Search

Three-dimensional (3D) reduced graphene oxide (rGO)/Ti2CTx MXene hybrid aerogels were effectively prepared by a two-step method involving hydrothermal reaction and freeze-drying. The intimately coupled rGO/Ti2CTx hybrid aerogel combined high electrical conductivity, large interlayer spacing, and excellent mechanical stability of Ti2CTx, which not only effectively prevents the self-restacking of Ti2CTx nanosheets, exposes more active sites exposed, and improves the volume change during the charge/discharge process but also increases the accessibility of ions and promotes the rapid transfer of ions/electrons. As a result, rGO/Ti2CTx 17.5–2.5 as the working electrode of electric double layer capacitors delivers a large specific capacity (107.05 F g−1 at 0.5 A g−1 in a 1M Na2SO4 electrolyte), a high rate capability (maintains 30% of its initial capacitance at 10 A g−1, which is much better than rGO and Ti2CTx), and excellent long-term large-current cycle stability (the initial capacitance remains above 71.1% after 10 000 cycles at 1 A g−1). In addition to providing a high-performance electrode for supercapacitors, this study proposes an efficient and time-saving strategy for constructing 3D structures from 2D materials. [ABSTRACT FROM AUTHOR]

Zeolitic Imidazolate Frameworks-8 (ZIF-8) is commonly used as an ideal precursor for non-noble metal catalysts because of its high specific surface area, ultra-high porosity, and N-rich content. Upon pyrolyzing ZIF-8 at 900 °C in Ar, the resulting material, referred to as Z8, displayed good activity toward the oxygen reduction reaction (ORR). Then the ZIF-8 was mixed with various conductive carbon materials, such as multiwall carbon nanotubes (MWCNTs), Acetylene black (ACET), Vulcan XC-72R (XC-72R), and Ketjenblack EC-600JD (EC-600JD), to form Z8 composites. The Z8/MWCNTs composite exhibited enhanced ORR activity owing to its network structure, meso-/microporous hierarchical porous structure, improved electrical conductivity, and graphitization. Subsequently, iron and nitrogen co-doping is achieved through the pyrolysis of a mixture comprising Fe, N precursor, and ZIF-8/MWCNTs, which is denoted as FeN-Z8/MWCNTs. The intrinsically high electrical conductivity of MWCNTs facilitated efficient electron transfer during the ORR, while the meso-/microporous hierarchical porous structure and network structure of Fe, N co-doped ZIF-8/MWCNTs promoted oxygen transport. The presence of Fe-containing species in the catalyst acted as activity centers for ORR. This strategy of preparing Z8 composites and modifying them with Fe, N co-doping offers an insightful approach to designing cost-effective electrocatalysts. [ABSTRACT FROM AUTHOR]

Surface tension and interfacial tension are crucial to the study of nanomaterials. Herein, we report a solubility method using magnesium oxide nanoparticles of different radii (1.8–105.0 nm, MgO NPs) dissolved in pure water as a targeted model; the surface tension and interfacial tension (and their temperature coefficients) were determined by measuring electrical conductivity and combined with the principle of the electrochemical equilibrium method, and the problem of particle size dependence is discussed. Encouragingly, this method can also be used to determine the ionic (atomic or molecular) radius and Tolman length of nanomaterials. This research results disclose that surface/interfacial tension and their temperature coefficients have a significant relationship with particle size. Surface/interfacial tension decreases rapidly with a radius <10 nm (while the temperature coefficients are opposite), while for a radius >10 nm, the effect is minimal. Especially, it is proven that the value of Tolman length is positive, the effect of particle size on Tolman length is consistent with the surface/interfacial tension, and the Tolman length of the bulk does not change much in the temperature range. This work initiates a new era for reliable determination of surface/interfacial tension, their temperature coefficients, ionic radius, and Tolman length of nanomaterials and provides an important theoretical basis for the development and application of various nanomaterials. [ABSTRACT FROM AUTHOR]

Transparent conducting oxides with p-type conductivity hold immense potential for various electronic applications. The role of native point defects in delafossite CuMO 2 (M = Al, Ga, In) as the source of p-type conductivity has been widely acknowledged. However, understanding the primary defects governing the electrical properties and devising strategies for improvement remains a critical challenge. In this study, we employ range-separated hybrid density functional calculations to elucidate the impact of acceptor defects and their interactions with hydrogen on electrical conductivity. Our findings demonstrate that hydrogen plays a pivotal role in controlling p-type conductivity in these oxides. Our investigation reveals that the interactions between hydrogen interstitial H i and copper vacancy V C u lead to the formation of stable complexes that are electrically inactive. Considerable binding energies are observed for H i – V C u complexes, indicating that they are highly bound complexes with low formation energy and, thus, high concentrations under both O-rich and O-poor conditions. A second hydrogen can be bound to V C u to form 2H i – V C u complexes, which are thermodynamically stable and function as a single donor. Furthermore, hydrogen can bind with the antisite acceptor defects, Cu M , forming H i – Cu M complexes. However, the lower binding energies associated with these complexes suggest likely dissociation into isolated H i and Cu M at relatively low temperatures. By shedding light on the strong influence of hydrogen passivation of acceptor defects, this study offers valuable insights into p-type conductivity in delafossite CuMO 2. [ABSTRACT FROM AUTHOR]

Boron carbonitride (BCN) films containing hybridized bonds involving B, C, and N over wide compositional ranges enable an abundant variety of new materials, properties, and applications; however, their electronic performance is still limited by the presence of structural and electronic defects, yielding sluggish mobility and electrical conductivity. This work reports on mechanically stable BCN films and their corresponding optical and electronic properties. The ternary BCN films consisting of hybridized B–C–N bonds have been achieved by varying N2 flow by the radio frequency magnetron sputtering method. The BCN films show a bandgap value ranging from 3.32 to 3.82 eV. Hall effect measurements reveal an n-type conductivity with an improved hall mobility of 226 cm2/V s at room temperature for the optimal film. The n-BCN/p-Si heterojunctions exhibit a nonlinear rectifying characteristic, where the tunneling behavior dominates the injection regimes due to the density of defects, i.e., structural disorder and impurities. Our work demonstrates the tunable electrical properties of BCN/Si p–n diodes and, thus, is beneficial for the potential application in the fields of optics, optoelectronics, and electrics. [ABSTRACT FROM AUTHOR]

MXenes exhibit significant potential in thermoelectric materials owing to their exceptional electrical conductivity; however, their limited number of semiconductors restricts their application. Thus, it is highly desirable to expand the MXene family beyond carbides and nitrides to broaden their applications in thermoelectricity. In this work, we systematically investigate the thermoelectric transport of Ti2OX2 (X = F, Cl) MOene through comprehensively evaluating the electron–phonon coupling (EPC) from first principles. Our findings first emphasize the limitations of the deformation potential theory method and stress the importance of considering EPC. Ti2OF2 (Ti2OCl2) monolayer exhibits exceptional electronic transport, with Seebeck coefficients reaching 1483.87 (1206.22) μV/K and electrical conductivity reaching 9.5 × 105 (7.6 × 105) Ω−1 m−1 at room temperature for its N-type counterpart. Additionally, the presence of degenerate multiple valleys and peaks significantly enhances their electronic transport. For phonon transport, EPC results in a significant reduction in lattice thermal conductivity (kL) [e.g., at 300 K with 1.44 × 1015 (1.68 × 1015) cm−2 of hole, the reduction is 86.3% (73.3%) for Ti2OF2 (Ti2OCl2)]. Additionally, their kL demonstrates a strong correlation with the density of states at corresponding Fermi levels. Moreover, the kL and total thermal conductivity of P-type Ti2OF2 show T-independence, making it suitable for applications in aviation and thermal insulation materials. Finally, N-type Ti2OF2 and Ti2OCl2 demonstrate superior zT values of 0.63 and 0.9 at 900 K, respectively. This study provides in-depth insights into the superior thermoelectric properties of Ti2OX2 (X = F, Cl) MOene with considering EPC, providing a novel platform for the next-generation thermoelectric field. [ABSTRACT FROM AUTHOR]

A novel interfacial resistance-free (IRF) bifunctional camouflage (transparent and invisible) device is proposed in this paper. The thermal and electric conductivities of the shell and background are the same to eliminate the interfacial resistance. The IRF bifunctional camouflage device can operate in thermal–electric fields based on the neutral inclusion method. The distribution of isotherm and equipotential lines are studied quantitatively by the simulations. It is confirmed that the IRF bifunctional camouflage device with arbitrary natural materials can effectively achieve not only the invisible function but also the transparent function in thermal–electric fields. This method provides a window to the realization of bifunctions and the development of multi-physics fields. [ABSTRACT FROM AUTHOR]

The addition of molecular dopants into organic semiconductors (OSCs) is a ubiquitous augmentation strategy to enhance the electrical conductivity of OSCs. Although the importance of optimizing OSC–dopant interactions is well-recognized, chemically generalizable structure–function relationships are difficult to extract due to the sensitivity and dependence of doping efficiency on chemistry, processing conditions, and morphology. Computational modeling for an integrated OSC–dopant design is an attractive approach to systematically isolate fundamental relationships, but requires the challenging simultaneous treatment of molecular reactivity and morphology evolution. We present the first computational study to couple molecular reactivity with morphology evolution in a molecularly doped OSC. Reactive Monte Carlo is employed to examine the evolution of OSC–dopant morphologies and doping efficiency with respect to dielectric, the thermodynamic driving for the doping reaction, and dopant aggregation. We observe that for well-mixed systems with experimentally relevant dielectric constants, doping efficiency is near unity with a very weak dependence on the ionization potential and electron affinity of OSC and dopant, respectively. At experimental dielectric constants, reaction-induced aggregation is observed, corresponding to the well-known insolubility of solution-doped materials. Simulations are qualitatively consistent with a number of experimental studies showing a decrease of doping efficiency with increasing dopant concentration. Finally, we observe that the aggregation of dopants lowers doping efficiency and thus presents a rational design strategy for maximizing doping efficiency in molecularly doped OSCs. This work represents an important first step toward the systematic integration of molecular reactivity and morphology evolution into the characterization of multi-scale structure–function relationships in molecularly doped OSCs. [ABSTRACT FROM AUTHOR]

In view of the inherent pseudocapacitance, rich redox pairs (Nb5+/Nb4+ and Nb4+/Nb3+), and high lithiation potential (1.0–3.0 V vs Li/Li+), Nb2O5 is considered a promising anode material. However, the inherent low electronic conductivity of Nb2O5 limits its lithium storage performance, and the rate performance after carbon modification is still unsatisfactory because the intrinsic conductivity of Nb2O5 has not been substantially improved. In this experiment, taking the improvement of the intrinsic electrical conductivity of Nb2O5 as the guiding ideology, we prepared F-doped Nb2O5@fluorocarbon composites (F–Nb2O5@FC) with a large number of oxygen vacancies by one-step annealing. As the anode electrode of lithium-ion batteries, the reversible specific capacity of F–Nb2O5@FC reaches 150 mA g−1 at 5 A g−1 after 1100 cycles, and the rate performance is particularly outstanding, with a capacity up to 130 mA g−1 at 16 A g−1, which is far superior to other Nb2O5@carbon-based anode electrodes. Compared with other single conductivity sources of Nb2O5@carbon-based composites, the electrical conductivity of F–Nb2O5@FC composites is greatly improved in many aspects, including the introduction of free electrons by F− doping, the generation of oxygen vacancies, and the provision of a three-dimensional conductive network by FC. Through analytical chemistry (work function, UV–Vis diffuse reflectance spectroscopy, and EIS) and theoretical calculations, it is proved that F–Nb2O5@FC has high electrical conductivity and realizes rapid electron transfer. [ABSTRACT FROM AUTHOR]

Roughly, 50% of primary energy worldwide is rejected as waste heat over a wide range of temperatures. Waste heat above 573 K has the highest Carnot potential (> --> 50 %) to be converted to electricity due to higher Carnot efficiency. Thermoelectric (TE) materials have gained significant attention as potential candidates for efficient thermal energy conversion devices. Silicon nanowires (SiNWs) are promising materials for TE devices due to their unique electrical and thermal properties. In this study, we report the successful fabrication of high-quality double-sided SiNW arrays using advanced techniques. We engineered the double-sided structure to increase the surface area and the number of TE junctions, enhancing TE energy conversion efficiency. We also employed non-agglomeration wire tip engineering to ensure uniformity of the SiNWs and designed effective Ohmic contacts to improve overall TE efficiency. Additionally, we post-doped the double-sided SiNW arrays to achieve high electrical conductivity. Our results showed a significant improvement in the TE performance of the SiNW array devices, with a maximum figure-of-merit (ZT) value of 0.24 at 700 K, fabricated from the single SiNW with ZT of 0.71 at 700 K in our previous work [Yang et al., Nat. Commun. 12(1), 3926(2021)]. [ABSTRACT FROM AUTHOR]

Glutaronitrile (GN) doped with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at concentrations below and above the room-temperature conductivity optimum near 1M of Li salt is investigated using dielectric spectroscopy and shear rheology. The experiments are carried out from ambient down to the glass transition temperature Tg, which increases considerably as LiTFSI is admixed to GN. As the temperature is lowered, the conductivity optimum shifts to lower salt concentrations, while the power-law exponents connecting resistivity and molecular reorientation time remain smallest for the 1M composition. By contrast, the rheologically detected time constants, as well as those obtained using dielectric spectroscopy, increase monotonically with increasing Li salt concentration for all temperatures. It is demonstrated that the shear mechanical measurements are, nevertheless, sensitive to the 1M conductivity optimum, thus elucidating the interplay of the dinitrile matrix with the mobile species. The data for the Li doped GN and other nitrile solvents all follow about the same Walden line, in harmony with their highly conductive character. The composition dependent relation between the ionic and the reorientational dynamics is also elucidated. [ABSTRACT FROM AUTHOR]

In this report, the high-temperature transport properties of (Dy1−xCax)(Zr0.2Hf0.2Sn0.2Ti0.2Ge0.2)O7 pyrochlore oxides with x = 0, 0.05, and 0.1 are studied in dry and humid air. The phase composition and crystal structure were determined by using x-ray and neutron diffraction. The addition of calcium to the structure caused an increase in the concentration of oxygen vacancies, indicating an ionic charge compensation mechanism. Electrical studies allowed us to determine the total electrical conductivity as a function of the synthesis atmosphere and pH2O. The electrical conductivity turned out to be at the level of ∼10−3 S/cm at 800 °C, and only a slight effect of the presence of protonic defects in the structure on the total electrical conductivity was observed. In general, the samples had a low electrical conductivity with a relatively high activation energy of conduction. [ABSTRACT FROM AUTHOR]

In this study, the basic properties of Ba2AgSi3 were investigated in detail from both experimental and computational viewpoints. Polycrystalline Ba2AgSi3 formed by an arc-melting apparatus under an argon atmosphere was ground into powders, and then powder samples were sintered using the spark plasma sintering method. Both n-type and p-type samples were obtained. This may be due to a slight deviation from the stoichiometric composition. The energy bandgap of Ba2AgSi3 was measured to be around 0.17 eV from the temperature dependence of electrical conductivity and was in agreement with that by first-principles calculations. Sintered samples exhibited a high Seebeck coefficient of −273 μV K−1 and a high power factor of 0.38 mW m−1 K−2 at 307 K for n-type samples. They were 217 μV K−1 and 0.23 mW m−1 K−2, respectively, at 320 K for p-type samples. The electronic structures of impurity-doped Ba2AgSi3 were also discussed using first-principles calculations to investigate the insertion site of impurity atoms. The calculations suggest that the substitution of B (P) at any Si site shifts the Fermi level and transforms it into p-type (n-type) semiconductors. On the other hand, substitution of Ba or Ag sites with B or P is unlikely to occur in terms of formation energy. [ABSTRACT FROM AUTHOR]

The intrinsically low electrical conductivity and poor structural fragility of MnO2 have significantly hampered the zinc storage performance. In this work, Ba2+-implanted δ-MnO2 nanosheets have been hydrothermally grown on a carbon cloth (Ba–MnO2@CC) as an extremely stable and efficient cathode material of aqueous zinc-ion batteries. The three-dimensionally porous architecture composed of interwoven thin MnO2 nanosheets effectively shortens the electron/ion transport distances, enlarges the electrode/electrolyte contact area, and increases the active sites for the electrochemical reaction. Meanwhile, Ba2+ could function as an interlayer pillar to stabilize the crystal structure of MnO2. Consequently, the as-optimized Ba–MnO2@CC exhibits remarkable Zn2+ storage capabilities, such as a high capacity (305 mAh g−1 at 0.2 A g−1), prolonged lifespan (95% retention after a 200-cycling test), and superb rate capability. The binder-free cathode is also applicable for flexible energy storage devices with attractive properties. The present investigation provides important insights into designing advanced cathode materials toward wearable electronics. [ABSTRACT FROM AUTHOR]

Ti-doped In 2 O 3 thin films with varying Ti contents are prepared by partial reactive co-sputtering using ceramic In 2 O 3 and metallic Ti targets and characterized by in situ x-ray photoelectron spectroscopy, electrical conductivity, and Hall-effect measurements. For a substrate temperature of 400 ° C , the carrier concentration increases faster than the Ti content and saturates at ≈ 7.4 × 10 20 c m − 3 . Based on these results, it is suggested that Ti does not directly act as donor in In 2 O 3 but is rather forming TiO 2 precipitates and that the related scavenging of oxygen generates oxygen vacancies in In 2 O 3 as origin of doping. Neutralization of oxygen vacancies is, therefore, suggested to be origin of the limitation of the carrier concentration in Ti-doped In 2 O 3 films. [ABSTRACT FROM AUTHOR]

In recent years, organic–inorganic hybrid perovskite (PVK) devices have attracted widespread attention with their high absorption coefficient and low-cost fabrication process. Formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) have been reported to obtain high power conversion efficiencies (PCEs) due to the narrow bandgap. Zinc oxide (ZnO) has better electrical conductivity and high transmittance than tin (IV) dioxide (SnO2). However, the deprotonation behavior of ZnO limits its use in formamidinium (FA) or methylammonium (MA) devices, so it is mostly used in all-inorganic PSCs. In this work, to avoid the deprotonation behavior of ZnO, we prepared FAPbI3 PSCs using ZnO/SnO2 as bilayer electron transporting layers (ETLs), which improved the conductivity of the ETLs and promoted electron extraction and transfer. In addition, the decrease in the oxygen vacancy (Ov) on the bilayer ETLs contributed to the suppression of the non-radiative recombination of the device, thus enabling the achievement of a higher fill factor. As a result, the modified ETLs increased the PCE of FAPbI3 PSCs from 20.24% to 21.42% and improved the stability of the devices. The PCE of unpackaged devices increased steadily to 21.91% when stored in an N2 atmosphere for 183 days. [ABSTRACT FROM AUTHOR]

Single-turn coil (STC) is a destructive pulse magnet aiming at a 100–300 T ultra-high magnetic field. A thermal–electrical coupling model, in which the solid–liquid phase transition process is considered, is proposed. The effects of solid–liquid phase transition on pressure, temperature, and electrical conductivity are investigated. The results show that the compressed and stretched regions coexist simultaneously, and the distribution of both regions changes with time during discharging. Moreover, the region with the highest current density is inside the conductor, since the phase transition reduces the electrical conductivity of the region near the inner surface of STCs. By comparison, the simulation results are highly consistent with the measured data, and the necessity of considering the phase transition process is validated. The results obtained in this work are helpful for understanding the thermodynamic process of STCs during discharge. [ABSTRACT FROM AUTHOR]

PbTe-based compounds are excellent candidates for the different types of optical detector applications from near to far IR ranges. In the present work, a technology has been developed for the fabrication of Pb 1 − x Sn x Te compositions, doped with In, on a thin amorphous substrate (polyimide). The film preparation was performed by the electron gun evaporation method. The systematic study of structure and transport properties (Hall coefficient and electric conductivity) in the entire temperature range of 10–300 K for Pb 1 − x Sn x Te:In films (x = 0 , 0.1, 0.2) was investigated. It was studied that the photoconductivity of the films in the telecom wavelength range, including kinetics, sensitivity, and noise equivalent power, has been conducted and it discovered persistent photoconductivity for all compositions at the temperature T < 21 K. The results of the work have promising potential to use poly(nano) crystalline Pb 1 − x Sn x Te:In films on an amorphous substrate both for photodetection in the telecom wavelength range and for the creation of all-optical neuromorphic systems, cooled memory, and logic elements operating at the low energy of laser pulses. [ABSTRACT FROM AUTHOR]

Despite extensive studies of spin transport in metallic structures, it remains a challenge to achieve spin relaxation length well above 1 μm in metals even at low temperatures. We explore nonlocal spin transport in Cu channels with a cross section of 0.5 × 0.5 μm2, which exhibit superior values of electrical conductivity and residual resistivity ratio (RRR). Based on structures fabricated in a single batch, we found an average spin relaxation length of λ C u = 3.2 ± 0.7 μ m and an average spin relaxation time of τs = 120 ± 50 ps at 30 K. Substantial variations of λ C u , RRR, and resistivity ρ C u are found among the structures and the three quantities correlate well to one another. The most conductive Cu channel in the batch yields λ C u = 5.3 ± 0.8 μ m and τ s = 250 ± 80 ps. These superior values exceed expectations for metals and can be attributed to reduced spin relaxation from grain boundaries and surfaces. [ABSTRACT FROM AUTHOR]

Adding Fe3O4 nanoparticles to composites of [Fe(Htrz)2(trz)](BF4) spin-crossover polymer and polyaniline (PANI) drives a phase separation of both and restores the molecular structure and cooperative effects of the spin-crossover polymer without compromising the increased conductivity gained through the addition of PANI. We observe an increased on-off ratio for the DC conductivity owing to an enlarged off state resistivity and a 20 times larger AC conductivity of the on state compared with DC values. The Fe3O4 nanoparticles, primarily confined to the [Fe(Htrz)2(trz)](BF4) phase, are ferromagnetically coupled to the local moment of the spin-crossover molecule suggesting the existence of an exchange interaction between both components.

When it comes to simulate or calculate an optoelectronic tweezer (OET) response for a microparticle suspended in a given medium, a precise electrical conductivity (later referred to as conductivity) value for the microparticle is critical. However, there are not well-established measurements or well-referenced values for microparticle conductivities in the OET realm. Thus, we report a method based on measuring the escape velocity of a microparticle with a standard OET system to calculate its conductivity. A widely used 6 μm polystyrene bead (PSB) is used for the study. The conductivity values are found to be invariant around 2×10-3 S/m across multiple different aqueous media, which helps clarify the ambiguity in the usage of PSB conductivity. Our convenient approach could principally be applied for the measurement of multiple unknown OET-relevant material properties of microparticle-medium systems with various OET responses, which can be beneficial to carry out more accurate characterization in relevant fields. [ABSTRACT FROM AUTHOR]

The electrical conductivity of Na2O substituted zinc borate glasses has been studied in the frequency range of 10 mHz to 1 MHz and in the temperature range from 313 to 573 K. The conduction mechanism has been ascertained using the values of the frequency exponent (s) extracted from the fitting of experimental data of the real part of electric conductivity in light of the Almond–West equation. Depending on the glass composition, the ac conduction in the glasses happened via correlated barrier hopping and non-overlapping small polaron tunneling conduction models. The electric modulus studies support the assertion of composition dependent conduction mechanisms. Furthermore, electronic conduction and ionic conduction have been studied from impedance investigations. Equivalent circuit models were used to fit the Nyquist and Bode plots of each sample at the temperatures under consideration. It has been found that the activation energy values calculated from conductivity, electric modulus, and impedance measurements are more or less the same. [ABSTRACT FROM AUTHOR]

Thermoelectric transport properties of Janus monolayers M2P2S3Se3 (M = Zn and Cd) are investigated by the first-principles based transport theory. The Zn2P2S3Se3 and Cd2P2S3Se3 monolayers are indirect-gap semiconductors. The high polarizability of M-Se/S bonds in the MS3Se3 distorted octahedrons leads to anharmonic phonon behavior, which produces an intrinsic lattice thermal conductivity (κl) as low as 1.06 and 1.99 W m−1 K−1 at 300 K for Zn2P2S3Se3 and Cd2P2S3Se3 monolayers, respectively. The lower κl of the Zn2P2S3Se3 monolayer is mainly attributed to more pronounced flat modes of the phonon dispersion in a frequency range of 1–1.7 THz caused by the softer Zn–Se/S bonds. The polar optical phonon scattering of carriers surprisingly plays a dominant role in carrier transport of both the monolayers, which greatly suppresses the electrical conductivity and thereby the power factor by about an order of magnitude. The predicted figure of merit (zT) increases monotonically with the temperature at the optimal carrier density, and at the operating temperature of 1200 K, it reaches an optimal value of 0.86 at an optimal electron density of ∼ 1.5 × 1 0 13 cm−2 for the n-type Zn2P2S3Se3 monolayer and 0.30 at an optimal electron density of ∼ 7 × 1 0 12 cm−2 for the n-type Cd2P2S3Se3 monolayer. [ABSTRACT FROM AUTHOR]

Organic/inorganic thermoelectric hybrids demonstrate great potential for wearable applications. However, their scalability is hindered by an inferior power factor (S 2 σ). Nowadays, achieving deep optimization of S 2 σ necessitates a strategy to decouple the Seebeck coefficient (S) and electrical conductivity (σ). In this work, we propose a strategy to break the coupling between S and σ by constructing a Schottky interface that exhibits an energy-filtering effect. We validate the feasibility of this approach using a PANI/TiN–TiO2/carbon paper. The results demonstrate a 1.16-fold increase in σ and a 1.08-fold increase in S in PANI/TiN–TiO2/carbon paper achieved through the construction of a Schottky-type TiN/TiO2 interface. The separation of hole/electron at the TiN/TiO2 interface serves as the scattering center for ionized impurity scattering and facilitates the transport pathway for charge carriers. These factors are crucial in determining the simultaneous optimization of S and σ , respectively. Additionally, the energy-filtering effect of the TiN/TiO2 interface plays a positive role in the ionized impurity scattering mechanism by selectively filtering out low-energy carriers. This further strengthens decoupling of the thermoelectric properties. The 14.9% PANI/11.2% TiN–14.5% TiO2/59.44% carbon paper displays the highest S 2 σ and achieves a high ZT value of 223.6 μVm−1 K−2 and 0.31 at 300 K, highlighting the advantages of PANI-based thermoelectric hybrids. This work provides valuable guidance for the design of thermoelectric hybrids incorporating multi-interface morphology. [ABSTRACT FROM AUTHOR]

The growing demand for real-time ultraviolet (UV) monitoring calls for a simple, rapid, and low-cost strategy to prepare UV photodetectors (PDs). We prepare a wearable real-time UV PD based on hydrogenated titanium dioxide film synthesized by radio frequency atmospheric pressure plasma. The conductivity of our hydrogenated titanium dioxide is improved to 10.2 S cm−1, nine orders of magnitude higher than that of pristine titanium dioxide after 10 min plasma treatment. Plasma hydrogenation disrupts the surface crystal structure, introducing oxygen vacancies (OVs) that create self-doped titanium(III) and titanium(II) species. First-principles calculations indicate that the OVs raise the Fermi level of TiO2 and distort the lattice locally. Our optimized film has a distinctive periodic switching characteristic under intermittent illumination; its responsivity is good from 280 to 400 nm, peaking at 632.35 mA W−1 at 365 nm. The fabricated wearable sensor based on the optimized film effectively monitors the daily variation of ambient UV intensity in three typical weather types, transferring its data to a smartphone via Wi-Fi. [ABSTRACT FROM AUTHOR]

The low electrical conductivity and catalytic activity of transition metal sulfides have been identified as the primary factors limiting their application in the field of electrocatalytic water splitting. In this study, FeS 2 and Co-FeS x were initially synthesized through a hydrothermal method, followed by further annealing in an NH 3 atmosphere to obtain Co,N-FeS x. The introduction of Co led to adjustments in the electronic structure, resulting in the formation of FeS 2 /FeS (FeS x) heterojunctions that facilitated accelerated charge transfer. Simultaneously, Co element doping increased the electrochemical active surface area, providing more active sites for the reactions. N element doping, on the other hand, introduced sulfur vacancies, thereby enhancing electrical conductivity and improving charge transfer efficiency. As a result, Co,N-FeS x exhibited significantly higher activities for the oxygen evolution reaction (OER) and overall water splitting compared to FeS 2 , with overpotentials of 290 mV and 330 mV, respectively, at a current density of 10 mA cm−2. Furthermore, the catalyst demonstrated excellent stability. The designed structure of the catalyst provides theoretical support for the study of Fe-based catalysts in OER and overall water splitting. [Display omitted] • Co,N-FeS x were synthesized by hydrothermal and further annealing in NH 3 atmosphere. • Co and N co-doping is benefit to increase the exposed actives. • FeS/FeS 2 heterojunction can provide the rapid electron transfer. • Co,N-FeS x exhibited desirable OER and overall water splitting activity. [ABSTRACT FROM AUTHOR]

In this work, we have modulated the film growth parameter (post growth annealing) of SnTe-based thin films to enhance the charge carrier transport by controlling the morphology and microstructure. The samples under investigation were prepared by a vacuum tube furnace on a glass substrate using following growth conditions; growth temperature 700 °C, pressure in the tube 180 mTorr, source to substrate distance 7 cm. Grain engineering was performed by annealing the samples at different temperatures (200–500 °C) which was used as a powerful tool to enhance the mobility of charge carriers (7–13 cm2/V-Sec). SEM images demonstrated that a representative sample annealed at 300 °C has a layered structure, therefore the carriers in this sample possessed the highest value of mobility. This encouraging value of carrier mobility resulted in the enhancement of the Seebeck coefficient (7600 μV/K) and electrical conductivity (5S/cm) simultaneously. XRD and Raman spectroscopy measurements were also performed to crystal structure and vibrational modes of annealed SnTe thin films. In conclusion, it is reported that the annealing temperature of 300 °C is supposed to be the optimal value for required grain engineering in order to realize the highest value of the Seebeck coefficient and electrical conductivity. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the effect of strontium (Sr) doping on the thermoelectric properties of thin films made of tin telluride (SnTe). The preparation of Sn 1-x Sr x Te (x = 0, 0.1, 0.2, 0.3, 0.4) films using a straightforward thermal evaporation method and subjected them to post-annealing at 773 K. The surface morphology and crystal structure of the films have been examined by using SEM and XRD, respectively. Our findings indicate that the Seebeck coefficient value increased from 39 to 68 μV/K as the Sr doping concentration increased. This enhancement has been attributed to the energy filtering effect resulting from charge carrier dislocation. However, the electrical conductivity value decreased due to an increase in defect density. The maximum enhancement of the power factor has been observed for x = 0.3, where the value reached 38.9 μWcm−1K−2, which is greater than the pristine sample. Our results conclude that Sr 0.3 doping in Sn 0.7 Te is a valuable addition for thermoelectric applications at room temperature. Additionally, the use of the simple thermal evaporation method for film preparation highlights its potential for large-scale applications. [ABSTRACT FROM AUTHOR]

Higher manganese silicides have evolved as an efficient thermoelectric material because of their exceptional thermoelectric performance at intermediate temperatures. In this work, we report the ultralow-thermal conductivity with improved thermoelectric properties of Mn 1-x Cr x Si 1.8 (x = 0, 0.025, 0.05 and 0.1) prepared by induction melting followed by ball milling and uni-axial induction hot-pressing. Bragg diffraction patterns confirmed that the as-synthesized compound belongs to the Mn 15 Si 26 phase along with the solid solubility of Cr in the HMS lattice. In addition, the backscattered electron micrographs revealed the precipitation of excess Si in the HMS matrix, originating from Si-rich stoichiometry. Furthermore, an elevation in electrical conductivity with increasing Cr content has been observed because of its acceptor dopant behaviour at the Mn site. On the contrary, the Seebeck coefficient decreased upon an increase in Cr content, and bulk MnSi 1.8 has shown the highest Seebeck coefficient of 220 μV/K at 773 K. Impressively, nanostructuring along with the generated point defects as a result of Cr dopant facilitates an intensified phonon scattering at the nanostructured grain boundaries that results in a very low κ total of 0.99 W/mK at 773 K for ball-milled Mn 0.9 Cr 0.1 Si 1.8 , leading to an elevated zT of 0.46 at 773 K. [ABSTRACT FROM AUTHOR]

Concerning environmental issues, including global warming and the reduction of hydrocarbon assets, the utilization of environmentally sustainable energy production is imperative nowadays. In this regard, water electrolysis is considered the most prominent and ecologically sustainable technique for the production of hydrogen. However, owing to its sluggish OER, designing electrode materials with remarkable efficiency becomes crucial for boosting the functioning of water electrolysis. In the present investigation, we successfully developed the SnSe catalyst incorporated into graphitic carbon nitride (g-CN) via a simple hydrothermal approach. The various approaches were used to characterize g-CN/SnSe nanocomposite. Meanwhile, g-CN/SnSe nanocomposite demonstrated exceptional catalytic properties for OER under 1.0 M alkaline electrolyte (KOH), which exhibited low overpotential (241 mV) to obtain ideal j (10 mA cm−2) and an exceptional stability (20 h). It also demonstrated a low onset potential (1.27 V), a significant electrochemical active surface area (ECSA) of 592.5 cm2 and an impressive Tafel value (38 mV dec−1), significantly superior to the pure SnSe nanomaterial. The observed improved performance can be attributed to enhanced morphological properties and significant surface area. The above-reported nanocomposite (g-CN/SnSe) shows great potential for OER and other electrochemical systems because of its numerous active sites, faster electron transfer process, exceptional durability and good electrical conductivity. [ABSTRACT FROM AUTHOR]

Computational experiments were carried out to find a tiny sensor that can detect the Lomustine (LT) drug. The experiments studied how the sensor interacts with regular and aluminum-doped boron nitride sheets (BN-yne and Al-BN). The calculations reveal that the LT medication mainly attaches to the B atom in the BN-yne molecule through its NO group, and the binding energy is −5.2 kcal/mol. Using the LT drug only changes the electronic features of the original BN-yne sheet a little. Replacing a B atom with an Al atom in the –B = N– connection significantly enhances the reactivity and responsiveness of the BN-yne sheet to the LT drug. The electrical conductivity increases because the energy gap of Al-BN decreases from 4.81 to 3.08 eV. Moreover, its work function (Φ) has been significantly reduced from 3.51 to 2.55 eV, which causes an increment in the field emission electron current. Eventually, what is expected is a short recovery time of 3.9 sec for the desorption of LT from the Al-BN surface. As the results suggest, Al-BN can work as perfectly as an electronic sensor to acquire the LT drug. [ABSTRACT FROM AUTHOR]

• Demonstration of a whole-site flushing technique in an MSW landfill. • Use of bromide and water as tracers in landfill. • Verification of dual-porosity behaviour of MSW. • in situ field-scale estimates of block diffusion time. • Examination of different fill-and-draw flushing scenarios. A fill-and-draw flushing test on a landfill cell containing MSW waste was carried out to examine the operational viability of this method for accelerating the flushing of contaminants and landfill stabilisation. During the fill cycle, 800 m3 of water containing the tracer bromide was pumped into the base of a 0.44 ha landfill cell, resulting in the estimated saturation of 9,400 m3 of waste. Abstraction took place in two phases, during which 1,100 m3 of tracer/leachate was recovered. Samples of leachate were analysed for the tracer, electrical conductivity and indigenous solutes chloride and ammonia. Tracer recovery was between 63 and 72 % for bromide. An estimated 227 kg of ammonia and 575 kg of chloride were removed. Test data was used to calibrate a 1D, dual-porosity model involving advection in a mobile zone, and diffusion into 'blocks' of a less mobile zone. The model fitted well to the early time data, whereas later data appears to have been affected by recharge. The results of this trial demonstrate the possibilities of the 'fill-and-draw' concept using the basal leachate drainage system of landfills as a potential accelerated landfill remediation technique. However, modelling results suggest low contaminant removal efficiency. Including a pause between the fill and the draw cycles improves mass removal. [ABSTRACT FROM AUTHOR]

Carbon electrodes are widely used for battery and electrolysis due to wide potential window and chemical stability. The carbon electrode made from carbon material ink using printing process is expected as electrode with low cost and large area. Therefore, we have developed carbon material inks and printed electrode by combining micro-wave treated graphite oxide (MwGO) and screen-printing method. However, the MwGO electrodes exhibited low water resistance. Cellulose nanofiber is mixed into the MwGO ink to improve water resistivity. As a result, increase in water resistance is achieved with maintaining electrical conductivity. [ABSTRACT FROM AUTHOR]

A variety of strategies have been developed to enhance the cycling stability of Si-based anodes in lithium-ion batteries. Although significant progress has been made in enhancing the cycling stability of Si-based anodes, the low initial Coulombic efficiency (ICE) remains a significant challenge to their commercial application. Herein, pitch-based carbon (C) coated Si nanoparticles (NPs) were wrapped by graphene (G) to obtain Si@C/G composite with a small specific surface area of 11.3 m2 g−1, resulting in a high ICE of 91.2% at 500 mA g−1. Moreover, the integrated utilization of graphene and soft carbon derived from the low-cost petroleum pitch strongly promotes the electrical conductivity, structure stability, and reaction kinetics of Si NPs. Consequently, the synthesized Si@C/G with a Si loading of 54.7% delivers large reversible capacity (1191 mAh g−1 at 500 mA g−1), long cycle life over 200 cycles (a capacity retention of 87.1%), and superior rate capability (952 mAh g−1 at 1500 mA g−1). When coupled with a homemade LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode in a full cell, it exhibits a promising cycling stability for 200 cycles. This work presents an innovative approach for the manufacture of Si-based anode materials with commercial application. [ABSTRACT FROM AUTHOR]

[Display omitted] We report on ultra-violet (UV) photodetectors based on BaO nanoparticles by the detailed investigation of band gap and photoluminescence properties. The BaO nanomaterials were fabricated by the modified sol–gel technique. The innovation of co-doping can modulate the photoluminescence or sensing properties by narrowing the band gap related to enhancing the high carrier concentration, higher electronic lifetime, and low carriers recombination. It is investigated that the BaO nanoparticles with co-doping reveals a highly reduced band gap and exceptional photoluminescence properties as compared to the pristine BaO nanoparticles due to hindering carrier,s recombination for Ultra-violet (UV) photodetectors. The optical studies revealed that the addition of co-dopants in BaO host material creates new energy sites, so the band gap declines up to 1.31 eV as compared to that of pristine BaO (1.36 eV). The photoluminescence properties recorded with photoluminescence (PL) spectroscopy were recorded which revealed the decrease in PL intensity due to the hindering of carriers recombination with the addition of co-dopant metal ions. Furthermore, the inclusion of co-dopant metals results in an improvement in electrical conductivity because of a decline in carrier recombination, according to an I-V characteristic study. This factor contributes to enhance the photoluminescence properties of BaO which, in turn, contributes to enhance the sensing capability of the photodetector device. These obtained features modify optoelectronic properties are far superior as compared to that of previously reported literature on BaO nanomaterials, and the synthesized BaO semiconductor material becomes a potential candidate for efficient use in the ultraviolet (UV) photodetectors device applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal selenides are promising anode candidates for sodium ion batteries (SIBs) because of their high theoretical capacity, low cost, and environmental friendship. However, the low rate capability at high current density due to its inherent low electrical conductivity and poor cycle stability caused by inevitable volume variations during cycling frustrate its practical applications. Herein, we have developed a simple metallic-organic frameworks (MOFs)-derived selenide strategy to synthesize a series of heterogeneous bimetallic selenides encapsulated within graphene aerogels (GA) as anodes for SIBs. The bimetallic selenides/GA composites have unique structural characteristics that can shorten the migration path for Na+/electrons and accommodate the volume variations via additional void space during cycling. The built-in electric fields induced at the heterointerfaces can greatly reduce the activation energy for rapid charge transfer kinetics and promote the diffusion of Na+/electrons. GA is also beneficial for accommodating the volume variations during cycling and improving conductivity. As an advanced anode for SIBs, the MoSe2-Cu1.82Se@GA with a special porous octahedron can deliver the highest capacity of 444.8 mAh/g at a high rate of 1 A/g even after 1000 cycles among the bimetallic selenides/GA composites. [ABSTRACT FROM AUTHOR]

Recent research has emphasized the investigation of BiFeO 3 –BaTiO 3 (BFO–BT) piezoelectric ceramics due to their elevated Curie temperature. Nevertheless, the substantial electrical conductivity of these ceramics poses practical challenges. This study evaluates the influence of post-annealing and manganese (Mn) doping on the conductivity, dielectric behavior, and ferroelectric properties of (1-x)BFO–xBT ceramics with a morphotropic phase boundary composition (x = 0.33). The results demonstrate that the conductivity of the ceramics in the as-sintered state is affected by Maxwell-Wagner effects arising from variations in conductivity at grain boundaries. Annealing under specific atmospheres indicates that the electrical conductivity is of the p-type, potentially associated with Fe4+ defects. Furthermore, annealing in a carefully controlled atmosphere or the introduction of Mn doping significantly alleviate these effects, leading to an enhancement in domain switching characteristics. The insights garnered from this investigation regarding annealing and doping have the potential to advance lead-free BFO–BT piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Doped LaCrO 3 perovskites hold promise as robust materials for electrical interconnects and sensor applications in harsh environments. In this work, we investigated the high-temperature behavior of La 1–x Sr x CrO 3 , La 1–x Ca x CrO 3 and La 0.8 Sr 0.2 Cr 1-x Mn x O 3 (0.1 ≤ x ≤ 0.4) through a combination of computational modeling and physical characterization up to 1500 °C. Crystalline structural properties were determined and compared with ab-initio calculations, which demonstrated excellent agreement with experimental findings. High-temperature electrical conductivity measurements were performed under different atmospheres. Calcium and strontium/manganese co-doped lanthanum chromites exhibited typical semiconductor exponential trends and conductivity showed proportional correlation with substitutions levels up to 30%. The DFT modelling was completed up to 1500 °C, including low and high temperature chromite phases and oxygen vacancies insertion. Calculations were correlated with experimental electrical properties. This work expands the understanding of doped lanthanum chromites and paves the way for the development of materials suitable for demanding high-temperature applications. [ABSTRACT FROM AUTHOR]

Synthesis of unique morphologies in photocatalytic materials, coupled with utilization of wide-spectrum solar energy through rare earth doping, holds significant promise to maximize the potential of photocatalysts. Herein in, cube-like Holmium (Ho) doped Bi 5 Nb 3 O 15 was synthesized by the hydrothermal method and integrated with reduced graphene oxide (rGO) sheets. As synthesized Ho–Bi 5 Nb 3 O 15 @rGO composite along its analogs i.e., Bi 5 Nb 3 O 15 and Ho–Bi 5 Nb 3 O 15 was characterized by XRD, SEM, FT-IR, TGA, I–V, EIS, Mott-Schottky and photo-current measurements. Phase studies showed that crystallite size for Bi 5 Nb 3 O 15 , Ho–Bi 5 Nb 3 O 15 , and Ho–Bi 5 Nb 3 O 15 @rGO was 27.4, 25.5, and 13.5 nm, respectively. Optical analysis exhibited a reduction in the band gap in consequent to Ho doping from 2.54 to 2.19 eV for Ho–Bi 5 Nb 3 O 15. Conductivity and photo-current measurements showed a remarkable increase in both electrical conductivity and photo-response of Ho–Bi 5 Nb 3 O 15 upon its incorporation into rGO matrix, reaching maximum values of 1.72 × 10−2 S/m and 0.66 μA, respectively. The enhanced photocatalytic activity of Ho–Bi 5 Nb 3 O 15 @rGO was ensured through the outstanding photo-degradation efficiency (96.5 %) against crystal violet (CV), greater than Bi 5 Nb 3 O 15 (49 %) and Ho–Bi 5 Nb 3 O 15 (63.4 %). Additionally, Ho–Bi 5 Nb 3 O 15 @rGO showed sufficient potential towards the degradation of acetylsalicylic acid (ASA) with 79.1 % photo-degradation. This elevated photocatalytic activity of Ho–Bi 5 Nb 3 O 15 @rGO is believed to be contributed by the collaborative outcomes aroused from the Ho-doping and heterojunction fabrication among cubical Ho–Bi 5 Nb 3 O 15 and rGO sheets. Hence, our work proposes an efficient strategy for the development of innovative photolytic materials for sustainable wastewater remediation. [ABSTRACT FROM AUTHOR]

The influence of the heterogeneous interface is critical for the catalytic activity of the oxygen reduction reaction (ORR). This study demonstrates an enhancement of the electrocatalytic activity of the SrFe 0.9 Nb 0.1 O 3-δ (SFN113) electrode through the construction of a SrFe 0.9 Nb 0.1 O 3-δ -Sr 3 Fe 1.8 Nb 0.2 O 7-δ (SFN113-SFN327) heterogeneous interface. By coating varying amounts of Sr(NO 3) 2 (0.1 g, 0.2 g and 0.3 g) on SFN113 (1 g), SFN113/327 composite electrodes with different amounts of triple conducting oxide SFN327 are in-situ synthesized by high temperature calcination. Electrical Conductivity Relaxation (ECR) tests show that SFN327 has superior oxygen surface exchange performance compared to SFN113, especially at lower temperatures. At 550 °C, the oxygen surface exchange parameter of SFN327 is 4.23 times higher than that of SFN113. Symmetric cell tests with SFN113/327||BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ (BCZYYb)||SFN113/327 configuration and single cell tests with Ni-BCZYYb||BCZYYb||SFN113/327 configuration indicate that the SFN113/327 composite electrode with a mass ratio of 1:0.2 displays the best electrocatalytic performance, achieving a power output of 502 mW cm−2 at 700 °C. The work not only in-situ synthesizes the SFN113/327 triple conducting composite electrode, but also introduces a novel method for developing proton conducting electrode materials. [ABSTRACT FROM AUTHOR]