Ultrasonic Exfoliation Research Articles

Impact of ultrasonic probe type, frequency, and static pressure on large-scale graphene exfoliation

The ultrasonic liquid phase exfoliation method has emerged as an essential research direction for graphene preparation due to its cost-effectiveness and ability to minimize defects. However, this method faces challenges related to processing throughput when scaled up for industrial production. In this study, industrial grade ultrasonic homogenizers with different frequencies and probe types were evaluated for the preparation of FLG. In each experiment, 1.5 kg of graphite slurry was treated using a cyclic ultrasonic system. The results demonstrated that the 25 kHz dumbbell probe produced the thinnest FLG with the lowest defect density. Moreover, applying a static pressure of 0.2 MPa in the cycle system enhanced the cavitation-induced exfoliation of graphite sheets, effectively reducing the layer count and distribution range of FLG. This method improves the conductivity while minimizing defect density.

Rapid and eco-friendly ultrasonic exfoliation of transition metal dichalcogenides supported on sonogel-nanocarbon black: A non-precious electrocatalyst for hydrogen evolution reaction

Recently, there has been growing interest in replacing expensive platinum-based catalysts with cost-effective non-precious metal alternatives for water electrolysis aimed at hydrogen production. This study introduces an innovative, green, and cost-effective strategy for the development of non-precious electrocatalysts by leveraging sodium alginate-mediated ultrasonic exfoliation to produce transition metal dichalcogenide (TMD) nanosheets. These nanosheets are supported on Sonogel-Carbon electrodes (SGC), providing a novel conductive base for HER catalysis. Using a diverse array of TMD materials, including MoS2, MoSe2, WS2, and WSe2, we assess their catalytic activity towards HER. The study demonstrates significantly enhanced HER performance through bulk modification of the electrodes with nanocarbon black (SGC-CB). This enhancement is primarily due to the synergistic effects of improved electron transfer and increased active site availability, facilitated by the unique structural properties of the exfoliated TMD nanosheets and the conductive Sonogel-Carbon substrate. Notably, the optimized MoSe2NS-SGC-CB configuration achieves an exceptional overpotential of 240 mV at a current density of 10 mA/cm2, surpassing conventional bulk catalysts and highlighting the potential of sodium alginate as a viable dispersing agent for the large-scale production of TMD nanosheets. The operational stability and cost-effectiveness of this electrocatalyst, combined with its environmental friendliness, mark a significant step forward in the pursuit of sustainable hydrogen fuel production technologies.

Polymer functionalized antimony sulfide quantum dots for broadband optical limiting.

The rapid development of zero-dimensional quantum dots-based nanotechnology has motivated the design and synthesis of novel nano-functional materials for optoelectronic and photonic devices in recent years. Antimony sulfide (Sb2S3) quantum dots (SQDs), with an average diameter of 3.22 nm, were prepared via a top-down liquid ultrasonication exfoliation technique. Highly soluble poly(N-vinylcarbazole)-covalently functionalized SQDs (SQDs-PVK) were synthesized in situ by reversible addition fragmentation chain transfer polymerization, and embedded into a non-optically active poly(methylmethacrylate) (PMMA) matrix giving the SQDs-PVK/PMMA film. The annealed SQDs-PVK/PMMA film showed exceptional nonlinear optical performance, with large nonlinear absorption coefficients of 713.71 cm GW-1 at 532 nm and 913.60 cm GW-1 at 1064 nm, and small limiting thresholds of 1.44 J cm-2 at 532 nm and 1.08 J cm-2 at 1064 nm. These advantages make SQDs-PVK one of the promising candidates for a broadband optical limiter in both the near-infrared and visible ranges.

Heterostructured g-C3N4-TiO2 nanocomposites applied to p-toluic acid degradation under solar light-induced photocatalytic process

In this work, heterostructured photocatalysts were prepared with TiO2-P25 nanocrystals dispersed on two-dimensional layers of g-C3N4. Different g-C3N4:TiO2 ratios (25 %, 50 % and 75 %) were prepared using a wet method under ultrasonic exfoliation and thermal treatment under an oxidizing atmosphere. The heterojunctions were confirmed by X-ray diffraction, and electron microscopy, showing TiO2 nanocrystals anchored onto the surface of the g-C3N4 structure. The obtained heterojunctions increased light absorption from the ultraviolet to the visible spectrum and reduced the recombination of photoinduced charge carriers confirmed by photoluminescence and band gap energy (Eg) measurements. The photocatalytic performance was evaluated in the degradation of p-toluic acid (p-TA) (20 mg L–1) under UVA LED at 365 nm, a polychromatic lamp (UVA-UVB-visible) and solar radiation. The g-C3N4:TiO2 ratio of 25 % showed the best performance, reaching 95 % degradation after 180 min under solar radiation. The reuse tests showed that the mineralization capacity determined by total organic carbon (TOC) remained stable for 6 cycles, achieving 80.8 % TOC degradation. The heterojunction induced a significant alteration in the rheological behavior of the suspension, which made the g-C3N4-TiO2 easily recoverable, unlike the pure TiO2. The radical scavengers study indicated that the superoxide anion radical (O2•–) is the main oxidative species in p-TA photodegradation on g-C3N4-TiO2 photocatalyst. The greatest advantage of the g-C3N4 in the composite was the absorption of light in the visible range and facile catalyst recovery for reuse while presenting photocatalytic activity similar to TiO2.

Fluorinated boron nitride nanosheets for high thermal conductivity and low dielectric constant silicone rubber composites

AbstractIncreasing miniaturization and integration of microelectronic devices have led to an unprecedented attention on heat dissipation and signal transmission of electronic equipment. However, the mostly used method to enhance the thermal conductivity of polymers by adding thermally conductive fillers usually results in the increase of dielectric constant (Dk). It was still challenging to synergistically achieve low Dk and high thermal conductivity of polymer‐matrix composites. Herein, hydroxylated boron nitride nanosheet (BNNS‐OH) with a high yield of 35.67% was prepared by the liquid ultrasonic exfoliation under the assistance of sodium cholate (SC), and grafted with (1H,1H,2H,2H‐perfluorodecyl) trimethoxy silane to prepare fluorinated boron nitride nanosheets (F‐BNNS), which can uniformly disperse in liquid silicone rubber (LSR) and reduce the Dk of LSR composites. The thermal conductivity of LSR composites with 20 wt% F‐BNNS reached 0.489 W·m−1·K−1, showing an increase of 307.35% in comparison with pure LSR (0.12 W·m−1·K−1). Meantime, the Dk of as‐obtained LSR/F‐BNNS (20 wt%) composites is reduced from 3.4 to 2.6, and the dielectric loss (Df) is less than 0.012. The facile and rational design of fluorinated BNNS offers a new insight for the high‐end electronic packaging materials.Highlights A new method of exfoliation and fluorinated treatment of h‐BN was proposed. The LSR composites achieved an ultralow Dk of 2.63 via fluorinated BNNS. Thermal conductivity of LSR composites increased by 307.35% than pure LSR.

Microwave absorption parameters over 2–18 GHz frequency range for the MXene composite – Ti3C2Tx @MnCo2O4

The great potential for electromagnetic wave (EMW) absorption is revealed in two-dimensional (2D) Ti3C2Tx (MXene) thin sheets that have numerous surface flaws and an extensive spectrum of functional groups. In this study, Ti3AlC2 (MAX Phase) is etched, and then ultrasonic exfoliation is used to create 2D ultrathin Ti3C2Tx nanosheets; a type of MXene. The MnCo2O4 spherical particles were grown on the layered structure of Ti3C2Tx via a one-pot hydrothermal process. The synthesized Ti3C2Tx/MnCo2O4 composite provides superior bulk-to-surface and interfacial charge transfer capabilities due to their short charge transfer distance and extensive interface contact area to the EMW. This article thoroughly evaluates the loss impact in Ti3C2Tx/MnCo2O4 absorbers as -44.4dB of reflection loss at 16.04GHz with a thickness of 5.114mm for the first time, which is essential for fabricating an effective microwave absorber.

In Situ PL Probes the Effect of 2D SnSe Nanosheets on the Crystallization Process of CsPbI2Br Perovskite Solar Cells.

Reducing defects in the active layer is important for improving the crystalline quality of all-inorganic perovskite solar cells (PSCs). Exploring novel additives is one of the most promising approaches to minimize active layer defects. In this work, two-dimensional (2D) SnSe nanosheets with excellent optoelectronic properties are prepared using an ultrasonic exfoliation method. The prepared 2D SnSe nanosheets are introduced into a CsPbI2Br precursor, which reduces the defect formation at grain boundaries and enhances the crystallinity of CsPbI2Br perovskites. We use the in situ photoluminescence (PL) technique to investigate the role of 2D materials in the crystallization process. The results show that SnSe nanosheets primarily shorten the grain boundary merging time and reduce the defect generation during the grain boundary merging stage, thereby regulating the crystallization of perovskite. In addition, SnSe nanosheets passivate uncoordinated Pb atoms at grain boundaries by Se atoms, further reducing the defect density in perovskite. As a result, PSCs exhibit a higher power conversion efficiency (PCE) of 14.24% and a Voc of 1.22 V. This study highlights the role of 2D materials in enhancing the crystalline quality and PCE of PSCs.

Optical and Electrical Properties of Spin Coated Bilayer Graphene

Graphene is a 2D material with high transparency, high carrier mobility, and high electrical conductivity [1-4]. In this work, a thin graphene layer was coated on Si through spin coating, and dip coating technique.Graphene ink was prepared by expanding the graphite flakes through microwave irradiation followed by ultrasonic liquid phase exfoliation. 5 mg of the resulting graphene was dispersed in 1 ml of IPA through a probe sonication technique to obtain the graphene suspension/ink. To form the graphene/Si junction, pieces of 3 x 3 cm2 of n-type Si were used. In addition, same size of fused silica were used to measure the reflectance of deposited graphene. The graphene layer in the first sample was formed by spin coating 40 µl of graphene ink on the Si and the fused silica at a speed of 200 rpm for 40 s. The second sample was prepared by dip coating technique, where 13 ml of the graphene ink was added to 47 ml of IPA, followed by dipping Si and the fused silica pieces with a speed of 20 mm/min till they immersed completely and were kept for 1 min and were moved up at the same speed and dried at room temperature. This dip-coating process was repeated 10 times for each sample.The morphology of graphene-coated area was analyzed using the SEM technique. The SEM images of the spin-coated shows that the surface is fully covered with graphene flakes of different sizes stacked on each other with varied orientations, this shows the ability to obtain a continuous coating of graphene by spin coating. Also, Hall effect measurements were performed, and it showed that the conductivity of the Si substrate was 1.95x10-2 ohm-1cm-1, and it increased to 2.74 ohm-1cm-1 after adding the graphene. Finally, the reflectance of the graphene on fused silica was measured using a UV-VIS spectrophotometer, and it showed that the reflectance decreased from 8% to 4% in the range from 360 to 860 nm after adding the graphene.For dip-coated sample, the SEM image shows some voids, and empty areas linked with by graphene structure with a width of few microns, this shows that the dip-coating process needs to be optimized to get a full coverage of the surface. The electrical measurement of this sample showed that the conductivity increased to 2.66 ohm-1cm-1 after the dip coating of graphene. For the reflectance measurements, it was observed that the graphene has decreased the reflectance to 6-7% in the range from 360 to 860 nm.Finally, spin coating at higher speed, and less amount of graphene can be tested, to obtain a thinner graphene layer. For the dip coating process, higher graphene concentration in IPA, and longer immersion time will be investigated to get a better coverage.

Mechanical Robust and Conductive Polyurea Nanocomposites Using Graphene Platelets

Graphene, renowned for its exceptional surface area, electrical and thermal conductivity, and gas permeation resistance, serves as an excellent filler for enhancing the properties of polyurea (PUA). In this study, graphene platelets (GNPs) were mass-produced via thermal expansion of graphite intercalation compound followed by ultrasonic exfoliation. These GNPs were then incorporated into PUA using a straightforward mixing method to create PUA/GNPs composites. Characterization using SEM and a high resistivity meter revealed strong interfacial bonding between GNPs and the PUA matrix, facilitated by isophorone diisocyanate (IPDI) and Jeffamine D2000 (D2000). This robust interaction significantly improved the composites' performance. Notable enhancements in mechanical properties were observed: tensile strength increased by approximately 79% at 0.5 vol%, impact strength by 15.7% at 0.2 vol%, and tear strength by 30.6% at 0.5 vol%,. These improvements underscore the effectiveness of GNPs as reinforcing fillers, significantly boosting the durability and robustness of the PUA composites. Additionally, the study examined the effect of varying graphene content on the electrical properties of the composites, revealing substantial improvements in electrical conductivity. This research presents a practical strategy for developing high-performance PUA/GNPs composites, leveraging GNP's unique properties to enhance both mechanical and electrical characteristics. The study contributes valuable insights into the synthesis and property enhancement of GNPs nanocomposites, paving the way for further advancements in the field of multifunctional materials.

Ultrasound‐assisted liquid phase exfoliation of boron nitride nanosheets as fillers for polyacrylate pressure‐sensitive adhesives with enhanced thermal conductivity

AbstractHexagonal boron nitride (h‐BN) is widely used as a filler to improve the thermal conductivity of polymers due to the high thermal conductivity, electrical insulation, and chemical stability. However, the small lateral‐size and poor compatibility limit h‐BN's performances and applications in thermal management. Here, boron nitride nanosheets (BNNSs) were prepared by liquid‐phase ultrasonic exfoliation using isopropanol (IPA) as solvent. Specifically, the BNNSs obtained by ultrasonication for 8 h with an initial concentration of h‐BN of 8 mg/mL have the best exfoliation effect and a high yield of 19.8%, showing a large lateral‐size of 1–2 μm and an ultra‐thin thickness. Then, the resulting BNNSs can be modified by grafting silane coupling agent of KH560 (m‐BNNSs), their micromorphology and chemical composition are characterized by various microscopies and spectrometers. Subsequently, polyacrylate pressure‐sensitive adhesives (PSAs) composites are prepared using m‐BNNSs as a thermally conductive filler by UV bulk polymerization, their thermal conductivity can be greatly improved by 250% compared with that of pure PSAs. For comparison, the thermal conductivity of m‐BNNSs/PSAs composites with filler content of 25 wt% is as high as 0.4382 W/(m K), which is 1.6 times higher than that of h‐BN/PSAs composites. In addition, the incorporation of BNNSs will improve the thermal stability, hardness, and 180° peeling force of the PSAs composites, which will stimulate the practical application of PSAs materials.

X-ray peak broadening analysis of Bougainvillea glabra assisted ultrasonic exfoliation of h-BN sheets

In this study, h-Boron Nitride (h-BN) nanosheets have been successfully exfoliated using Bougainvillea flower extract and ultrasonication process. The microstructural parameters such as microstrain, stress, and energy density were calculated using Williamson–Hall analysis. The time of ultrasonication and post-annealing temperature significantly alter the microstructure parameters such as crystal size, microstrain, stress, and energy density upon sonication. The lattice constants such as a-axis and c-axis, cell volume, and bond length did not alter significantly which confirms that there is no crystal structure deformation upon sonication and annealing processes. FESEM result revealed that exfoliation of h-BN and ultrasonication duration greatly influenced the exfoliation. Raman and FTIR studies confirm the pure phase of h-BN without secondary impurities. A simple ultrasonication process would effectively exfoliate h-BN layers and this could be used for tribological applications to reduce the friction between rubbing surfaces.

Dual frequency ultrasonic liquid phase exfoliation method for the production of few layer graphene in green solvents

In this work, we implement a dual frequency (24 kHz and 1174 kHz) ultrasonic assisted liquid phase exfoliation (ULPE) technique in deionized water (DIW) and other eco-friendly solvents, to produce a variety of high-quality few-layer graphene (FLG) solutions under controlled ultrasonication conditions. The resulting FLG dispersions of variable sizes (∼0.2–1.5 μm2) confirmed by characterisation techniques comprising UV–Vis spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy (HR-TEM). For the first time we demonstrate that high yield of FLG flakes with minimal defects, stable for 6 + months in a solution (stability ∼ 70 %), can be obtained in less than 1-hour of treatment in either water/ethanol (DIW:EtOH) or water/isopropyl alcohol (DIW:IPA) eco-friendly mixtures.We also scrutinized the underlying mechanisms of cavitation using high-speed imaging synchronized with acoustic pressure measurements. The addition of ethanol or IPA to deionized water is proposed to play a central role in exfoliation as it regulates the extend of the cavitation zone, the intensity of the ultrasonic field and, thus, the cavitation effectiveness. Our study revealed that lateral sizes of the obtained FLG depend on the choice of exfoliating media and the diameter of a sonotrode used. This variability offers flexibility in producing FLG of different sizes, applicable in a wide spectrum of size-specific applications.

Advances In Borophene: Synthesis, Tunable Properties, and Energy Storage Applications.

Monolayer boron nanosheet, commonly known as borophene, has garnered significant attention in recent years due to its unique structural, electronic, mechanical, and thermal properties. This review paper provides a comprehensive overview of the advancements in the synthetic strategies, tunable properties, and prospective applications of borophene, specifically focusing on its potential in energy storage devices. The review begins by discussing the various synthesis techniques for borophene, including molecular beam epitaxy (MBE), chemical vapor deposition (CVD), and chemical methods, such as ultrasonic exfoliation and thermal decomposition of boron-containing precursors. The tunable properties of borophene, including its electronic, mechanical, and thermal characteristics, are extensively reviewed, with discussions on its bandgap engineering, plasmonic behavior, and thermal conductivity. Moreover, the potential applications of borophene in energy storage devices, particularly as anode materials in metal-ion batteries and supercapacitors, along with its prospects in other energy storage systems, such as sodium-oxygen batteries, are succinctly, discussed. Hence, this review provides valuable insights into the synthesis, properties, and applications of borophene, offering much-desired guidance for further research and development in this promising area of nanomaterials science.

Green production of functionalized few-layer borophene decorated with cerium-doped iron oxide nanoparticles for repeatable hydrogen peroxide detection

Functionalized few-layer borophene (FFB) was prepared using gallnut extract and coffee waste extract as natural exfoliating and stabilizing agents in an environmentally friendly ultrasonic and high shear exfoliation. Here, a facile precipitation method was employed to grow iron oxide nanoparticles doped with cerium (Ce-FeONPs) onto the surface of FFB. This intriguing combination of materials yielded Ce-FeONPs nanoparticles that exhibited exceptional peroxidase-like activity, efficiently catalyzing the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue oxidized TMB (oxTMB) in the presence of hydrogen peroxide (H2O2). Additionally, the introduction of FFB contributes a reducibility effect to the catalytic oxidation of TMB, facilitating the restoration of the oxTMB to TMB. Thus, FFB-Ce-FeONPs showcase intriguing properties encompassing both oxidative and reductive characteristics, suggesting their potential as a reagent for repeated detection of H2O2. Moreover, a colorimetric sensing system enabled the liner detection of H2O2 spanning a concentration range from 0.08 to 1 mM, with a detection limit of 0.03 mM. Noteworthily, FFB-Ce-FeONPs demonstrated sustained efficacy over ten successive recycling cycles, as indicated by consistent slopes and observable color changes. In summary, this work reports the first application of nanoenzymes in repetitive H2O2 detection. Even after ten multiple cycles, the detection limit remains virtually unaltered, underscoring the robustness and enduring effectiveness of the engineered nanomaterial. The proposed simultaneous oxidation and reduction strategies for detecting H2O2 showed a commendable capability in ten cycles of H2O2 detection, thus providing a promising approach in the field of H2O2 detection.

Preparation of a Nanosheeted Uranyl-Organic Framework for Enhanced Photocatalytic Oxidation of Toluene.

Preparation of ultrathin metal-organic framework (MOF) nanosheets is an effective way to improve the catalytic efficiency of MOF photocatalysts owing to their superiority in reducing the recombination rate of photogenerated electrons and holes and enhancing charge transfer. Herein, a light-sensitive two-dimensional uranyl-organic framework named HNU-68 was synthesized. Due to its interlayer stacking structure, the corresponding ultrathin nanosheets with a thickness of 4.4 nm (HNU-68-N) can be obtained through ultrasonic exfoliation. HNU-68-N exhibited an enhanced ability to selectively oxidize toluene to benzaldehyde, with the value of turnover frequency being approximately three times higher than that of the bulk HNU-68. This enhancement is attributed to the smaller size and interface resistance of the layered HNU-68-N nanosheets, which facilitate more thorough substrate contact and faster charge transfer, leading to an improvement in the photocatalytic efficiency. This work provides a potential candidate for the application of ultrathin uranyl-based nanosheets.

A key parametric study of ultrasonic exfoliation of 2D TiB2 using DI water as a unique medium

Liquid Phase Exfoliation (LPE) is a very effective technique for the synthesis of few layered two dimensional (2D) nanosheets. There is a surge to find environment friendly solvents for efficient exfoliation of layered materials to produce 2D nanosheets. TiB2 is an important layered material with very little reported work on its 2D nanosheets. The present work is about successful LPE of TiB2 using deionized (DI) water as a clean, green and low cost dispersion medium to make TiB2 nanosheets. The impact of ultrasonication conditions i.e. input power and treatment duration for efficient synthesis of few layered 2D nanosheets in DI water is studied by Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). It is found that by increasing input power, the layer thickness is reduced from bulk to 34 nm with lateral dimensions as huge as up to 5 μm. The increased treatment duration has further reduced the layer thickness to 21 nm associated with a decrease in lateral dimensions to about 1 μm. The mechanism of variation in the aspect ratio of the 2D nanosheets with ultrasonication power and treatment duration is explained. The optimum conditions for the fabrication of high aspect ratio 2D nanosheets of TiB2 owe to a greater acoustic cavitation intensity, an optimum treatment duration and a homogenous distribution of the cavitation events while using an appropriate size of the sonotrode in the sonicated volume during ultrasonication.

Synthesis, Characterization, and Photocatalytic Performance of ZnFe2O4-g-C3N4 Composites for Tetracycline Removal from Contaminated Water

The presence of emerging contaminants in wastewater like tetracycline poses a significant challenge in water reuse worldwide. The implementation of a p-n heterojunction and dye-sensitized techniques in the enhancement of graphite carbon nitride provides a promising alternative for visible light-driven degradation of emerging contaminants present in wastewater. The present study investigated dye-sensitized and plain composites in degrading tetracycline using natural sunlight in a parabolic trough reactor. The study synthesized four composites of ZnFe2O4-g-C3N4 at 5, 15, and 25 wt% loading of the ferrite by direct annealing of melamine, followed by thermal and ultrasonic exfoliation of bulk graphite carbon nitride and in situ precipitation with zinc ferrites to yield a composite photocatalyst. The photocatalysts were characterized using X-ray diffraction (XRD) analyses which confirmed that all the spinel ferrite phases of ZnFe2O4 were well bonded with g-C3N4 nanosheets to form a composite. The crystallite sizes were calculated by the Debye–Scherrer equation indicating crystal sizes of between 4.63 and 8.61 nm confirming the nanostructures. The scanning electron microscope-energy dispersive spectroscopy (SEM-EDX) tests verified that the spherical globules of ZnFe2O4 were well attached to the mesoporous layers of g-C3N4 and absence of contaminant phases. The UV-Vis analysis for 25% ZF-GCN revealed a band gap reduction from 2.67 eV to 2.03 eV. The PL intensity for all the composites decreased at excitation of 266 nm and 550 nm which was evidence for suppressed charge recombination. A 25% ferrite loading resulted in the best photocatalytic performance with tetracycline degradation of 93.64% and total organic carbon (TOC) removal of 51.89%. The sensitization of the 25% ZF-GCN composite with Eosin Y further improved its performance for degradation of tetracycline to 94.62% and TOC removal to 68.29%. Therefore, dye sensitization is an efficient way of improving the photocatalytic activity of a multicomponent photocatalyst for the removal of emerging pollutants.

Utilizing ultrasonic liquid exfoliation for producing graphene from rice stem: Exploring cellular components and functionalities

This study investigates a prospective and straightforward method for producing graphene material derived from biomass, examining the influence of plant cell composition and functions. The experimental outcomes highlight ultrasound's crucial role in synthesizing graphene material sourced from biomass. Ultrasound, a pivotal element in the experiment, significantly affects graphene production from biomass by working synergistically with the liquid components in the solvent system. Notably, the ethanol content reduces the solution’s surface tension, facilitating the effective dispersion of biochar and graphene oxide sheets throughout the process. Simultaneously, the water content maintains the solution’s polarity, enhancing the cavitation effect induced by ultrasound. Biomass-derived graphene is exfoliated utilizing an ultrasonic bath system (134.4 W, 40 kHz, 0.5 W/cm2) from biochar. The as-synthesized graphene oxide exhibits a structure comprising a few layers while remaining intact, featuring abundant functional groups. Interestingly, the resulting product displays nanopores with an approximate diameter of 100 nm. These nanopores are attributed to preserving specific cell structures, particularly those with specialized cell wall structures or secondary metabolite deposits from biomass resources. The study's findings shed light on the impact of cellular structure on synthesizing graphene material sourced from biomass, emphasizing the potential application of ultrasound as a promising approach in graphene production.

Efficient light-emitting diodes from emitters of TaSe2 quantum dots and pure carbon dots and carrier injection tailoring of TaSe2

Solution-processed symbiotic TaSe2 quantum dots and carbon dots (TaSe2-QDs/CDs) and pure CDs have been facilely synthesized via liquid-phase ultrasonic exfoliation and hydrothermal reaction. Symbiotic TaSe2-QDs/CDs and CDs show good film morphology and excitation wavelength-dependent photoluminescence. With CDs (TaSe2-QDs/CDs) as emitter, efficient light-emitting diodes (LEDs) are assembled, showing maximum luminance of 217 (640) cd/m2, external quantum efficiency (EQE) of 0.11 % (0.21 %), luminous efficiency of 0.135 (0.262) cd/A, and power efficiency of 0.045 (0.095) lm/W. Resonance energy transfer from CDs to TaSe2-QDs contributes to the enhanced performance in TaSe2-QDs/CDs based LED. With 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as emitters, normal and inverted UV organic LEDs (OLEDs) are realized using TaSe2-QDs/CDs tailoring hole and electron injection, respectively. The normal (inverted) UV OLEDs show maximum radiance of 1.14 (1.3) mW/cm2, EQE of 0.89 % (0.37 %), and electroluminescence peak of 397 (395) nm. Impedance spectroscopy and current versus voltage characteristics are performed to clarify some mechanisms.

Transition Metal Oxide-Decorated MXenes as Drugless Nanoarchitectonics for Enriched Nanocatalytic Chemodynamic Treatment.

Despite their unique characteristics, 2D MXenes with sole photothermal conversion ability are required to explore their superfluous abilities in biomedicine. The small-molecule-based chemotherapeutics suffer from various shortcomings of time-consuming and expensiveness concerning theoretical and performance (preclinical/clinical) checks. This study demonstrates the fabrication of Ti3C2 MXene nanosheets (TC-MX NSs) and subsequent decoration with transition metal oxides, that is, copper oxide (Cu2O/MX, CO-MX NCs) as drugless nanoarchitectonics for synergistic photothermal (PTT)-chemodynamic therapeutic (CDT) efficacies. Initially, the monolayer/few-layered TC-MX NSs are prepared using the chemical etching-assisted ultrasonic exfoliation method and then deposited with Cu2O nanoconstructs using the in situ reduction method. Further, the photothermal ablation under near-infrared (NIR)-II laser irradiation shows PTT effects of CO-MX NCs. The deposited Cu2O on TC-MX NSs facilitates the release of copper (Cu+) ions in the acidic microenvironment intracellularly for Fenton-like reaction-assisted CDT effects and enriched PTT effects synergistically. Mechanistically, these deadly free radicals intracellularly imbalance the glutathione (GSH) levels and result in mitochondrial dysfunction, inducing apoptosis of 4T1 cells. Finally, the in vivo investigations in BALB/c mice confirm the substantial ablation of breast carcinoma. Together, these findings demonstrate the potential synergistic PTT-CDT effects of the designed CO-MX NCs as drugless nanoarchitectonics against breast carcinoma.