Materials Advances最新文献

Here we present a nanopatterning strategy utilising thermal scanning probe lithography (t-SPL) for the precise organisation of DNA origami into nanoarrays. The aim of this approach is to demonstrate control in the fabrication of nanoarray platforms exhibiting single-molecule accuracy. Combining the inherent programmability of DNA origami structures with t-SPL nanopatterning, we demonstrated the controlled immobilisation on surfaces of functionalised DNA origami – as proof of concept we employed gold nanoparticles (AuNPs) and quantum dots (QDs) – at predefined positions and in nanoarray configurations. This method holds great potential for the construction of hetero-functionalised biomolecular nanoarrays with single-molecule control, with applications in bionanotechnology and (nano)materials science.

This work presents a detailed comparative study on the effects of functional groups on engineered PDI (perylene diimide) compounds for pressure and breath sensing applications using experimental findings and density functional theory (DFT)-based theoretical calculations. The results demonstrate that the deposition of N-substituted perylene-3,4-dicarboxylic acid imide derivatives (PDI-1, PDI-2, PDI-3, and PDI-4) with different functional groups (3-aminopentane, 2,5-di-tert-butylaniline, 1-phenylethylamine, etc.) on the paper substrate forms a moderately conducting percolating molecular network with enhanced pressure and breath-sensing performances. The determined pressure sensitivity value for PDI-1 was 0.315 kPa⁻¹, for PDI-2 was 1.266 kPa⁻¹, for PDI-3 was 0.749 kPa⁻¹, and for PDI-4 was 2.120 kPa⁻¹. Among all the fabricated PDI-based pressure sensors, PDI-4 displayed maximum sensitivity owing to the inherent asymmetric nature of the compound with two different terminal substituents. The sensor displayed a steady response of up to ∼8000–10 000 cycles, confirming the mechanical sturdiness of fabricated PDI-based pressure sensors. The DFT-based theoretical analysis offers detailed insight into the transduction mechanism of pressure and breath sensing for different PDI molecules, wherein it can be surmised that both the structural configuration and electronic properties of PDI-4 (PDI-1) are suitable (undesirable) to ensure a large increase in intermolecular tunneling components and, thereby, in the overall conductivity of the percolating network under applied pressure. Hence, PDI-4 (PDI-1) is the most (least) favorable PDI molecule for pressure sensing applications. In contrast, a moderate response can be expected in PDI-2 and PDI-3 during pressure sensing as two competing factors influence the overall efficacy of transduction in these cases.

Our present study developed high-performance organic photodetectors (OPDs) with broad-spectrum capabilities utilizing a thiazolo[5,4-d]thiazole containing a high-mobility conjugated polymer P-TZTZ. The low bandgap polymer with 2D nanosheet morphology is synthesized by an easy condensation reaction between dithiooxamide and terephthalaldehyde. Based on the used substrate (Si-wafer and PET substrate), two variants of the proposed photodetectors were fabricated. Both variants of the fabricated photodetectors (PDs) demonstrated comparable photodetection capabilities in a broad region from 400 to 1000 nm. Under the presence of a broadband white light source, the peak photo-to-dark current ratio (PDCR) values for the PD fabricated on Si-substrate (PD1) are calculated to be 42.58 and 5.68 at the bias voltage (V_B) of −0.1 and +1.0 V, respectively. Similarly, the PD fabricated on ITO-coated PET substrate (PD2) under the influence of a broadband white light source offered PDCR values of 8.65 and 7.25 at a V_B of −4 V and +4 V, respectively. Experimental findings indicate that the fabricated PD1 achieves a peak responsivity of 2.12 A W⁻¹ at 410 nm with peak external quantum efficiency (EQE) values of 6.41% and 4.32% at 410 and 530 nm, respectively. The specific detectivity (D) values are estimated to be 4.42 × 10¹³ Jones at 410 nm and 3.71 × 10¹³ Jones at 530 nm. Similarly, the fabricated PD2 achieves the peak responsivity, external quantum efficiency, and specific detectivity values of 1.98 A W⁻¹, 5.9% and 1.71 × 10¹³ Jones at 410 nm, respectively. Transient performance analysis revealed that the P-TZTZ-based flexible PD exhibited rise and fall times of 180 ms and 100 ms, respectively. The high responsivity, detectivity, and millisecond-order switching time in rigid and flexible P-TZTZ-based PDs demonstrate the versatility and potential for diverse applications covering from rigid to flexible electronics.

Ni–Zn-based ferrites (NZFO) need to possess the ideal ratio of dielectric and magnetic characteristics for uses involving electromagnetic fields. Consequently, the NZFO system has been modified by Ti⁴⁺ substitution at Fe³⁺ producing Ni_0.5Zn_0.5Ti_xFe_2−xO₄ (x = 0.00, 0.02, 0.04, 0.06, 0.08 and 0.10) and a conventional sol–gel process was followed for the synthesis. The structure of the synthesized samples was evaluated from the X-ray diffraction (XRD) patterns. Fourier transform infrared (FTIR) measurement provided information on chemical interaction with thermodynamic conditions. In addition, the grain sizes were obtained from scanning electron microscopy (SEM). Furthermore, the studied samples exhibit a notable light absorption in the visible spectrum with band gaps between 3.8 and 4.8 eV. The magneto-dielectric properties were analyzed by field (H) dependent magnetization (M), frequency-dependent permeability (μ), and permittivity (ε) measurements. Ti⁴⁺ substitution in NZFO led to a decrease in magnetic saturation (M_s) and μ while the values of creased and improved the mismatching impedance (Z/η₀ = (μ′/ε′)^1/2). The lowest value of M_s (14 emu g⁻¹) is achieved for the sample with x = 0.1 for which μ is also the lowest. Finally, a stable value of Z/η₀ (∼4.0) has been obtained for the x = 0.10 sample over a wide range of frequencies (1–10 MHz), making it suitable as a miniaturizing device material in this frequency range.

Edible oils are prone to spoilage through aerial oxidation, leading to a reduction in their shelf life. In this study, we developed a nanocomposite biopolymer film designed for packaging edible oils. To enhance the antioxidant properties of the film, an extract from Moringa oleifera plants was obtained through solvent extraction and incorporated into the biopolymer. This infusion of plant extract bestowed antioxidant characteristics upon the resulting material. It was determined by GC–MS that Moringa oleifera water extract contains 9-octadecenamide, (Z)-(an Oleamide), which provides antioxidant properties. Additionally, cellulose nanofibers (CNF) were extracted from Terminalia arjuna plant fruits using the acid hydrolysis method. These CNFs were further introduced into the biopolymer to reinforce its mechanical properties of the biopolymer. The stability of the biopolymer film was evaluated in various edible oils (viz. mustard oil, olive oil, soybean oil, and sunflower oil), and the optimized nanocomposite film exhibited a tensile strength of approximately 44 MPa in the dry state. The antioxidant capacity was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azina-bis(3-ethylbenzothiazoline-6-sulfonic acid)) free radical scavenging assays. The plant extract-based biopolymer nanocomposite film, specifically the (0.25CNF-4WME-SA) formulation, demonstrated the highest antioxidant activity, reaching 60.55% and 41.33% against ABTS and DPPH, respectively. The practical effectiveness of the 0.25CNF-4WME-SA film was further demonstrated through its application in packaging edible oil, showcasing its ability to scavenge free radicals generated during the storage of edible oil. The cytotoxicity of the fabricated film was evaluated using CC1 hepatocyte cells as an in vitro model. The developed nanocomposite material, incorporating plant extract, holds promise as an active packaging material for edible oils.

Carbon dot-based radiocontrast agents have recently sparked the interest of researchers owing to their better contrasting capabilities, simple synthesis protocols, high colloidal stability, and good biocompatibility. In this study, we propose for the first time the synthesis of iodine-doped carbon dots (I-CDs) using low-cost reagents such as citric acid (C₆H₈O₇), urea (CH₄N₂O) and potassium iodide (KI). The as-prepared I-CDs demonstrated excellent colloidal stability (with a zeta potential value of −64.7 mV), excitation-dependent fluorescent properties (with a maximum quantum yield of ∼8.9%), and a mean iodine concentration of ∼4.67 wt%. Notably, the as-prepared I-CDs displayed greater X-ray attenuation efficiency (42.87 HU mL mg⁻¹) as compared to the commercially employed iopromide radiocontrast agent (30.98 HU mL mg⁻¹). Furthermore, ATPase activity, cytotoxicity analysis with HeLa, NHDF, HEK293, and A549 cell lines, and live-cell imaging experiments of the Drosophila neuroblasts in intact brain lobes suggested high biocompatibility and nontoxicity of the prepared I-CDs. Overall, biocompatible and low-cost I-CDs show great promise as bifunctional radiocontrast and fluorescent agents for biomedical applications.

Efficiency improvement of heterogeneous silicon thin-film solar cells (SiTFSCs) remains challenging. Thus, single-walled carbon nanotube (SWCNT) and zinc oxide nanostructures (ZnO NCs) were integrated into Si thin films using the spray-spin coating approach to realize such solar cells. The effect of various annealing temperatures (100–175 °C) on the solar cells’ efficiency, structure, morphology, and absorbance was assessed. X-ray diffraction analysis confirmed the existence of highly crystalline wurtzite and hexagonal structures corresponding to ZnO and graphite with maximum nanocrystallite sizes of 51.92 nm. Scanning electron microscopy images of the samples showed uniform surface morphology without any aggregation. In addition, with the increase of the annealing temperature from 100 to 175 °C, the efficiency, porosity, optical absorbance bands, and band gap energy of the films were increased from 17.0–18.6%, 70–74.8%, 246–326 nm, and 2.0–2.5 eV, respectively. It was asserted that by controlling the annealing temperature, the overall performance of the proposed SWCNT/ZnO NC-integrated SiTFSC can be enhanced, contributing to the further advancement of high-performance Si-based photovoltaics.

Dialkylamido compounds, such as tris-dimethylamido aluminum (TDMAA, Al(NMe₂)₃) and tetrakis-dimethylamido titanium (TDMAT, Ti(NMe₂)₄) are interesting precursors for depositing nitrides using atomic layer deposition (ALD) due to their high volatility and reactivity at low temperatures. In this study, we explored surface chemistry using mass spectrometry and discovered that the surface mechanisms involved β-hydride elimination and ligand decomposition, as well as transamination and hydrogenation reactions which facilitate ligand exchange. This is mainly based on the –N(Me)₂ and HN(Me)₂ detected during both TDMAA and NH₃ pulses, and CH₄ signals detected during the NH₃ pulse stage. The expected reductive elimination of the two dimethylamido ligands, via a direct nitrogen–nitrogen coupling reaction was not observed, suggesting that it is less thermodynamically favorable compared to reduction by NH₃. Arrhenius analysis between 150 and 300 °C found activation energies (E_a) = 27–30 kJ mol⁻¹ and pre-exponential factors (A) = 3–5 s⁻¹ for the reaction between TDMAA and NH₃.

Eumelanin is a black-brown biopigment that provides photoprotection and pigmentation in mammals, insects, and invertebrates. It can be obtained by oxidative polymerisation of 5,6-dihydroxyindole (DHI) and its 2-carboxylic acid (DHICA). Due to its unique physical and chemical properties and its biocompatibility, eumelanin is a promising biomaterial for applications in energy storage, biomedicine, and sensing. However, poor solubility in water and lack of sustainable and low-cost sources of eumelanin have so far limited the full exploitation of this biomaterial. Insect farming is rapidly emerging as an alternative source of eumelanin. Unlike other types of eumelanin, BSF eumelanin, which is extracted from the exoskeleton of the black soldier fly (BSF, Hermetia illucens), is water-dispersible; however, its fundamental chemical properties are not completely understood. Here, we report the characterisation of BSF eumelanin using various spectroscopy techniques. Contrary to what is known about other insect eumelanins, which are believed to contain exclusively DHI, our results indicate that BSF eumelanin may contain both DHI and DHICA moieties. We discuss the potential reasons for this discrepancy.

Polynuclear and mononuclear molybdenum(VI) complexes, coordinated with water or methanol, were synthesized using acyl-hydrazone ligands, derived from the reactions of 2-hydroxy-3-methoxybenzaldehyde with formic – (H₂L¹) or acetic acid hydrazide (H₂L²). Characterization of the complexes was conducted utilizing advanced spectroscopic techniques and elemental analysis. Crystal and molecular structures of ligand H₂L², and complexes [MoO₂(L¹)(H₂O)], [MoO₂(L²)(MeOH)], together with (Hpy)₂Mo₈O₂₆ were determined by single crystal X-ray diffraction. The thermogravimetry provided insights into the thermal stability and decomposition patterns of the complexes. In situ solid-state impedance spectroscopy was employed, revealing correlations between the electrical properties and the thermal and structural transformations of Mo complexes. This multifaceted approach enabled a profound understanding of the interplay between structure, thermal behaviour, and electrical characteristics. The polynuclear complex [MoO₂(L¹)]_n exhibited remarkable conductivity, achieving values up to 10⁻⁸ (Ω cm)⁻¹ at room temperature. This performance, compared to previously reported vanadium-based analogues, highlights its considerable potential for integration into electronic device manufacturing. Additionally, the catalytic efficiency of these newly synthesized molybdenum complexes was evaluated in linalool oxidation, alongside previously reported vanadium compounds, further demonstrating their promising applications in catalysis.