Journals
2025 EN
Ibrahim Ahmed A. S. · Bochmann Arne · Löhnert Romy
+1 more
Abstract In transverse thermoelectric generators (TTEGs), comprising an artificially anisotropic material formed by a layered and tilted structure of two materials, the induced thermoelectric voltage is generated perpendicular to the applied temperature gradient. The performance of TTEGs composed of alternate layers of La 1.99 Sr 0.01 CuO 4 (LSCO) and silver (Ag), tilted at an angle φ , with metal‐to‐ceramic thickness ratio ν t , is investigated. Improvement in performance is achieved by optimizing the internal geometry parameters, φ and ν t of the tilted layered structure. The transverse power factor PF tr and figure‐of‐merit Z tr T of the artificially tilted material composite are analytically calculated and presented in color contours. Experimentally, a power output P out of 14.5 mW at Δ T = 140 K is measured for a TTEG with φ = 66°, compared to 2.8 mW and 11 mW for generators with φ of 20° and 45°, respectively. Moreover, TTEGs with different values of ν t are prepared. Furthermore, transverse multilayer thermoelectric generators (TMLTEG) with output power of 14.3 mW at Δ T = 225 K are fabricated utilizing the ceramic multilayer technology. It is demonstrated that the transverse thermoelectric effect using an artificial anisotropic material consisting of ceramic and metal can be explored for autonomous thermoelectric energy generation for low‐power applications.
Journals
2025 EN
Mekseriwattana Wid · Silvestri Niccolò · Brescia Rosaria
+5 more
Abstract Iron oxide nanocubes (IONCs) are among the most promising materials in magnetic hyperthermia (MHT) for tumor therapy as they can efficiently convert magnetic energy into heat under alternating magnetic field (AMF). Conventional IONCs syntheses are based on thermal decomposition methods, limited by the long reaction time (hours) and milligram‐scale production; while, solvothermal methods produce gram‐scale amount of high quality IONCs, but, reaction times are of the orders of hours. In this work, a microwave‐assisted route to shape‐control IONCs in which the reaction time is reduced to minutes while achieving a high iron conversion yield up to 80% is reported. The size of the IONCs (range 13–30 nm) is coarse‐tuned by adjusting the amount of benzaldehyde ligand, while fine‐size tuning is achieved by changing temperature and minute‐reaction time. IONCs exhibit superparamagnetic behavior at 298 K with saturation magnetization over 80 emu g IONC −1 and possess high specific absorption rate values (SAR) up to 400 W g Fe −1 at clinical AMF conditions. These results mark a milestone for rapid synthesis of IONCs at high yield conversion of well‐defined size and shape nanocubes with benchmark MHT heat performance while using a fast route, with limited energy consumption which makes this method greener and cheaper than previous ones.
Journals
2025 EN
Lushaj Edlind · Shifa Tofik Ahmed · Ibrahim Kassa Belay
+8 more
Abstract Oxygen evolution reaction (OER) is a key step affecting the large‐scale hydrogen fuel production from water splitting due to its slow kinetics. Despite numerous OER electrocatalysts, there is still a need for cheap, robust, and efficient catalysts. Here, a new facile protocol aimed at synthesizing composite nanostructures is described in which the characteristics of Prussian Blue Analogues (PBAs), namely nickel hexacyanoferrate (Ni‐HCF), and trigonal selenium ( t‐ Se) are merged. A novel surface‐structure modulation strategy is proposed that allows the PBA Ni‐HCF to develop a new morphology while integrating t‐ Se. Increasing selenization rates influence the shape, size, composition, and electronic and functional properties of the materials with a cube‐to‐sphere transition at high t‐ Se content. The catalyst with the second highest t‐ Se content exhibits an overpotential of 180 mV, achieving a current density of 10 mA cm −2 in 1 m KOH with a Tafel slope of 59.9 mV dec −1 . This performance, attributable to the synergistic effect of PBA‐based nanomaterial and trigonal selenium, rivals the best results described in the literature. The study suggests a simplified route for developing effective OER electrodes using economically affordable and abundant materials like Ni, Fe, and Se in Ni‐HCF/ t‐ Se, potentially replacing expensive Ru‐ and Ir‐based commercial catalysts.
Journals
2025 EN
Qin Weixia · Cui Junjie · Li Yan
+9 more
Abstract The combination of photodynamic therapy (PDT) with sonodynamic therapy (SDT) can compensate for shortcomings of PDT, such as the limited tissue penetration depth or low efficiency of reactive oxygen species (ROS) generation of SDT, but it is still a great challenge to design and synthesize an ideal photo‐/sono‐sensitizer with a satisfactory targeting capability and biosafety. Herein, a novel type of carbon dots (CDs) containing morpholino surface group and the photo‐/sono‐sensitive core is synthesized by using levofloxacin and methylene blue as precursors via a hydrothermal synthesis. The as‐synthesized CDs show a highly efficient generation of singlet oxygen ( 1 O 2 ) under a red laser irradiation while producing 1 O 2 and hydroxyl radical (·OH) under a low‐intensity pulsed US stimulation, which leads to a remarkably enhanced ROS production yield in combined PDT and SDT of breast tumor. In the meantime, the CDs demonstrate a lysosome‐targeting ability in breast tumor cells, which causes lysosomal damage and release of acid phosphatase, resulting in massive apoptosis of cells and more than 90% of cell death. Further, in vivo experimental results confirm the effect of the CDs to inhibit or even eliminate the tumor growth of 4T1 tumor‐bearing mice after the combined PDT and SDT.
Journals
2025 EN
Kayaci Nilgun · Kiremitler Nuri Burak · Deneme İbrahim
+5 more
Abstract The prevention of counterfeiting and the assurance of object authenticity require stochastic encoding schemes based on physically unclonable functions (PUFs). There is an urgent need for exceptionally large encoding capacities and multi‐level responses within a molecularly defined, single‐material system. Herein, a novel stochastic orientational encoding approach is demonstrated using a facile ambient‐atmosphere solution processing of a molecular thin film based on the rod‐shaped oligo(p‐phenyleneethynylene) (OPE) π ‐architecture. The nanoscopic film, derived from the small molecule 2EHO‐CF 3 PyPE with donor, acceptor, and π ‐spacer building units, is designed for energetically favorable uniaxial molecular assembly and crystal growth via directional multiple hydrogen‐bonding motifs at the molecular termini and short C─H··· π contacts at the center. A facile solvent vapor annealing induces concurrent dewetting and microscopic 1D random crystallization, yielding a woven‐textured random features. Using convolutional neural networks, the rich variations in microcrystal domain properties and stochastic encoding of 1D crystal orientations generate artificial coloration, achieving an encoding capacity reaching (6.5 × 10⁴) (2752 × 2208) . The results demonstrate an effective strategy for achieving ultrahigh encoding capacities in a thin film composed of a single‐material. This approach enables low‐cost, solution‐processed fabrication for mass production and broad adoption, while opening new opportunities to explore molecular ‐PUFs through structural design and engineering noncovalent interactions.
Journals
2025 EN
Maity Sukanya · Ibrahim Mohamed · Badr Hussein
+6 more
Abstract Nanostructured titania, TiO 2 , holds significant importance in various scientific fields and technologies for their distinctive properties and multipurpose characteristics. In this article, the facile, economical, and scalable synthesis of 1D lepidocrocite, 1DL, titania nanostructures derived from a water‐soluble Ti precursor, titanium oxysulfate (with oxidation of Ti +4 ) at temperature <100 °C under atmospheric pressure is discussed. Titanium oxysulfate with tetramethyl ammonium hydroxide, TMAH, is simply reacted to yield individual lepidocrocite titania‐based chain‐forming nanofilaments, NFs, 6 × 6 Å 2 in minimal cross‐section and aspect ratios of ≈20 1DLs. If only ethanol is used for washing, the 1DL self‐assemble into ≈10 µm, porous mesostructured particles, PMPs. If water is used, quasi‐2D sheets form instead. Characterization of the resulting powders showed them to be quite similar to those derived from TiB 2 , and other water‐insoluble Ti precursors. The 1DL bandgap energies are ≈4 eV, due to quantum confinement. They adsorbed rhodamine 6G. The latter also sensitized the 1DLs and allowed for dye degradation using only visible light. Used as electrodes in supercapacitors, the 1DLs can be cycled over 1.6 V and result in high power densities (300 W kg −1 ). Stronger birefringence started to appear in samples with concentrations >15 gL −1 indicating the formation of a liquid crystal phase. This new synthesis protocol enables the cheaper scalable production of 1DLs with significant implications across various fields.
Journals
2025 EN
Dharmalingam Swathi Tharani · Dar Mushtaq Ahmad · Gul Rukhsana
+3 more
Abstract Nano‐octahedron cobalt oxide decorated graphene nanocomposite is reported in this work for selective and simultaneous determination of dopamine (DA) and uric acid (UA). The composite is synthesized using a hydrothermal method and characterized to identify the crystal structure and its shapes. The Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) images indicate the silhouette image of the nanocube decorated over graphene oxide. The Gr‐Co₃O₄/glassy carbon electrode (GCE) is utilized for the electrochemical detection of dopamine (DA). Cyclic voltammetry (CV) studies revealed a significant breakthrough such as Gr‐Co₃O₄/GCE exhibited higher electrocatalytic activity for DA oxidation than the bare GCE. Differential pulse voltammetry (DPV) measurements demonstrated a detection limit of 0.09 µM for DA, with a linear response range from 1 to 500 µM. For uric acid (UA), the detection limit and linear range are estimated as 0.2 and 100 to 8000 µM, respectively. The sensor selectively detects DA in the presence of UA is confirmed, with a peak separation of 250 mV between DA and UA. The reliability of the sensor is validated through using human serum specimens, paving the way for exciting potential applications in biomedical research and clinical diagnostics.
Journals
2025 EN
Narh Daniel · Alabani Yushaw D. · Okrah Petrina
+6 more
Abstract The unique properties of superhydrophobic surfaces are explored for various applications. In this study, superhydrophobic nanostructured surfaces are fabricated on glass substrates using titanium dioxide (TiO 2 ), silver‐coated titanium dioxide (Ag‐TiO 2 ), and halloysite clay nanotubes (HNTs). The noble metal, silver (Ag, 0.5 wt.%) is loaded onto TiO 2 by the photodeposition method. Characterization techniques, including X‐ray diffraction, Raman, and Fourier‐transform Infrared spectroscopy, confirm the formation of the nanocomposites. The thermogravimetric analysis demonstrates thermal stability, and optical microscopy reveals an even distribution of the nanocomposite on the glass substrate. Nanocomposites of HNT‐Ag‐TiO 2 and HNT‐TiO 2 , with varying percentages of HNTs, are synthesized and spray‐coated onto a glass substrate while modified with myristic and stearic acid. A superhydrophobic contact angle of 159.35° ± 2.7° and a sliding angle of 8° is obtained for HNT‐TiO 2 ‐stearic acid with 66.67 wt.% TiO 2 . Additionally, HNT‐TiO 2 ‐stearic acid exhibits excellent chemical, mechanical, and thermal stability. The nanocomposite also displays self‐cleaning properties, effectively shedding kaolin and carbon black contaminants.
Journals
2025 EN
Ibrahim Kassa Belay · Michelutti Tommaso · Gradone Alessandro
+7 more
Abstract Water splitting is a promising and sustainable technology that can address energy and environmental challenges by producing clean H 2 without emissions of harmful pollutants. However, alkaline water oxidation is the most relevant process at the industrial level, and it faces obstacles due to unfavorable thermodynamics and high overpotential. The search for new environmentally friendly materials with high activity and low cost is a significant challenge. Herein, Mn 2 P 4 O 12 microspheres are synthesized from MnO 2 nanosheets via hydrothermal and chemical vapor deposition processes by regulating phosphorization as a new material in water‐splitting catalysis. The spherical Mn₂P₄O₁₂ microstructures act as pre‐catalysts and undergo surface reconstruction during electrochemical activation, leading to the formation of β‐MnO₂ as the true active phase. Once stabilized, they exhibit outstanding catalytic performance (250 and 510 mV at 10 and 100 mA cm −2 with Tafel slope as low as 40.80 mV dec −1 ) and stability for more than 32 h at different potentials. The in situ surface reconstruction highlighted by a multi‐technique analysis ensures the catalyst's stability and results in efficient catalytic active sites for adsorbed oxygen, which enhances overall performance. This study provides insights into cyclotetraphosphate catalysis and offers a pathway for developing efficient and cost‐effective materials for water electrolysis.
Journals
2025 EN
Wang Suhao · Wei Huan · Rillaerts Antoine
+11 more
Abstract The development of n‐type organic thermoelectric materials, especially π‐conjugated small molecules, lags far behind their p‐type counterparts, due primarily to the scarcity of efficient electron‐transporting molecules and the typically low electron affinities of n‐type conjugated molecules that leads to inefficient n‐doping. Herein, the n‐doping of two functionalized (carbonyl vs dicyanovinylene) indenofluorene‐based conjugated small molecules, 2,8‐bis(5‐(2‐octyldodecyl)thien‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐dione (TIFDKT) and 2,2′‐(2,8‐bis(3‐alkylthiophen‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐diylidene)dimalononitrile (TIFDMT) are demonstrated, with n‐type dopant N‐DMBI. While TIFDKT shows decent miscibility with N‐DMBI, it can be hardly n‐doped owing to its insufficiently low LUMO. On the other hand, TIFDMT, despite a poorer miscibility with N‐DMBI, can be efficiently n‐doped, reaching a respectable electrical conductivity of 0.16 S cm −1 . Electron paramagnetic resonance measurements confirm the efficient n‐doping of TIFDMT. Based on density functional theory (DFT) calculations, the LUMO frontier orbital energy of TIFDMT is much lower, and its wave function is more delocalized compared to TIFDKT. Additionally, the polarons are more delocalized in the n‐doped TIFDMT. Remarkably, as indicated by the grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), the molecular order for TIFDMT thin‐film is enhanced by n‐doping, leading to more favorable packing with edge‐on orientation and shorter π‐π stacking distances (from 3.61 to 3.36 Å). This induces more efficient charge transport in the doped state. Upon optimization, a decent thermoelectric power factor of 0.25 µWm −1 K −2 is achieved for n‐doped TIFDMT. This work reveals the effect of carbonyl vs dicyanovinylene on the n‐doping efficiency, microstructure evolution upon doping and thermoelectric performance, offering a stepping stone for the future design of efficient n‐type thermoelectric molecules.