Search

Highly organised arrangements of vertically aligned nanostructures are crucial foundational elements in creating versatile devices. Vertically aligned ZnO nanorods (NRs) offer many remarkable applications in electronics, optoelectronics, and electromechanical nanodevices. This review examines recent advancements in synthesising arrays of ZnO nanorods. This manuscript explores the significance of vertically aligned ZnO nanorods in creating versatile devices. It discusses the properties of vertical ZnO nanorods, including their high aspect ratio, large surface area, tunable optical properties, piezoelectricity, chemical stability, and biocompatibility. Recent methods for synthesising vertically aligned ZnO nanorods are detailed, such as using colloidal lithography and a sol-gel-prepared ZnO seed layer. Various studies highlight the controlled growth of ZnO nanorods through top-down fabrication approaches like nanoimprint lithography, electron beam lithography, colloidal lithography, and laser interference lithography, followed by hydrothermal methods. It also includes nanostructure growth using a nanoporous polycarbonate template via electrodeposition. These nanofabrication techniques offer simplicity, uniformity across large wafer-scale areas, and the ability to precisely control the growth of vertical ZnO nanorods, which holds potential for the fabrication of high-performance devices. The last chapter highlights various potential applications of vertically aligned ZnO nanorods, including energy conversion, optoelectronics, sensors, bio-medics, and environmental remediation. [ABSTRACT FROM AUTHOR]

Thermal interface materials (TIMs) have emerged as a potential material for heat dissipation in the cooling system due to their good materials in heat transfer and help protect devices from damage. The main challenge of TIMs is the lower thermal conductivity of materials and poor surface contact, resulting in high internal thermal resistance. Therefore, carbon nanotubes (CNTs) are the best candidate due to their good thermal conductivity. However, the method for deposition of CNTs on the substrate involves high operating temperature and produces unwanted impurities. This study introduces electrophoretic deposition due to the convenient process with operation at room temperature, fast deposition time, simple equipment setup and production of fewer impurities. Pristine CNTs were deposited on the nickel-plated copper substrate using a direct current. The deposition yield can be varied by the variation of CNT-solvent concentration (< 1.0 mg CNT/ml) and applied voltage. The interaction between parameters of electrophoretic deposition (EPD) was optimized using Design of Experiment (DOE) software through the response surface method (RSM) to have maximum deposition of CNTs. Field emission scanning electron microscopy (SEM) was performed to analyze the surface morphology of the deposition and observe the maximum thickness of 56.95 µm with 11.0 mg of CNTs deposited on nickel substrate when operated under 175 V applied voltage, 10 min deposition time for 0.50 mg/ml concentration. [ABSTRACT FROM AUTHOR]

The heat transfer performance in materials to remove heat is attained in various designs according to the devices' design. Simulation studies are comprising of heat transfer knowledge in detail suit the theories and applications. This review provides an understanding of the simulation work focusing on the heat transfer in the various design of electronic devices. This discussion begins with a briefing on the simulation principle and current focus. Then, the review continues by explaining various simulation methods that exhibit recent heat transfer analysis. The properties of simulation studies are also summarized in detail to understand the significant properties that impact analysis. The application of simulation in thermal model is looked forward to obtain significant heat transfer improvement and impactful research direction. This review also provides insights into challenges in simulation work with available opportunities to solve the heat transfer issue by understanding fundamental knowledge. [ABSTRACT FROM AUTHOR]

Summary: Thermal interface materials (TIMs) are applied in electronic devices that are involved in heat generation and raising the temperature. The optimization of TIMs is important in heat dissipation to maintain the good performance of devices, low power during operation, and reduced internal damages among small components. The TIMs are inserted between two contact surfaces to enhance thermal conductivity that will reduce the increment of surface temperature in a longer time and facilitates the cooling process with a consistent power supplied to the system with minimum increment. Research on nanomaterials and hybrid materials aims to obtain maximum thermal conductivity and reduce resistance in the devices. However, the suitable fabrication method for achieving good production and performance is still debatable. Therefore, significant fabrication methods have been explored for various materials. This review provides insights into the current work focusing on the materials used in the development of TIMs by various methods. The discussion begins with the introduction of thermal management and the working principles applied in the system. Then, the methods applied for material fabrication into TIMs, including the advantages and disadvantages of the methods, are discussed. Last, the current challenges and opportunities in methods used are discussed to offer new inputs and improvement in method modification for TIMs design. The targeted thermal performance for the industrial market of TIMs for nanomaterial applications is approximately 100 W/mK and 1 × 10−6 m2/WK with lowest power of 100 W. [ABSTRACT FROM AUTHOR]

Summary: The performance of electronic devices, mostly in medical applications, has been investigated to determine whether they meet the requirements of healthcare monitoring and patient's satisfaction. Mobile health monitoring is preferable at present given the current innovations in handheld, wearable, and implantable devices. However, these applications require appropriate thermal management because they are attached directly to the human body and operate for a long period. Moreover, a sophisticated design with functional mobility necessitates proper thermal circulation during the process. This review provides the current research direction for cooling systems, the thermal working principle of wearable and implantable devices, and its implementation on design architecture. Then, the importance of internal and external functional properties in thermal management and their effects on device performance are discussed. Operating temperature is among the most important elements in monitoring thermal performance due to the tendency of tissue and component damages to occur after an increment of only 1°C or 2°C in temperature. Challenges and available solutions for thermal management are listed in detail to improve cooling methods and service to the healthcare field. [ABSTRACT FROM AUTHOR]

Summary: The industrial revolution development of electronic technologies has turned the electronic system into a complicated integration of high‐power density and smart design. The complex integrated design has contributed to the excessive heat generation in electronic devices. Consequently, heat management devices have become crucial in prolonging the lives of devices and components and maintaining their optimal performance. Therefore, the passive heat management treatment through thermal interface materials (TIMs) in the devices is among the best options to remove heat from electronic devices. Carbon nanotubes (CNTs) with high‐thermal conductivity was employed in this study for TIM development by using the simple electrophoretic deposition (EPD) method. The CNTs were synthesized and purified before TIM development. Several analyses, including transmission electron microscopy, thermogravimetric analysis, Raman spectroscopy, and Fourier‐transform infrared, were conducted. Analysis results showed that only 0.03 wt% was retained and carbon content increased up to 97.84% after purification. The purified CNTs were dissolved in a suspension medium with a ratio of 0.5 mg/mL to achieve suspension stability, and a Zetasizer was used for verification. The following three operating parameters of EPD were investigated: (a) range of applied voltage (100‐200 V), (b) deposition time (1‐20 min), and (c) gap between electrodes (10‐20 mm). On the basis of the characterization results, the optimum process condition of EPD was achieved at 175 V, 10 minutes, and 10 mm with 1.6 mg of CNT deposition and 14.14 μm of CNT thickness. The maximum thickness of deposited CNTs was 56.95 μm, producing 27.08 W/m∙K and 2.09 mm2/s of thermal conductivity and diffusivity, respectively. These results indicate the high potential of CNTs in facilitating efficient heat removal in TIM fabrication. [ABSTRACT FROM AUTHOR]

Summary: The performance of allotrope carbon materials has been explored because of their superior properties in energy system applications. This review provides an understanding of the current work focusing on the applications of selected carbon materials in important energy systems, focus on thermal interface materials (TIMs), and fuel cell applications. This article begins with the introduction of TIMs and fuel cell in general working principle and presents details on carbon materials. The discussion focuses on updates from the latest research work and addresses current challenges and opportunities for research toward TIMs and fuel cell applications. The optimum performance of TIMs was seen when thermal conductivity achieved at a maximum of 3000 W (m K)−1 by using vertically aligned carbon nanotubes (CNTs) and a minimum internal thermal resistance of 0.3 mm2 K W−1. Meanwhile for fuel cell, the platinum/CNTs catalyst applied proton exchange membrane fuel cell achieved high power density of 661 mW cm−2 in the presence of Nafion electrolyte membrane. This review provides insights for scientists about the use of carbon materials, especially in energy system applications. [ABSTRACT FROM AUTHOR]

Thermal interface materials (TIM) involve heat removal from electronic devices. It is used to remove heat sink from the heat sources to prolong the operation system of a device. It normally replaces the thermally insulated air between the two surfaces and uses it as a secondary thermal conductive material. The current thermal conductivity of TIM is considered to be a limitation for the development of advance electronic devices. In this study, the performance of carbon nanotubes (CNTs) which were used as TIM was investigated by using electrophoretic deposition method. The deposition of CNTs was varied from one to six layers and the performance of deposition was evaluated. The stable suspension of CNTs in DMF with zeta potential reading of -35.87 mV give rise to a smooth and uniform deposition on nickel plated copper substrate (heat spreader) with the usage of electrophoretic deposition (EPD). Maximum layers of CNTs deposition were obtained at six layers with 56.95 µm of deposition thickness and 11.0 mg of deposition weight. Thermal conductivity was measured using a thermal analyser while the thickness of deposition was observed using scanning electron microscope (SEM). The employment of CNTs improved the heat removal of TIM with thermal conductivity reading of 27.08 W m-1 K-1. Optimisation studies revealed that EPD operated at an applied voltage of 175 V coupled with 10 min deposition time produced a single layer deposition with the thickness of 14.14 µm. [ABSTRACT FROM AUTHOR]

This review article provides a comprehensive overview of the utilization of waste-derived materials in tissue engineering applications. Waste-derived materials that have been transformed into various bio-ceramics and natural polymer materials have exhibited outstanding biocompatibility and biodegradability in tissue engineering applications. Interestingly, using waste-derived materials could significantly contribute to environmental sustainability by reducing waste disposal. Using waste materials significantly increases source availability while minimizing the cost of manufacturing. The desirable properties and potentials of waste materials have created great opportunities for exploring their implementation in tissue engineering. Thus, this review has summarized the recent research on waste materials in terms of the current progress, limitations, and prospects for tissue engineering applications. Image 1 [ABSTRACT FROM AUTHOR]

Summary: Ionic liquids (ILs) are promising solvents for catalytic and electrolyte applications, gas absorption, and extractions in electrochemical systems due to their useful features, such as high conductivity and good thermal, chemical, and electrical stability. This review focuses on incorporating ILs into fuel cell (FC) systems, specifically into two main components of FC (ie, polymer electrolyte membrane and electrocatalyst). In FC, a polymer electrolyte membrane with excellent conductivity and deprived of humidity even at high temperatures must be created for effective early commercialization of this technology. Electrocatalyst performance can also be enhanced with additive materials, such as ILs, thus further improving the entire achievement of FCs. This work discusses the most important reasons for ongoing studies and outlines the current progress in using ILs as a revolutionary form of polymer electrolyte membrane and electrocatalyst. [ABSTRACT FROM AUTHOR]

Summary: Direct liquid fuel cell (DLFC) is one of the leading fuel cell types due to their great features of superior energy density, modest configuration, small size in fuel container, immediate boosting, and effortless storage and carriage. Commercially used liquid fuel types are prepared using alcohols, such as methanol or ethanol, glycol, and acids. DLFCs face great challenges although they are potentially far‐reaching depending on the expensive catalysts and the use of high‐loading catalyst. More questions that should be addressed to ensure excellent DLFC performance include cathode flooding, fuel crossover, numerous side yield production, fuel security, and unverified elongated‐duration robustness. Further studies need to be carried out to ensure the continuous improvement of the quality of DLFCs' performance and their penetration in the commercial market. To date, direct liquid fuel cells made of methanol and ethanol have been successfully produced in commercial scale, but other types of DLFCs are still under study. In this review, introduction to DLFC will be discussed by covering work and commercialization as well as recent progress and challenges encountered. [ABSTRACT FROM AUTHOR]

Summary: Carbon quantum dots (CQD) and graphene quantum dots (GQDs) have been mentioned frequently. They have been selected in recent studies as they have unique and remarkable potential, especially in electrical, optical, and optoelectrical properties. CQD and GQDs have very high chemical and physical stability due to inherent inert carbon material, thus newly recognized as a kind of quantum dots material. Its environmentally friendly, non‐toxic, and naturally inactive nature is also a major attraction for scientists around the world. In this work, CQD and GQDs production methods are discussed in detail, including soft‐template method, hydrothermal method, microwave‐assisted hydrothermal (MAH) method, metal‐catalyzed method, liquid exfoliation method, electron beam lithography method, and others. Additive material has been introduced in CQD and GQDs to increase the ability and performance of CQD and GQDs such as nitrogen, sulfur, chlorine, fluorine, and potassium. In particular, the presence of additive material in CQD and GQDs shows an advantage in terms of energy level, which is very good at achieving specific requirements in properties such as optical, electrical, and optoelectrical. In addition, the existence of functional groups consisting of heteroatoms such as oxygen, nitrogen, sulfur, phosphorus, boron, and so on of zero‐dimensional carbon materials in providing an overabundance of the active electrochemical site for the reaction. The product of CQD and GQDs has various shapes and sizes influenced by several parameters such as synthesis temperature, growth time, source concentration, catalyst, and so on. The application of CQDs and GQDs composites in fuel cells has been clearly and scientifically stated as it has enhanced the performance of fuel cell technology. [ABSTRACT FROM AUTHOR]

This review discusses the impact of alpha‐gallium oxide (α‐Ga2O3) on potential high‐power device applications. To date, there are high requirements for efficient high‐power delivery and low‐power loss device material in power industries. III‐VI oxide semiconductor family, α‐Ga2O3, is recognized as a promising, future power semiconductor material owing to its ultrawide bandgap of 5.3 eV, high breakdown field of 10 MV cm−1, and a large Baliga's figure of merit. A highly expected α‐Ga2O3 power semiconductor electronic device (Schottky barrier diode and field effect transistor) can perform better than conventional semiconductor materials Si, SiC, and GaN. However, there is a lack of research into using mist CVD to cultivate high‐quality α‐Ga2O3 for high‐power devices like FETs and SBDs. Currently, the mist CVD‐grown α‐Ga2O3 thin film power device is still in its early stages, and one of the main reasons for this is defects of the thin film, which impede material electron mobility. The purpose of writing this article is to provide an overview of the development of α‐Ga2O3 heteroepitaxial thin film by the mist CVD process for use in high‐power devices such as Schottky barrier diodes (SBD) and field effect transistors (MOSFET). 1. α‐Ga2O3 α‐Ga2O3. Furthermore, multiple viewpoints highlight the challenges and future trends toward device performance sustainability in a scientific society. [ABSTRACT FROM AUTHOR]

This review provides the recent advances in triglyceride catalytic pyrolysis using heterogeneous dolomite catalysts for upgrading biofuel quality. The production of high-quality renewable biofuels through catalytic cracking pyrolysis has gained significant attention due to their high hydrocarbon and volatile matter content. Unlike conventional applications that require high operational costs, long process times, hazardous material pollution, and enormous energy demand, catalytic cracking pyrolysis has overcome these challenges. The use of CaO, MgO, and activated dolomite catalysts has greatly improved the yield and quality of biofuel, reducing the acid value of bio-oil. Modifications of the activated dolomite surface through bifunctional acid–base properties also positively influenced bio-oil production and quality. Dolomite catalysts have been found to be effective in catalyzing the pyrolysis of triglycerides, which are a major component of vegetable oils and animal fats, to produce biofuels. Recent advances in the field include the use of modified dolomite catalysts to improve the activity and selectivity of the catalytic pyrolysis process. Moreover, there is also research enhancement of the synthesis and modification of dolomite catalysts in improving the performance of biofuel yield conversion. Interestingly, this synergy contribution has significantly improved the physicochemical properties of the catalysts such as the structure, surface area, porosity, stability, and bifunctional acid–base properties, which contribute to the catalytic reaction's performance. [ABSTRACT FROM AUTHOR]

[Display omitted] CO 2 capture strategies have been implemented to address climate change by reducing CO 2 emissions from large-scale sources such as fossil fuel power plants and natural gas upgrading. Deep eutectic solvents (DESs) are a new class of green solvents with good CO 2 affinity, simple synthesis steps, inexpensive raw materials, non-toxic and non-volatile properties. For these reasons, they are a promising platform for CO 2 capture applications and have tremendous untapped potential to enhance the performance of the adsorption and membrane-based separation processes. Unlike existing reviews which have focused on the functionalities of DESs, as well as the physicochemical and CO 2 solubility properties of DESs, this mini-review discusses the integration of DESs with adsorption and membrane processes to evaluate their CO 2 separation performance. Moreover, simulation and computational studies on DES-based systems, including confinement in porous solids and membranes, are discussed. Finally, perspectives on developing DES-based adsorbents and DES-based membranes for the CO 2 separation field are presented. This review provides insight into the potential of integrating DESs with CO 2 capture technologies to enhance the performance of hybrid systems in relation to standalone approaches. [ABSTRACT FROM AUTHOR]

Driven by the depletion of fossil fuels, there is a pressing need for clean alternative fuels for energy applications. Biomass pyrolysis, utilizing biomass as a feedstock, has emerged as a promising sustainable alternative. However, the presence of oxygen-containing compounds and high acidity in the biofuel produced through pyrolysis necessitate further upgrading. Mesoporous catalysts, with their high surface area, tunable pore size, and catalytic activity, have shown great potential in improving the quality of biofuels derived from biomass pyrolysis. This review explores the recent advancements and challenges associated with employing mesoporous catalysts in the upgraded pyrolysis of biomass for biofuel production. It delves into the various types of mesoporous catalysts utilized and the catalytic mechanisms at play during the upgrading process. The review further discusses the progress made and the challenges encountered in the application of mesoporous catalysts. Strategies to enhance catalyst stability and activity, such as catalyst modification and the use of co-catalysts, are also examined. Additionally, the review emphasizes the critical properties of the mesoporous structure for optimal catalyst design. By providing a comprehensive overview of the current state of knowledge, this review serves as a valuable resource for researchers and practitioners interested in the development and application of mesoporous catalysts in pyrolysis for biofuel production. It highlights the promise of mesoporous catalysts while also acknowledging the challenges that need to be addressed for their successful implementation. • Mesoporous structures offer broad applications in catalyst design, particularly for enhancing biofuel quality. • Mesoporous structures can be combined with other materials like metals, metal oxides, and bimetallic compounds, expanding their potential applications. • Incorporating mesopores in hierarchical structures improves uniformity of metal distribution, allows for higher metal loading, and provides a larger reaction area, enhancing catalytic activity. • The use of mesoporous catalysts in pyrolysis upgrading reduces carbon formation, increasing biofuel heating value. [ABSTRACT FROM AUTHOR]

Summary: This review provides a deep insight into the advanced polymer composite developed in fuel cell application. Organic polymer combined with inorganic filler has produced a new material known as a hybrid membrane or composite membrane. This combination has enhanced the various characteristics including conductivity properties, membrane permeability, and stability, cheaper, optimum water retention and mechanical properties. Properties of the hybrid membrane are influenced totally by several factors such as membrane preparation techniques as well as internal properties of particles involved, for example, inorganic fillers such as the size and type of particles, surface alkaline or acidity, shape and formation of networking between the polymer phase. The conventional membrane used in the fuel cell application is Nafion. Nafion potential is undoubtedly in obtains of high conductivity, but it faces some major problems such as CO poisoning, high cost, fuel crossover and water management that needs to be taken seriously. Hybrid composite is seen as an alternative material to addressing problems faced by a conventional membrane but promises even better potential if explored in depth. In this article, all inorganic fillers involved in the production of the composite membranes have been discussed comprehensively. Different types of polymers have been categorized with various fillers. [ABSTRACT FROM AUTHOR]

Highly efficient bio-inspired platinum nanoparticles (Pt NPs) as an electrocatalyst with superior intrinsic kinetics and high performance for methanol oxidation reaction (MOR) derived from green synthesis of bio-waste utilization is of great interest. The bio-inspired Pt NPs were examined for their kinetic parameters in terms of the Tafel plot, exchange current, square root of the scan rate, methanol diffusion coefficient, activation energy (E a), and factors influencing current density. Bio-inspired Pt NPs exhibit a fast kinetic reaction with a low Tafel value of 179 mV dec−1 and exchange current, α = 0.33, compared to commercial Pt black (233 mV dec−1, α = 0.25). The bio-inspired Pt NPs display low activation energy, E a , as the potential increases, indicating improved intrinsic kinetics, and the MOR catalyzed by bio-Pt NPs was discovered to be a diffusion-controlled process. The parametric effect of bio-inspired Pt NPs concentration has a crucial influence on the anisotropic morphological structure and interconnection to the current density (mA mg−1) of MOR. Central Composite Design (CCD) was applied for RSM-based modeling and analyzing the parameter effects, including bio-inspired Pt NPs concentration, methanol concentration, and electrocatalyst loading to optimize the current density. The optimized current density produced by bio-inspired Pt NPs was 640.11 mA mg Pt −1 at ideal conditions of 1.5 mM bio-Pt NPs, 1.05 M CH 3 OH, and 2.14 mg. Ultimately, the passive DMFC single-cell powered by bio-inspired Pt NPs generates power density with P max of 5.70, 6.67, and 8.28 mW cm−2 at 25, 80, and 100 °C. Thus, bio-inspired Pt NPs derived from green synthesis pathways and biomass-mediated extract have been proven to be viable and sustainable anode electrocatalysts for utilization in the energy conversion of renewable energy with outstanding performance. [Display omitted] • Biomass waste offers facile, economic, and green synthesis pathway for bio-inspired Pt NPs. • Bio-inspired Pt NPs endowed superior in MOR due to improved intrinsic kinetics activities. • Tuneable bio-inspired Pt NPs concentration has structure–activity relationship in MOR. • The RSM-CCD model optimization validates experimental design in MOR using bio-inspired Pt NPs. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) is a promising wide-band-gap semiconductor material for UV optical detectors and high-power transistor applications. The fabrication of p-type Ga2O3 is a key problem that hinders its potential for realistic power applications. In this paper, pure α-Ga2O3 and Ca-doped α-Ga2O3 band structure, the density of states, charge density distribution, and optical properties were determined by a first-principles generalized gradient approximation plane-wave pseudopotential method based on density functional theory. It was found that calcium (Ca) doping decreases the bandgap by introducing deep acceptor energy levels as the intermediate band above the valence band maximum. This intermediate valence band mainly consists of Ca 3p and O 2p orbitals and is adequately high in energy to provide an opportunity for p-type conductivity. Moreover, Ca doping enhances the absorptivity and reflectivity become low in the visible region. Aside, transparency decreases compared to the pure material. The optical properties were studied and clarified by electrons-photons interband transitions along with the complex dielectric function's imaginary function. [ABSTRACT FROM AUTHOR]

This article provides an overview of the structural and physicochemical properties of stable carbon-based nanomaterials and their applications as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The research community has long sought to harvest highly efficient third-generation DSSCs by developing carbon-based CEs, which are among the most important components of DSSCs. Since the initial introduction of DSSCs, Pt-based electrodes have been commonly used as CEs owing to their high-electrocatalytic activities, thus, accelerating the redox couple at the electrode/electrolyte interface to complete the circuit. However, Pt-based electrodes have several limitations due to their cost, abundance, complicated facility, and low corrosion resistance in a liquid electrolyte, which further restricts the large-area applications of DSSCs. Although carbon-based nanostructures showed the best potential to replace Pt-CE of DSSC, several new properties and characteristics of carbon-CE have been reported for future enhancements in this field. In this review, we discuss the detailed synthesis, properties, and performances of various carbonaceous materials proposed for DSSC-CE. These nano-carbon materials include carbon nanoparticles, activated carbon, carbon nanofibers, carbon nanotube, two-dimensional graphene, and hybrid carbon material composites. Among the CE materials currently available, carbon-carbon hybridized electrodes show the best performance efficiency (up to 10.05%) with a high fill factor (83%). Indeed, up to 8.23% improvements in cell efficiency may be achieved by a carbon-metal hybrid material under sun condition. This review then provides guidance on how to choose appropriate carbon nanomaterials to improve the performance of CEs used in DSSCs. [ABSTRACT FROM AUTHOR]