Dual Graphene Research Articles

Design of encoded graphene-gold metasurface-based circular ring and square sensors for brain tumor detection and optimization using XGBoost algorithm

This study introduces a circular ring and square metasurfaces-based sensor employing graphene and gold layers for enhanced brain tumor detection. The sensor architecture includes dual graphene circular metasurfaces and a gold square resonator layer on a silicon dioxide substrate. A comprehensive parametric investigation explores the influence of geometric parameters and graphene chemical potential on sensor performance. The sensor achieves a remarkable sensitivity of 769 GHzRIU−1, a high-quality factor of 6.514, a low detection limit of 0.182 RIU, and an FOM of 1.148RIU−1. Electric field intensity analysis identifies optimal transmission frequencies. By employing the XGBoost regressor, the analysis significantly reduces simulation time and resource consumption by at least 80 %. Simulation validation confirms that despite 80 % reduction in simulation time, high prediction accuracy remains achievable, with an impressive R2 score ranging from 0.9 to 1. The proposed sensor presents a promising non-invasive approach for early brain tumor diagnosis, with potential applications in biomedical imaging and other related fields.

Graphene-based synthetic peptide electrochemical sensor for colorectal cancer diagnosis

This work reports the development of an electrochemical sensor using graphene-peptide conjugates for detecting colorectal cancer (CRC) biomarker leucine-rich alpha-2 glycoprotein-1 (LRG1). To enable LRG1 quantification, we rationally designed peptides with dual graphene anchoring motifs for optimal orientation and binding activity when immobilized on a reduced graphene oxide (rGO) electrochemical transducer surface. The graphene nanomaterial provides several advantages such as high conductivity, large surface area, and excellent stability that can enhance the sensor's analytical performance metrics. Furthermore, the synthetic peptides offer benefits like smaller size, specificity, ease of modification and cost-effective production compared to traditional antibody receptors. Under optimized conditions, the peptide sensor exhibited high sensitivity of 22.3 μA/(ng/mL.cm2), low limit of detection (75 pg/mL LRG1 in serum), accuracy of 101.1 % spiked recovery, and precision within 6 % RSD. Testing with colonoscopy-classified patient serum specimens discriminated normal, precancerous adenomatous polyps and malignant carcinoma stages based on LRG1 overexpression. A 24 % elevation for adenomas and 103 % higher levels in CRC were observed. Validation with spiked plasma samples indicated 97–104 % recovery and <7 % RSD, proving accurate detection capability. Comparison to antibody-based sensors showed superior linear range, sensitivity, reproducibility, and faster assay time. This demonstrates the promise of computational peptide designing combined with advanced nanomaterials for electrochemical detection of CRC progression through serum protein biomarkers.

Plasmon logic gates and dual-narrowband absorption switching effect in hybrid structure composed of silver and spaced dual graphene monolayers

We propose a hybrid structure composed of a silver mirror and two spaced graphene monolayers to enhance light absorption. A broad plasmon-induced reflection (PIR) window can be generated because of the destructive interference between the bright and dark modes, resulting in a dual-narrowband absorption switching effect. The dual-narrowband absorption switch is strongly dependent on the geometric structure parameters and dynamic tuning parameter of the hybrid structure, and each parameter has a wide tuning range for absorption state ‘on/on’. Especially, compared with the hybrid structure composed of a graphene monolayer and one-dimensional photonic crystal (1D PC), the proposed structure is simpler and easier to fabricate, and the dynamic tuning width of Fermi energy of graphene for light absorption state ‘on/on’ is significantly broadened (∼3 times). Compared with plasmon-induced transparency (PIT) systems, the absorption performance of graphene is greatly enhanced, and the absorption is increased from about 50% to higher than 97%. Moreover, by adjusting the widths of the graphene monolayers, NAND and NOR logic gates are realized, and the output contrast between logic states ‘1’ and ‘0’ is high up to 18.6 dB. This study may provide an approach to construct dual-narrowband absorption switches, perfect absorbers, and plasmon logic gates.

All-Optical Tunable Fiber Filter With Dual Graphene Films Enabled by a Fiber Open Microcavity

All-Optical Tunable Fiber Filter With Dual Graphene Films Enabled by a Fiber Open Microcavity

Bacterial community structure and gene function prediction in response to long-term running of dual graphene modified bioelectrode bioelectrochemical systems

This work studied bacterial community structure and gene function prediction in long-term running of dual graphene modified bioelectrode bioelectrochemical systems (LT D-GM-BE BES, 2 year). The maximum power density of LT D-GM-BE BES was 99.03 ± 3.64 mW/m2, which was 3.66 times of dual control BES (D-C-BE BES), and the transfer resistance of LT GM-BE was just approximately 1/4 of control bioelectrode (C-BE). Proteobacteria and Firmicutes were dominant bacteria in long-term modified bioanode (LT GM-BA, 30.03% and 45.64%), and in long-term modified biocathode (LT GM-BC) was Armatimonadetes (47.14%) in phylum level. The dominant bacteria in LT GM-BA was Clostridium (30.56%), in GM-BC was Chthonomonas (47.14%) in genus level. Gene function related with substrate, energy metabolism and environmental adaptation were enriched. LT GM-BE was tended to enrich dominant bacteria and enrich gene to adapt to micro-environmental changes. This study would provide metagenomics information for long-term running of BES in future.

Tunable slow light effect based on dual plasmon induced transparency in terahertz planar patterned graphene structure

We have studied a simple novel graphene ribbon structure. A very excellent and prominent dual graphene plasmon induced transparency phenomenon could be achieved by the destructive interference resulted from the excited plasmonic modes in terahertz band. Using the simple relationship between graphene and applied voltage, a good tunable effect of this structure can be achieved. The transmission of this proposed structure is theoretically investigated by using the equivalent resonator coupled mode method. The theoretical data from our proposed method are in good agreement with the numerical simulation results. Moreover, utilizing the high dispersion property, we have also researched the slow light effect for this proposed system. The results of theoretical research have indicated that the group refractive index of our proposed structure can maintain an excellent numerical value. This investigation can play a significant role in the tunable graphene-based slow light devices.

Inkjet-printed CMOS-integrated graphene\u2013metal oxide sensors for breath analysis

Early diagnosis in exhaled breath is a key technology for next-generation personal healthcare monitoring. Current chemiresistive sensors, primarily based on metal oxide (MOx) thin films, have limited applicability in such portable systems due to their high power consumption, long recovery time, poor device-to-device consistency, and baseline drifts. To address these challenges for ammonia ({{rm{NH}}}_{3}) detection in exhaled breath, a critical biomarker for a variety of kidney and liver problems, we present a formulation of a graphene–MOx functional ink-based sensing platform. We integrate our sensing layer directly onto miniaturized CMOS microhotplates (μHP) via inkjet printing, potentially enabling scalability and device-to-device performance repeatability. Using stage-by-stage temporal analysis, and a temperature-pulsed modulation (TM) strategy, we achieve ultrahigh responsivity (1500% at 10 ppm pure {{rm{NH}}}_{3}), fast response and recovery time (28 and 43 s), ultralow power consumption (~6 mW), negligible baseline drift (<0.67%), excellent cross-device and cross-cycle consistency (<0.5% and <0.41% variation in responsivity) and long-term stability (<1% variation) in our graphene–zinc oxide (ZnO) formulation, outperforming conventional MOx chemiresistive sensors. We further mitigate the effect of humidity through our measurement protocols, while interference from acetone is compensated through the parallel deployment of an additional inkjet printed graphene–tungsten oxide ({{rm{WO}}}_{3}) device as part of the sensor array. Our dual graphene–MOx formulations and their integration with ultralow power CMOS through inkjet printing represent a significant step towards reliable and portable multi-analyte breath diagnostics.

Excitation and tuning of a dual graphene plasmonic wave based on a trapezoidal grating structure

The independent excitation and tuning of a dual-band graphene plasmonic wave are realized in a hybrid structure that consists of two graphene monolayers placed above and below the trapezoidal grating. Because of the transparency of graphene in the mid-infrared range, the incident light can travel through the first graphene layer to be diffracted by the grating structure and couple its energy to both graphene layers. Numerical simulations are performed using the finite difference time domain method. Results show that the plasmon resonances corresponding to the two graphene monolayers are excited at 9.8 and 10.9μm, which agrees well with the theoretical analysis. Because of the fast and efficient electrical tunability of graphene, the resonance wavelengths can be tuned individually by changing the chemical potential of the corresponding graphene. Furthermore, the effects of geometric parameters and the refractive index of the surrounding media are studied. The results show that the structure can achieve an optimal sensing coefficient at 0.4 and 0.5eV for the top and bottom graphene plasmon resonances, respectively. The proposed structure provides an alternative option to engineer the proposed structure for sensing with high detection accuracy at mid-infrared wavelengths.

Bacterial community shift and antibiotics resistant genes analysis in response to biodegradation of oxytetracycline in dual graphene modified bioelectrode microbial fuel cell

This study explored the biodegradation mechanisms of oxytetracycline (OTC/O) and electrochemical characteristics from the perspective of bacterial community shift and OTC resistance genes in dual graphene modified bioelectrode microbial fuel cell (O-D-GM-BE MFC). In phylum level, Proteobacteria was accounted to 95.04% in O-GM-BA, Proteobacteria and Bacteroidetes were accounted to 59.13% and 20.52% in O-GM-BC, which were beneficial for extracellular electron transport (EET) process and OTC biodegradation. In genus level, the most dominant bacteria in O-GM-BA were Salmonella and Trabulsiella, accounting up to 83.04%, moreover, representative exoelectrogens (Geobacter) were enriched, which contributed to OTC biodegradation and electrochemical performances; abundant degrading bacteria (Moheibacter, Comamonas, Pseudomonas, Dechloromonas, Nitrospira, Methylomicrobium, Pseudorhodoferax, Thiobacillus, Mycobacterium) were enriched in O-GM-BC, which contributed to the maximum removal efficiency of OTC; coding resistance genes of efflux pump, ribosome protective protein and modifying or passivating were all found in O-GM-BE, and this explained the OTC removal mechanisms from gene level.

Dual Graphene Patch Antenna For Ka Band Satellite Applications

Dual Graphene Patch Antenna For Ka Band Satellite Applications

Ultrafast charge transfer in dual graphene-WS2 van der Waals quadrilayer heterostructures☆☆Supported by the National Key Research and Development Program under Grant No 2016YFA0401100, the National Natural Science Foundation of China under Grant No 61575129, the National High Technology Research and Development Program of China under Grant No 2015AA021102, and the Major Science and Technology Project of Guangdong Province under Grant

Using dual graphene–WS2 quadrilayer heterostructures as an example, we find that the ultrafast transfer of electrons from WS2 to graphene takes place within 114 fs, and the Coulomb field of the charge can effectively affect the interlayer electron transfer. This effect illustrates that the charge transfer in such van der Waals heterostructures may be controlled by an externally applied electric field for promising applications in photoelectric devices.

Biodegradation of oxytetracycline and electricity generation in microbial fuel cell with in situ dual graphene modified bioelectrode

A three-step method to prepare dual graphene modified bioelectrode (D-GM-BE) in microbial fuel cell (MFC) in previous studies. This study explored the biodegradation of oxytetracycline (OTC) and electricity generation in O-D-GM-BE MFC. The OTC removal efficiency of graphene modified biocathode and bioanode (O-GM-BC, O-GM-BA) was 95.0% and 91.8% in eight days. The maximum power density generated by O-D-GM-BE MFC was 86.6 ± 5.1 mW m−2, which was 2.1 times of that in OTC control bioelectrode (O-C-BE) MFC. The Rct of O-GM-BA and O-GM-BC were decreased significantly by 78.3% and 76.3%. OTC was biodegraded to monocyclic benzene compounds by bacteria. O-GM-BA was affected strongly by OTC, and Salmonella and Trabulsiella were accounted for 83.0%, while typical exoelectrogens (Geobacter) were still enriched after the maturity of biofilm. In O-GM-BC, bacteria related with OTC biodegradation (Comamonas, Ensifer, Sphingopyxis, Pseudomonas, Dechloromonas, etc.) were enriched, which contributed to the high removal efficiency of OTC.

Waveguide Engineering of Graphene Optoelectronics—Modulators and Polarizers

The concept of incorporating graphene into nanophotonic waveguides has pullulated into massive broadband optoelectronic applications with compact footprint. We theoretically demonstrate that by solely altering the dimension design of graphene-laminated silicon waveguides, the phase, amplitude, and polarization of the fundamental propagating modes can all be effectively tailored under different bias voltages. Different device functionalities, including optical amplitude/phase modulators and polarizers, are ascribed into the devising of the effective mode index. A comprehensive analysis and unified design scenarios upon waveguide geometries are summarized, with fabrication robustness and moderate process complexity. Moreover, design examples are manifested. We report a TM-mode-based phase modulator, achieving a π phase shift within an active length of 49.2 μm with dual graphene layers. A feasible polarization-independent amplitude modulator is also demonstrated, where the discrepancy of the imaginary parts of the effective mode index between the two fundamental modes is kept at an order of 10−5 over a broad wavelength range from 1.35 to 1.65 μm.

Effect of Moisture Content on Power Generation in Dual Graphene Anode Compost Solid Phase Microbial Fuel Cells (DGACSMFCs)

Moisture content which affects the decomposition of organic material is one of composting parameters. The optimum moisture content indicates the higher power generation. This research aims to determine the optimum moisture content toward power density during the composting process in DGACSMFCs. The reactor was designed with dual graphene anode placed on the base and a half of reactor height in 2 L effective volume. Moisture content was varied at 40%; 50%; 60%; with 4 turning frequency, C/N ratio 30:1, and the mixed waste-leaves litter and canteen based food waste, during 23 days of the observation time. Other parameters of the composting process such as pH, temperature, C-Organic, N-Total, P-Total, and K-Total were also observed as control parameters. The result shows that the optimum moisture content is 60% with power density 17.74 mW/m2, and the final compost characteristics are meet the compost requirement based on SNI 19-7030-2004 about the specification of compost from domestic waste..

Enhanced performance of microbial fuel cell with in situ preparing dual graphene modified bioelectrode

This study proposed a three-step method to prepare dual graphene modified bioelectrode (D-GM-BE) by in situ microbial-induced reduction of GO and polarity reversion in microbial fuel cell (MFC). Both graphene modified bioanode (GM-BA) and biocathode (GM-BC) were of 3D graphene/biofilm architectures; the viability and thickness of microbial biofilm decreased compared with control bioelectrode (C-BE). The coulombic efficiency (CE) of GM-BA was 2.1 times of the control bioanode (C-BA), which demonstrated higher rate of substrates oxidation; the relationship between peak current and scan rates data meant that GM-BC was of higher efficiency of catalyzing oxygen reduction than the control biocathode (C-BC). The maximum power density obtained in D-GM-BE MFC was 122.4±6.9mWm−2, the interfacial charge transfer resistance of GM-BA and GM-BC were decreased by 79% and 75.7%. The excellent electrochemical performance of D-GM-BE MFC was attributed to the enhanced extracellular electron transfer (EET) process and catalyzing oxygen reduction.

Bacterial community shift and improved performance induced by in situ preparing dual graphene modified bioelectrode in microbial fuel cell

Dual graphene modified bioelectrode (D-GM-BE) was prepared by in situ microbial-induced reduction of graphene oxide (GO) and polarity reversion in microbial fuel cell (MFC). Next Generation Sequencing technology was used to elucidate bacterial community shift in response to improved performance in D-GM-BE MFC. The results indicated an increase in the relative ratio of Proteobacteria, but a decrease of Firmicutes was observed in graphene modified bioanode (GM-BA); increase of Proteobacteria and Firmicutes were observed in graphene modified biocathode (GM-BC). Genus analysis demonstrated that GM-BE was beneficial to enrich electrogens. Typical exoelectrogens were accounted for 13.02% and 8.83% in GM-BA and GM-BC. Morphology showed that both GM-BA and GM-BC formed 3D-like graphene/biofilm architectures and revealed that the biofilm viability and thickness would decrease to some extent when GM-BE was formed. D-GM-BE MFC obtained the maximum power density by 124.58±6.32mWm−2, which was 2.34 times over C-BE MFC.

Light emission enhancement from ZnO nanostructured films grown on Gr/SiC substrates

We report on the application of a single layer graphene substrates for the growth of polycrystalline ZnO films with advanced light emission properties. Unusually high ultraviolet (UV) and visible (VIS) photoluminesce was observed from the ZnO/Gr/SiC structures in comparison to identical samples without graphene. The photoluminescence intensity depends non-monotonically on the films thickness, reaching its maximum for 150 nm thick films. The phenomena observed is explained as due to the dual graphene role: i) the dangling bond free substrate, providing growth of relaxed thin ZnO layers ii) a back reflector active mirror of the Fabry-Perot cavity that is formed. The reported results demonstrate the potential of two-dimensional carbon materials integration with light emitting wide band gap semiconductors and can be of practical importance for the design of future optoelectronic devices.

Effective medium approach to electron waves: Graphene superlattices

We develop an effective medium approach to characterize the propagation of matter waves in periodic structures, such as graphene or semiconductor superlattices. It is proven that the time evolution of the states that are not more localized in space than the characteristic period of the structure can be described exactly through an effective Hamiltonian, and that the electronic band structure of the system can be exactly determined from the effective Hamiltonian. As an illustration of the application of the method, we characterize the mesoscopic response of graphene superlattices. It is shown that these structures may be described using simply two effective parameters: a dispersive potential, and an anisotropy tensor that characterizes the pseudospin. Our model predicts that a graphene superlattice characterized by an indefinite anisotropy tensor - such that the eigenvalues of the tensor have opposite signs - may permit the perfect tunneling of all the stationary states with a specific value of the energy when it is paired with a dual graphene superlattice with positive definite anisotropy tensor.