MRS Communications最新文献

Abstract

This study introduces a method to create porous carbon structures with intricate internal voids. 3D-printed PLA acts as an internal sacrificial template, combined with carbonized whey powder as the porous carbon matrix. Sintering whey powder at 150°C yields solid pieces that, upon carbonization, result in highly porous carbon objects while maintaining the original mold shape. Temperature control ensures successful whey powder sintering before PLA melting. The use of PLA sacrificial templates, along with whey carbonization, allows for developing devices with finely tailored internal voids, as demonstrated through a double Archimedean spiral reactor with porous carbon walls.

Abstract

We present the analytic workflow to understand the temperature and illumination-intensity-dependent recombination of the photoinduced charge carriers in organic–inorganic hybrid perovskite solar cells based on methylammonium lead iodide (CH₃NH₃PbI₃) thin films. The temperature-dependent, open-circuit voltage analysis reveals that the recombination of photoinduced charge carriers predominantly occurs at our PEDOT:PSS/CH₃NH₃PbI₃ interface as well as in the depletion region. Taking into account the structural phase transition in CH₃NH₃PbI₃ films, as confirmed using temperature-dependent x-ray diffraction spectra and dielectric constant measurements, the illumination-dependent short-circuit current and open-circuit voltage analysis shows both bimolecular and trap-assisted recombination is dominant in our solution-processed perovskite solar cells.

While efforts have been made to optimize organic semiconducting materials to achieve low-power-consumption organic field-effect transistors (OFETs), it is important to note that the choice of gate dielectric materials is equally critical. In general, a high-k polymer dielectric material is highly preferred for low-power-consumption OFETs. In this perspective, we highlight several newly emerged strategies for high dielectric constant polymer dielectrics. By exploiting the recent advances in molecular modulation and morphology control, these new strategies enable remarkably high dielectric constant up to 25–30 for polymer dielectrics, while still maintaining dielectric losses below 0.01 at 1 kHz. We further analyze the advantages and disadvantages of these strategies and propose four design principles—side-chain dipole, rigid free volume, self-assembly, and thermosets—for future polymer gate dielectrics in OFETs.

Graphical abstract

This study examines the effects of Mn²⁺ doping on the microstructure, morphology, and thermoresistive properties of the Zn_x-1Mn_xO system (x = 0.8, 0.15 mol), synthesized via a combustion reaction. After uniaxial pressing (191 MPa) and sintering (1373 K), the samples exhibited NTC thermistor characteristics without a second phase. The decrease in the energy gap to 2.9 eV (Mn08) and 2.69 eV (Mn15), along with average particle sizes of 8.79 µm and 2.91 µm, respectively. The parameters α, β, A, B, C, and SF highlight the influence of Mn²⁺ doping on the properties of these materials, with potential applications in NTC thermistor devices.

Graphical abstract

A series of titanium dioxide nanotubes were synthesized via a hydrothermal method. By varying the preparation conditions, nanotubes with different morphologies or textural properties were produced. Various characterization techniques were used to clarify the various features of the as-prepared nanotubes. Samples with surface areas ranging between 200 and 230 m²/g in specific surface area exhibit the maximum photocatalytic activity in the degradation of formic acid. Detailed analysis of the structural characteristics emphasizes the complex role played by surface structural defects in the tuning of their photocatalytic performance helping in this way to achieve optimal activity in photooxidation.

Graphical abstract

An alloy based on the Laves phase, which hydrogenated at room temperature, and magnesium powder were used to create the composite material. Using the method of hydrogen dispersion, the alloy was crushed into a powder with a size of 30 μm. Composite materials were obtained by mixing magnesium with a size of 100 μm and the resulting powders from the alloy for 8 h, followed by pressing. This made it possible to obtain a new type of materials for hydrogen batteries, since they cannot be produced by the traditional casting method, because they do not have mutual solubility.

Graphical abstract

Bridgman grown CsPbBr₃ single crystals have demonstrated γ-ray spectra with a high resolution, making them a highly promising competitor for the current benchmark room-temperature radiation detector Cd_1−xZn_xTe. However, CsPbBr₃ crystal growth is a very slow process that oftentimes results in cracked ingots due to phase transitions from cubic to orthorhombic crystal systems. In this report, we demonstrate the stabilization of a room-temperature cubic phase in Cs(Pb_1−xSn_x)(Br_3−yCl_y) solid solutions to overcome this issue. Cs(Pb_0.75Sn_0.25)(Br_1.00Cl_2.00) was identified as the most promising composition and grown as a crack-free ingot using Bridgman growth in around one week.

Graphical abstract

This paper presents a groundbreaking strategy for optimizing composite laminate structures by integrating finite element modeling with a specialized multi-layer neural network. The neural network is trained on precise ground truth data obtained from rigorous finite element simulations, allowing it to discern intricate correlations among layer orientations, boundary conditions, and optimized designs. Tailored to the nuances of laminar composite optimization, the developed neural network emerges as a potent predictive tool, providing deep insights into the intricate interdependencies of design parameters. The study's findings hold immense promise for advancing materials design and structural engineering, highlighting the transformative potential of combining computational intelligence with traditional modeling approaches.

Graphical abstract

Abstract

Hybrids of carbon nanotube and metals have been regarded as promising candidate for flexible circuit, where thermal stability of nanograined metals is a challenging issue. In this study, we find thermal stability of Cu layer in CNT–Cu hybrids can be improved by coating Al₂O₃ layer. As for CNT–Cu hybrids, Cu nanograins are agglomerated during 673 K annealing. In contrast, the agglomeration of CNT–Cu hybrids can be suppressed after coating Al₂O₃ layer, and exhibit a thickness-dependent thermal stability after annealing at higher temperature. The underlying mechanism might be the compressive stress applied by Al₂O₃ coatings and inhibited diffusion along Cu/Al₂O₃ interfaces.