Materials Letters: X最新文献

Two-dimensional (2D) layered black phosphorus (BP), with a direct band gap and high carrier mobility, has shown great potential for next generation electronics and optoelectronics. However, how to prepare a large-area 2D material film is still a big problem for realizing its practical applications. Herein, an improved one-step solution-processable method is put forward to solving this problem to get uniform and large-area BP film. Our results show that the designed electrodes can be fully covered by BP flakes and the corresponding FET reveals relatively high performance. Our study opens a new avenue in fabricating large-area ultra-thin BP films.

We have developed a method for designing polymer and graphene nanoplatelet (GNP) composites that show high dielectric constants over a wide range of GNP contents. GNPs are dispersed in the composites through plasma-surface modification and aligned by applying an electric field (EF). This creates a large number of microcapacitor structures of GNPs separated by the polymer. The maximum dielectric constant of the sample to which the EF is applied is approximately twice that of the sample to which the EF is not applied. Furthermore, the maximum dielectric constants of the samples with plasma-surface modified GNPs are higher than those of the samples with unmodified GNPs. The composites show high dielectric constants (∼500 at 100 Hz) over a wide range of GNP contents (6 ∼ 10 wt%) while maintaining mechanical flexibility (Young’s modulus:12 ± 4 MPa).

The two-dimensional bi-layer MoS₂ is less investigated as compared to monolayer and few-layer (4–6 layers) MoS₂ for fundamental aspects and applications such as photodetectors, transistors, etc. In the present work, we prepare triangular-shaped bi-layer MoS₂ over SiO₂/Si substrate via chemical vapour deposition (CVD) technique for surface enhanced Raman scattering (SERS) based detection of Rhodamine 6G (R6G). We perform density functional theory calculations and spectroscopy studies to investigate the semiconducting feature of bi-layer MoS₂. We demonstrate the nanomolar concentration (10^-9 M) limit for R6G detection at room temperature using pristine bi-layer MoS₂ as SERS substrate. Further, we also examine the cryogenic response of the SERS detection of R6G with bi-layer MoS₂ for the first time. The high detection limit of CVD-grown bi-layer MoS₂ is ascribed to the charge transfer enabled via vibronic coupling between MoS₂ and R6G molecules. This study paves the way for cryogenic-based SERS sensing.

A series of Eu³⁺-doped of CaAlSiO₄F red-emitting phosphors for different concentrations were successfully synthesized by using high temperature solid state diffusion method. The phase identification of the prepared phosphor was recorded using x-ray diffraction (XRD). In PL study, the emission peak of prepared phosphor was located at 595 nm and 618 nm due to ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions at excitation of 257 nm, 395 nm and 465 nm. Morphological behaviour of prepared sample was analyzed by using scanning electron microscope (SEM). Commission de l'Eclairage chromaticity (CIE) coordinates were analyzed based on the PL emission spectra of the series CaAlSiO₄F: Eu³⁺ activated phosphor. Therefore, these possible outcomes indicate that the CaAlSiO₄F: Eu³⁺ products have great potential applications in solid state lighting industry.

Numerous antioxidants were extensively found in many plants at different levels which are associated with the therapeutic importance of medicinal plants. The therapeutic impact of the traditional plants Melia dubia's leaves was previously thoroughly explored. The current investigation aimed to examine the biological application of natural antioxidants in the bark extract of Melia Dubia and their effect on breast cancer cells by MTT test. Preliminary phytochemical analysis of six extracts of Melia dubia bark was tested. Anthocyanine compound MDB-1 (isolated compound) is separated from the potential extract (methanol) by combined chromatography methods. On In-vitro analysis, the IC₅₀ value of MDB-1 on the MCF7 cell line is 18.32 µg/ml which exhibits a cytotoxicity effect on the breast cancer cells. The isolated compound MDB-1 will be further used to develop drug formulations to overcome world challenges in cancer treatment.

Substrates play an important role in influencing the physical properties of any thin film for different applications. The current work provides a brief overview of various substrate effects on CdSe thin film. XRD pattern reveals that CdSe films on FTO are more crystalline. The optical spectrum of CdSe films is highly affected by different substrates. The electrical properties of all samples were investigated using Hall and I-V measurements. CdSe films on FTO show higher electrical conductivity than others.

Electromechanically active nano/microfibers are promising components of sensors and actuators; however, piezoelectric polymers are normally expensive. To address this issue, this study examined the geometrical and electrostatic densities of an inexpensive highly sparse as-electrospun atactic polystyrene microfiber mat. The densities of porous individual fibers and the highly sparse fiber mat were experimentally determined to be 0.88 and 0.051 g cm⁻³, respectively, with corresponding material filling ratios of 80 % and 4.7 %, respectively. A high theoretical surface charge density of approximately 1.4 × 10⁻³ C m⁻² was determined for the fiber mat after excluding air spaces in both individual fibers and the mat. These findings provide a pathway to outstanding electrets that are ultra-lightweight and have high charge densities.

Artificial red lights of good quality are essential for indoor plant growth as it has a wide spectrum effects on photosynthesis rate and photomorphogenic processes of organic plant growth cycle. In present work we report on Eu³⁺ doped Bi₄Si₃O₁₂ (BSO) phosphor for spectroscopic implication in smart plant grow LEDs. Eu³⁺ activated series of Bi₄Si₃O₁₂ phosphor have been prepared via traditional solid-state reaction method. Crystal structure and phase formation characterization is determined by using X-ray diffraction (XRD). Photoluminescence spectra of prepared phosphor shows broad excitation spectra ranging from 200 to 530 nm. The optimal Eu³⁺ doping concentration observed at 3 mol%. Emission spectra observed under the excitation of 270 nm shows broad emission band at 469 nm along with other characteristic peak at 500 nm-710 nm. Observed emission peaks at 622 nm, 656 nm and 702 nm were chosen opt for plant grow lights. The phytochrome PFR absorption spectra of plants matches well with the emission band of our Eu³⁺ doped BSO phosphor and can be considered as a viable choice for solid state lighting and plant grow light LEDs.

Wet chemical technique was used for the Synthesis of Sm³⁺ doped Ca₁₀(PO₄)₆Cl₂ phosphor. The phase purity was analyzed by using X-Ray diffraction (XRD), which show that the synthesized phosphor was well matched with standard PDF file. Photoluminescence properties of Ca₁₀(PO₄)₆Cl₂:Sm³⁺ phosphor shows emission peak at 563 nm, 607 nm & 646 nm corresponding to ⁴G_5/2→(⁶H_5/2, ⁶H_7/2, ⁶H_9/2) transition of Sm³⁺ ions. The emission spectra of Ca₁₀(PO₄)₆Cl₂:Sm³⁺ phosphor was very intense and sharp. As per the current investigation of synthesized phosphor, it indicate that it is a used in solid state lighting devices and display application.