers, we show oxidation of MB or RhB is mainly induced by superoxide anions (•O2− radicals) at low pH and by holes or hydroxyl radicals at high pH – in agreement with surface charge induced band bending. This study provides novel understanding of the pH dependence of the rates of photocatalytic degradation of dyes using BiOBr photocatalysts.

Melanin-inspired conductive thin films for multimodal-sensing wearable on-skin electronics

Electronic skins (e-skins), composed of various flexible sensors, mimic the sensing functions of human skin aiming for both healthcare monitoring and prosthetics development applications. So far different multi-component e-skin devices aimed to fulfill different requirements (biocompatibility, skin adhesion, flexibility, conductivity, sensitivity towards biological stimuli and stretchability) have been reported. However, the obtaining of such devices combining all the above requirements within a single material that simplifies not only cost but specially functioning still remains a challenge. For this, catechol-based materials have attracted special attention due to their adhesive properties, compatibility and melanin-like electrical conduction. In this work, 2,3,6,7,10,11 – hexahydroxy triphenylene (HHTP) was used as catechol moiety in a typical melanin-like polymerization, resulting in a free-standing melanin-inspired film (MN-film). The obtained MN-film showcased good conductivities with dual charge carriers (electrons and ions) under different environments, i.e. pure water and buffers simulating sweat. Large biocompatibility, adhesion and conformability to skin were obtained as well, allowing to implement the film in wearable electronic on-skin devices on porcine skin. Measurements in wearable devices indicated large sensitivity towards different stimuli (strain, motion and temperature) under sweat-like conditions.

Three-dimensional bound states of cylindrical quantum heterostructures with position-dependent mass carriers

We present a comprehensive spectral analysis of cylindrical quantum heterostructures by considering effective electronic carriers with position-dependent mass for five different kinetic-operator orderings. We obtain the bound energy eigenstates of particles in a three-dimensional cylindrical nanowire under a confining hyperbolic potential with both open and closed boundary conditions in the radial and the axial directions. In the present model we consider carriers with continuous mass distributions within the dot with abrupt mass discontinuities at the barriers, moving in a quantum dot that connects different substances. Continuity of mass and potential at the interfaces with the external layers result as a particular case. Our approach is mostly analytical and allows a precise comparison among von Roos ordering classes.

Asymmetry of Structural and Electrophysical Properties of Symmetrical Titania Nanotubes as a Result of Modification with Barium Titanate

Anodic titania nanotubes (TiO2-NT) are very promising for use in photocatalysis and photovoltaics due to their developed surface, symmetrical structure and conductive properties, which, moreover, makes them a convenient matrix for creating various nanocomposites. Herein we propose a new facile way of synthesizing symmetrical TiO2-NT followed by a modification with barium titanate (BaTiO3) nanoparticles, combining the advantages of electrochemical oxidation and hydrothermal synthesis. The electrophysical and optoelectronic properties of the formed nanocomposites have been studied. An asymmetry of the current–voltage characteristics was revealed. It is shown that during the barium titanate deposition, a symmetry-breaking nanoheterojunction TiO2/BaTiO3 is formed. Using EPR spectroscopy, paramagnetic defects (titanium, barium and oxygen vacancies) in the samples were determined. It was observed for the first time that upon illumination of titania nanotubes modified with BaTiO3, the asymmetrical separation of photoexcited charge carriers (electrons and holes) between TiO2-NT and BaTiO3 occurs, followed by the capture of electrons and holes by defects. As a result, the photoinduced charge accumulates on the defects.

Unveiling the potential of two-dimensional Janus ScXAlY (X/Y=P, As) materials and heterostructures in visible-light-driven photocatalytic water splitting

Two-dimensional (2D) material with Janus-induced built-in electric field, has become a research focus arising from their characteristic physical and chemical properties, especially in photocatalytic water splitting applications. Herein, we introduce a novel family of 2D Janus materials, named ScXAlY (X/Y = P, As), and prove these Janus materials and their heterostructures as promising water splitting photocatalytic candidate materials, leveraging first-principles calculations. All Janus structures and heterostructures exhibit strong dynamical, thermal, and mechanical stabilities. These 2D Janus ScXAlY materials possess wide band gaps, excellent electronic carrier mobilities, and appropriate band edges to facilitate overall water splitting, and moreover can attain Janus-induced built-in electric field effect. Interestingly, the heterostructures (ScXAlY/ScXAlY) surpass the individual materials in performance, demonstrating enhanced solar-to-hydrogen (STH) efficiencies (>30 %) and increscent electrostatic potential differences (>0.85 eV). Furthermore, they show comprehensive photoabsorption across the visible light spectrum, with peak absorptions more than doubling those of the single materials. These heterostructures also display effective spatial separation of electrons and holes which can further boosting their photocatalytic capabilities. Our findings underscore the potential of Janus ScXAlY materials and their heterostructures, in facilitating visible-light-driven photocatalytic water splitting, showcasing a promising avenue for advancement in this burgeoning field.

Tunable Electronic Properties, Carrier Mobility, and Contact Characteristics in Type-II BSe/Sc2CF2 Heterostructures toward Next-Generation Optoelectronic Devices.

Conducting heterostructures have emerged as a promising strategy to enhance physical properties and unlock the potential application of such materials. Herein, we conduct and investigate the electronic and transport properties of the BSe/Sc2CF2 heterostructure using first-principles calculations. The BSe/Sc2CF2 heterostructure is structurally and thermodynamically stable, indicating that it can be feasible for further experiments. The BSe/Sc2CF2 heterostructure exhibits a semiconducting behavior with an indirect band gap and possesses type-II band alignment. This unique alignment promotes efficient charge separation, making it highly promising for device applications, including solar cells and photodetectors. Furthermore, type-II band alignment in the BSe/Sc2CF2 heterostructure leads to a reduced band gap compared to the individual BSe and Sc2CF2 monolayers, leading to enhanced charge carrier mobility and light absorption. Additionally, the generation of the BSe/Sc2CF2 heterostructure enhances the transport properties of the BSe and Sc2CF2 monolayers. The electric fields and strains can modify the electronic properties, thus expanding the potential application possibilities. Both the electric fields and strains can tune the band gap and lead to the type-II to type-I conversion in the BSe/Sc2CF2 heterostructure. These findings shed light on the versatile nature of the BSe/Sc2CF2 heterostructure and its potential for advanced nanoelectronic and optoelectronic devices.

Construction of multiple channels for electron transport in In2S3/In2O3/rGO heterojunctions to boost photocatalytic CO2 conversion to C2+ hydrocarbons

Constructing hybrids to accelerate the charge carrier separation and electron transport, and then decrease the electrons loss should be effective in the CO2 conversion into C2+ hydrocarbon fuels. In2S3/In2O3 (IS/IO) heterojunctions were in situ formed and decorated on reduced graphene oxide (rGO) sheets, realizing the construction of multiple channels for electron transport. Upon illumination, IS/IO-rGO nanocomposites not only significantly improved the conversion of CO2 to CO and CH4, but also allowed the formation of C2+ hydrocarbons (C2H4, C2H6, C3H6 and C3H8) under atmospheric conditions, and the total selectivity of C2+ even reached about 35 %. The synergistic effect of the heterojunctions and rGO, with multiple channels for electron transport, accelerates the charge carrier separation/transfer and increases the applied efficiency of electrons, availing more electrons accumulated on the surface of the composite. Eventually, there are sufficient electrons to participate in the reduction of CO2 to CO, CH4 and C2+ hydrocarbons.

Room-temperature wavelike exciton transport in a van der Waals superatomic semiconductor.

The transport of energy and information in semiconductors is limited by scattering between electronic carriers and lattice phonons, resulting in diffusive and lossy transport that curtails all semiconductor technologies. Using Re6Se8Cl2, a van der Waals (vdW) superatomic semiconductor, we demonstrate the formation of acoustic exciton-polarons, an electronic quasiparticle shielded from phonon scattering. We directly imaged polaron transport in Re6Se8Cl2 at room temperature, revealing quasi-ballistic, wavelike propagation sustained for a nanosecond and several micrometers. Shielded polaron transport leads to electronic energy propagation lengths orders of magnitude greater than in other vdW semiconductors, exceeding even silicon over a nanosecond. We propose that, counterintuitively, quasi-flat electronic bands and strong exciton-acoustic phonon coupling are together responsible for the transport properties of Re6Se8Cl2, establishing a path to ballistic room-temperature semiconductors.