Exploring the Potential of Two-Dimensional Materials for Innovations in Multifunctional Electrochromic Biochemical Sensors: A Review

In this review, the current advancements in electrochromic sensors based on two-dimensional (2D) materials with rich chemical and physical properties are critically examined. By summarizing the current trends in and prospects for utilizing multifunctional electrochromic devices (ECDs) in environmental monitoring, food quality control, medical diagnosis, and life science-related investigations, we explore the potential of using 2D materials for rational design of ECDs with compelling electrical and optical properties for biochemical sensing applications.Comment: 37 pages, 9 Figures, 2 table

Evaluating the potential of two-dimensional materials for innovations in multifunctional electrochromic biochemical sensors: a review

In this review, the current advancements in electrochromic sensors based on two-dimensional (2D) materials with rich chemical and physical properties are critically examined. By summarizing the current trends in and prospects for utilizing multifunctional electrochromic devices (ECDs) in environmental monitoring, food quality control, medical diagnosis, and life science-related investigations, we explore the potential of using 2D materials for rational design of ECDs with compelling electrical and optical properties for biochemical sensing applications.Supramolecular & Biomaterials Chemistr

Two-dimensional graphitic carbon nitride (g-C3N4) nanosheets and their derivatives for diagnosis and detection applications

The early diagnosis of certain fatal diseases is vital for preventing severe consequences and contributes to a more effective treatment. Despite numerous conventional methods to realize this goal, employing nanobiosensors is a novel approach that provides a fast and precise detection. Recently, nanomaterials have been widely applied as biosensors with distinctive features. Graphite phase carbon nitride (g-C3N4) is a two-dimensional (2D) carbon-based nanostructure that has received attention in biosensing. Biocompatibility, biodegradability, semiconductivity, high photoluminescence yield, low-cost synthesis, easy production process, antimicrobial activity, and high stability are prominent properties that have rendered g-C3N4 a promising candidate to be used in electrochemical, optical, and other kinds of biosensors. This review presents the g-C3N4 unique features, synthesis methods, and g-C3N4-based nanomaterials. In addition, recent relevant studies on using g-C3N4 in biosensors in regard to improving treatment pathways are reviewed

Emerging Low Detection Limit of Optically Activated Gas Sensors Based on 2D and Hybrid Nanostructures.

Gas sensing is essential for detecting and measuring gas concentrations across various environments, with applications in environmental monitoring, industrial safety, and healthcare. The integration of two-dimensional (2D) materials, organic materials, and metal oxides has significantly advanced gas sensor technology, enhancing its sensitivity, selectivity, and response times at room temperature. This review examines the progress in optically activated gas sensors, with emphasis on 2D materials, metal oxides, and organic materials, due to limited studies on their use in optically activated gas sensors, in contrast to other traditional gas-sensing technologies. We detail the unique properties of these materials and their impact on improving the figures of merit (FoMs) of gas sensors. Transition metal dichalcogenides (TMDCs), with their high surface-to-volume ratio and tunable band gap, show exceptional performance in gas detection, especially when activated by UV light. Graphene-based sensors also demonstrate high sensitivity and low detection limits, making them suitable for various applications. Although organic materials and hybrid structures, such as metal-organic frameworks (MoFs) and conducting polymers, face challenges related to stability and sensitivity at room temperature, they hold potential for future advancements. Optically activated gas sensors incorporating metal oxides benefit from photoactive nanomaterials and UV irradiation, further enhancing their performance. This review highlights the potential of the advanced materials in developing the next generation of gas sensors, addressing current research gaps and paving the way for future innovations

Three-dimensional nitrogen-doped graphene supported molybdenum disulfide nanoparticles as an advanced catalyst for hydrogen evolution reaction

An efficient three-dimensional (3D) hybrid material of nitrogen-doped graphene sheets (N-RGO) supporting molybdenum disulfide (MoS2) nanoparticles with high-performance electrocatalytic activity for hydrogen evolution reaction (HER) is fabricated by using a facile hydrothermal route. Comprehensive microscopic and spectroscopic characterizations confirm the resulting hybrid material possesses a 3D crumpled few-layered graphene network structure decorated with MoS2 nanoparticles. Electrochemical characterization analysis reveals that the resulting hybrid material exhibits efficient electrocatalytic activity toward HER under acidic conditions with a low onset potential of 112 mV and a small Tafel slope of 44 mV per decade. The enhanced mechanism of electrocatalytic activity has been investigated in detail by controlling the elemental composition, electrical conductance and surface morphology of the 3D hybrid as well as Density Functional Theory (DFT) calculations. This demonstrates that the abundance of exposed active sulfur edge sites in the MoS2 and nitrogen active functional moieties in N-RGO are synergistically responsible for the catalytic activity, whilst the distinguished and coherent interface in MoS 2 /N-RGO facilitates the electron transfer during electrocatalysis. Our study gives insights into the physical/chemical mechanism of enhanced HER performance in MoS2/N-RGO hybrids and illustrates how to design and construct a 3D hybrid to maximize the catalytic efficiency

Room temperature conductive type metal oxide semiconductor gas sensors for NO2 detection

peer reviewe

2D materials based heterostructures : a lithography free method.

Many properties of Two-dimensional (2D) materials are vastly different from those of their 3D counterparts. A large family of 2D materials ranging from gapless graphene to metallic NbSe2 (also superconducting), semiconducting MoS2, and insulating hexagonal boron nitride (h-BN) possessing a broad range of exciting new properties have emerged in recent years. Moreover, 2D materials provide the perfect platform to create laterally and vertically stacked heterostructures with intriguing properties. The physics of 2D materials based heterostructures is extremely interesting and novel 2D-heterostructured devices including tunneling diodes, tunneling transistors, photovoltaic cells, and light-emitting diodes have started to emerge. In this work, we developed a novel lithography-free technique for the fabrication of 2D material-based electrical devices. We fabricated few-layer and multi-layer WS2 devices using a transmission electron microscope (TEM) grid as a shadow mask, and its transport characteristics were studied by electrical measurements. WS2 samples were synthesized by first depositing WO3 followed by sulfurization and characterized by scanning tunneling microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy. Hydrazine adsorption on WS2 was studied by measuring the electrical resistances during adsorption (exposing to hydrazine vapor) and subsequent desorption (by pumping). WS2 sample consisting of two layers showed a decrease of resistance upon exposure to hydrazine vapor and showed complete reversibility upon pumping. WS2 sample with three layers showed a decrease of resistance during exposure but showed only partial recovery during desorption. In contrast, multi-layered (12 layers) WS2 sample showed an initial decrease followed by a continued increase of the resistance upon exposure to hydrazine with little or no reversibility upon pumping. The charge transfer from N2H4 to WS2 is believed to be responsible for the decrease of the resistance. Trapping of N2H4 molecules within the multilayers of WS2 causing charge redistribution and possible chemical reactions is believed to be responsible for the increase in resistance during the adsorption and complete irreversibility of resistance during desorption. The experimental results are explained with the help of computational calculations carried out by employing the density functional theory (DFT) framework, as implemented in the Vienna Ab-initio Simulation Package (VASP). Next, we extended our lithography-free technique for the fabrication of two-dimensional (2D) material based heterostructures. We fabricated graphene-WS2 heterostructured devices again using a TEM grid as a shadow mask. Graphene was directly deposited on a Si/SiO2 substrate by radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD). WS2 was synthesized as before. The temperature dependence of the resistance and magnetoresistance are measured for graphene, WS2, and graphene-WS2 heterostructure. At low temperatures, the transport was found to follow the variable-range hopping (VRH) process, where logarithmic R exhibits a �−1/3 temperature dependence, an evidence for the 2D Mott VRH transport. The measured low-field magnetoresistance also exhibits a quadratic magnetic field dependence ~�2, consistent with the 2D Mott VRH transport. Finally, a lithography-free technique was developed to fabricate Graphene/h-BN/Graphene tunnel junctions. Graphene and h-BN were directly deposited on a Si/SiO2 substrate by RF-PECVD using CH4 and ammonia borane as the precursors respectively. Tunnel diodes with varying barriers were fabricated by tuning the thickness of the h-BN layer thickness. The tunneling current was found to scale exponentially with the tunnel barrier thickness

Ti3AlC2 MAX Phase Modified Screen-Printed Electrode for the Fabrication of Hydrazine Sensor

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1–50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology.Authors gratefully acknowledged Deputyship for Research and Innovation, ‘Ministry of Education’ in Saudi Arabia for funding this research (IFKSUOR3-465-2).Deputyship for Research and Innovation, ‘Ministry of Education’ in Saudi Arabi

Preparation, Structural Characterization, and Application of Reduced Graphene Oxide-Based Hybrid Materials

Department of Energy EngineeringHybrid nanomaterials have the advantages of their individual components while also exhibiting new properties for practical applications. Many approaches have been studied for the synthesis of hybrid materials composed of metals, metal oxides, metal chalcogenides, polymers, and carbon materials. To apply these to practical applications such as field-effect transistors (FET), photovoltaic devices, and sensors, the synthesis of hybrid materials and fundamental study to understand their unexpected properties are very important. In addition, comprehension of the interaction at the interface between the two materials is needed. This paper discussed our approaches to develop new hybrid materials by means of functionalization. This thesis can be divided into two major parts for graphene-based hybrid materials: the functionalization of reduced graphene oxide (rGO) and rGO/TMD hybrid materials. The first part describes functionalization related to graphene oxide (GO) and rGO. Although these are the major applications of graphene, it is worth noting that graphene itself has a zero band-gap as well as chemical inertness, which weaken its competitive strength in the field of semiconductors and sensors. Therefore, tuning the electrical properties of graphene is important. Here, to control the electrical properties, the assembly of rGO and fullerene (C60) into hybrid (rGO/C60) wires was performed by π-π interaction between rGO and C60. Structural characterization and possible applications of the interaction between rGO and C60 will be discussed. In addition, amine-functionalized rGO, which has an n-doping effect in FET, is introduced. The mechanism of the doping effect and a facile method for the fabrication of rGO FET with self-assembled monolayers (SAMs) will also be discussed. The second part focuses on the synthesis of transition-metal dichalcogenide (TMD)-functionalized rGO and its electrocatalytic activity in the hydrogen evolution reaction (HER). Relatively, little is known about the synthesis of hybrid materials with TMD and rGO. In addition, the application of bulk TMDs for hydrogen evolution has been ignored for a long time owing to their poor activity. However, these materials, in particular 2D MoS2 and WS2 nanosheets, are starting to gain attention for use as catalysts in HER, alongside the explosive interest in graphene and other 2D materials. Therefore, synthesis of WS2/rGO hybrid sheets and their electrocatalytic activity levels have been demonstrated. Furthermore, we report the synthesis of a hybrid of CoS2/rGO, which has not been reported, and its electrocatalytic activity in HER.ope