Good Conductivity Research Articles

High-performance and ultra-robust triboelectric nanogenerator based on hBN nanosheets/PVDF composite membranes for wind energy harvesting

Triboelectric nanogenerator (TENG) is a novel energy technology that converts high-entropy mechanical energy from the environment into electrical energy using triboelectrification and electrostatic induction effects. However, the low surface charge density and easy wear of traditional triboelectric materials are bottlenecks for their practical applications. Here, a remarkable triboelectric properties, superior mechanical properties, exceptional wear resistance, and high thermal conductivity hexagonal boron nitride nanosheets (hBNNS)/ polyvinylidene difluoride (PVDF) composite negative triboelectric material is developed. The inclusion of hBNNS as an electron acceptor and nucleating agent not only effectively boosted the surface charge density (711 μC/m2) and mechanical characteristics of the composite membrane, but also the friction coefficient (COF) and thermal conductivity of the 2 wt% hBNNS/PVDF composite membrane decreased by 28.6 % and increased by 22.2 % compared to the PVDF matrix, respectively. The optimized TENG delivers a peak voltage of 434 V, a current of 53 μA, and a power of 4.84 mW. Furthermore, it exhibits exceptional ultra-robust, enabling continuous operation for 72 h at a wind speed of 17.5 m/s while maintaining performance above 90.6 %. Additionally, the TENG is capable of effectively powering a smart hygrothermograph and realizing wireless real-time monitoring, or directly lit up 102 white LEDs in a serial connection. This work addresses the challenges of low output performance and limited lifespan in TENG from a material perspective, providing a valuable reference method for the design of negative triboelectric materials with high surface charge density, good mechanical properties, low COF, and high thermal conductivity.

Al(Si)/Al2O3 and NiAl(Si)/Al2O3 co-continuous composites obtained by low temperature reactive metal penetration of dense silica preforms

Interpenetrating network Al(Si)/Al2O3 composites, obtained by a reactive metal penetration process, where pure aluminum metal reacts with a dense amorphous silica preform, are an interesting class of metal/ceramic composites, with two continuous networks of metal (Al-Si alloy) and ceramic (Al2O3). These composites have high stiffness and hardness, while retaining acceptable toughness and good thermal and electrical conductivity, and can be used in wear or thermal management applications. A second infiltration step with nickel allows to substitute the Al(Si) alloy with an intermetallic, obtaining an interpenetrating network NiAl(Si)/Al2O3 composite, with very high hardness and melting point. While in the standard process the temperature for obtaining the Al(Si)/Al2O3 composites is in the 1100–1200 °C range, in this paper we studied instead the 700–1000 °C temperature range and its effect on the microstructure of the final NiAl(Si)/Al2O3 composite. After the first infiltration step, the microstructure of Al(Si)/Al2O3 composites depends on both temperature and time of the treatment. At 700–800 °C and for reaction time of 1–2 h, the grain size is completely sub-micrometric. When temperature and time of reaction increase, islands with a coarser microstructure, of micrometric size, form, reaching a fully micrometric coarser microstructure at 1100–1200 °C. The islands formation is due to the transformation from transition aluminas, formed at low temperature and low reaction time, to α-alumina, while at high temperature α-alumina forms directly. In a second step, the Al(Si) metal network was replaced with an intermetallic one, by contacting the composite with liquid nickel, that reacted with the Al(Si) alloy forming an Al-Ni-Si intermetallic. The temperature and duration of the first infiltration step strongly influences not only the microstructure of the Al(Si)/Al2O3 composite but also of the final NiAl(Si)/Al2O3 one, that is finer when the first step (reaction of aluminum with silica) occurs at lower temperature.

A high‐entropy (Er0.25Y0.25Ho0.25Yb0.25)2Si2O7 ceramic with good thermal properties and water‐vapor corrosion resistance

AbstractA high‐entropy rare‐earth disilicate (Er0.25Y0.25Ho0.25Yb0.25)2Si2O7 (hereinafter referred to as (EYHY)2Si2O7) ceramic was synthesized by a heat treatment process combined with spark plasma sintering. According to the experimental results, (EYHY)2Si2O7 presents good phase stability and low thermal conductivity ([1.48–2.35] W∙m−1∙K−1) from room temperature to 1200°C. Its coefficient of thermal expansion is (3.89–5.32) × 10−6 K−1 from 200 to 1400°C, similar to SiC‐based materials ([4.5–5.5] × 10−6 K−1). Due to the multiple doping effects, (EYHY)2Si2O7 exhibits outstanding corrosion resistance performance in water‐vapor corrosion tests. Its weight loss is 1.79 mg/cm2 after corrosion at 1600°C for 30 h in the presence of 50% H2O‐50% O2, which is lower than the corresponding four single components Re2Si2O7 (Er2Si2O7, Y2Si2O7, Ho2Si2O7, and Yb2Si2O7) under the same conditions. Therefore, high‐entropy (EYHY)2Si2O7 ceramics are regarded as potential environmental barrier coatings materials for SiC ceramic matrix composites.

Conformal SnO2 and NiOx charge transport layers for pragmatic air-processed perovskite solar cells

The industrialization of perovskite (PVK) solar cells (PSCs) necessitates simple manufacturing, cheapness, nontoxicity, high efficiency, and stability. We report an air-processed lead halide PSCs with cheap, nontoxic, stable NiOx and SnO2 as the hole and electron transport layers separately, to meet all the above commercial requests. By preparing the NiOx (water-dispersible) and SnO2 (oil-dispersible) quantum dots (QDs) with good conductivity and energy band matched well with that of PVK, we fabricate inverted PSCs (ITO/NiOx/PVK/SnO2/Ag) with efficiency up to 20.1/14.6% for active areas of 0.0707/1 cm2, under 1 sun simulated illumination with enhanced UV light ratio. The UV-light resistant PSCs reported here will impel their application in the high altitude areas with strong UV light. Importantly, the monodisperse size and dominant (110) plane of SnO2 QDs achieved by controlling the solvothermal parameters, realize the conformal deposition and defect prevention of SnO2, respectively, thus improving the PSC efficiency and stability.

Coupled Lattice‐Expanded Ni and MoO2 Array for Efficient Alkaline Hydrogen Evolution

AbstractTransition metal oxides have attracted much attention due to their good electrical conductivity, high chemical stability, and easy electronic structure modulation. However, it is still a great challenge to solve the problems of sluggish reaction kinetics and high overpotential in the alkaline hydrogen evolution reaction (HER) due to their poor intrinsic activity. Herein, a lattice‐expanded Ni‐decorated MoO2 array (Ni‐MoO2‐700) catalyst is prepared for the alkaline HER. Unlike most of the reported literature, the decoration of metal heteroatoms may lead to lattice expansion of the carrier catalyst. In contrast, lattice expansion of Ni is also achieved by adjusting the annealing temperature in this work. The Ni‐induced lattice‐expanding effect can not only modulate the electronic structure of the catalyst but also accelerate electron transfer during the reaction, thus increasing its intrinsic activity for the HER. As a result, Ni‐MoO2‐700 exhibits significantly enhanced catalytic activity with an overpotential of 74.9 mV at 10 mA cm−2 in 1.0 m KOH, which is far superior to that of most of the reported advanced Ni‐ and Mo‐based materials. This work provides deep intrinsic insight and a great opportunity to design efficient transition metal oxide catalysts for the alkaline HER.

Review of Wear and Mechanical Characteristics of Al-Si Alloy Matrix Composites Reinforced with Natural Minerals

Al-Si alloys are vital in the aerospace and automotive industries due to their high strength-to-weight ratio, excellent ductility, and superior corrosion resistance. These properties, along with good thermal conductivity, low thermal expansion, and enhanced wear resistance due to silicon, make them ideal for lightweight, high-performance components like engine parts exposed to harsh conditions and thermal cycling. In recent years, the development of aluminium metal matrix composites using Al-Si alloys as the base material has gathered significant attention. These composites are engineered by integrating various reinforcing particles into the aluminium matrix, which results in remarkable improvements in the wear resistance, hardness, and overall mechanical performance of the material. The stir casting process, a well-established and cost-effective method, is frequently employed to ensure a uniform distribution of these reinforcing particles within the matrix. This review delves into the influence of different types of reinforcing particles on the properties of Al-Si alloy-based AMCs. The incorporation of these reinforcements has been shown to significantly enhance wear resistance, reduce friction, and improve the overall strength and toughness of the composites, making them ideal candidates for high-performance applications in the automotive and aerospace sectors. Moreover, this review highlights the challenges associated with the fabrication of these composites, such as achieving a homogeneous particle distribution and minimizing porosity. It also discusses the latest advancements in processing techniques aimed at overcoming these challenges. Additionally, this review addresses the potential environmental and economic benefits of using natural reinforcements, which not only reduce material costs but also contribute to sustainable manufacturing practices.

Flexible Highly Thermally Conductive PCM Film Prepared by Centrifugal Electrospinning for Wearable Thermal Management

Personal thermal management materials integrated with phase-change materials have significant potential to satisfy human thermal comfort needs and save energy through the efficient storage and utilization of thermal energy. However, conventional organic phase-change materials in a solid state suffer from rigidity, low thermal conductivity, and leakage, making their application challenging. In this work, polyethylene glycol (PEG) was chosen as the phase-change material to provide the energy storage density, polyethylene oxide (PEO) was chosen to provide the backbone structure of the three-dimensional polymer network and cross-linked with the PEG to provide flexibility, and carbon nanotubes (CNTs) were used to improve the mechanical and thermal conductivity of the material. The thermal conductivity of the composite fiber membranes was boosted by 77.1% when CNTs were added at 4 wt%. Water-resistant modification of the composite fiber membranes was successfully performed using glutaraldehyde-saturated steam. The resulting composite fiber membranes had a reasonable range of phase transition temperatures, and the CC4PCF-55 membranes had melting and freezing latent heats of 66.71 J/g and 64.74 J/g, respectively. The results of this study prove that the green CC4PCF-55 composite fiber membranes have excellent flexibility, with good thermal energy storage capacity and thermal conductivity and, therefore, high potential in the field of flexible wearable thermal management textiles.

Thermal performance of a novel composite phase change material for solar-assisted air source heat pump packed bed thermal energy storage application

The thermal properties of the heat storage medium in the solar-assisted air source heat pump (SAASHP) systems must be aligned with the system’s heat generation temperature while satisfying the heat demand. In this study, a novel composite phase change material (CPCM) for efficient heat storage in SAASHP systems was developed. Our investigation revealed that the incorporation of 8 wt% KNO3, 1.5 wt% thickener, and 1.0 wt% Al2O3 nanoparticles into sodium acetate trihydrate resulted in the manifestation of desirable properties suitable for SAASHP systems. The compound exhibited a suitable melting point of 48.66 °C, high latent heat of 235.97 kJ/kg, low supercooling degree of 2.25 °C, and good thermal conductivity of 0.905 W/(m·K). Furthermore, the novel CPCM demonstrated exceptional thermal stability, with only an 8.64 % loss of latent heat after undergoing 200 cycles, while maintaining a supercooling degree within a range of 6 °C for each cycle. Moreover, molecular dynamics simulation results further indicated that the presence of KNO3 weakened the interaction between CH3COONa molecules and water molecules, leading to a reduction of the melting point. Additionally, numerical analysis revealed that the total heat storage capacity and exergy storage capacity of the packed bed thermal energy storage (PBTES) system filled with the novel CPCM are 358.8 MJ and 25.1 MJ, respectively. With an increase in the heating power of the SAASHP system from 10 kW to 30 kW, the cycle heat storage time of the PBTES system can decrease by 38.8 %, while an increase in the flow rate from 2 m3/h to 6 m3/h can reduce the time by 26.3 %. These findings have significant implications for the selection and composition design of thermal storage materials in SAASHP systems.

Improving a shell-tube latent heat thermal energy storage unit for building hot water demand using metal foam inserts at a constant pumping power

The phase transition heat transfer during the melting and solidification processes of phase change materials (PCMs) was modeled in a shell-tube thermal energy storage unit. For the first time, special attention was dedicated to the heat transfer enhancement on the heat transfer fluid (HTF) side by placing metal foam (MF) inserts in the HTF tube. The MF inserts on the HTF side were placed next to the fin bases to produce the maximum heat transfer enhancement. A two-temperature local thermal non-equilibrium model was applied to accurately model the transient heat transfer in the MF domains. To perform a fair heat transfer analysis and consider the hydrodynamic aspects of heat transfer, the pumping power for driving the HTF fluid was kept fixed. The finite element method with automatic time-step control was used to integrate the model equations. Results show that the insertion of the MF in the HTF tube enhances conduction heat transfer but reduces flow for a constant pump power. Using a small amount of MF provides a good flow rate and a convective heat transfer while using a large amount of MF provides good conduction heat transfer but a poor flow rate and convection. A moderate amount of MF inserts results in poor conduction and a poor flow rate, notably increasing the phase transition time. A 5 % MF insert could provide about a 13 % shorter solidification time compared to a 25 % MF insert. Thus, a well-designed and engineered MF insert configuration on the HTF side can reduce the phase transition time and improve the energy storage power.

Polymerizable deep eutectic solvent enables flexible gel formation for motion sensor and anti-UV film

Specific applications of gels can raise multiple demands, including low cost, elasticity, adaptability to wide temperature ranges, conductivity, and reduced hazards, thereby presenting diverse challenges for one material. Deep eutectic solvents (DESs) offer unexpected solutions to tackling the challenging task. Here, we mixed anhydrous diallyldimethylammonium chloride (DMDAAC) and urea to synthesize a polymerizable DES with a wide range of solubility. It can polymerize to form versatile DES gel upon photoinitiation. The gel exhibited high transparency (∼94 %), a wide range of temperature tolerance (−40 ∼ 100 °C), outstanding elastic properties (ε > 2400 %), good conductivity (0.05 mS·cm−1) and self-healing capability. The pristine gel film was successfully applied to motion sensors, while the DES gel with lignin was also employed as an elastic anti-UV film. Moreover, its water-solubility and non-hazardous compositions suggest the minimize environmental impact of the DES gel. This polymerizable DES can not only boost the development of electronic devices like motion sensors, but also inspire more creative ideas in promising applications of DESs and DES gels.

Flexible and transparent leaf-vein electrodes fabricated by liquid film rupture self-assembly AgNWs for application of heaters and pressure sensors

The leaf veins with hierarchically interconnected network structures have great potential as self-assembly templates for transparent and flexible electrodes. In this paper, a liquid membrane ruptured assisted AgNWs self-assembly method was adopted to obtain conductive veins, which show a low sheet resistance of 3.6Ω/□ and a high transparency of 79 % at a minimal materials waste. The figure of merit of conductive veins was as high as 433Ω-1 and can be further increased by increasing the number of soaking because the light transmittance is nearly immune to the AgNWs layer number. The veins maintained a good electrical conductivity even after bending 10,000 times at a 2 mm radius of curvature and exhibited a good corrosion resistance under harsh conditions. Heaters based on the conductive veins are shown as application examples. A high temperature of 104 °C was achieved at a low voltage of 2 V, which is enough to heat cold water. They still have good heating properties even in the bending state or tensile state. Furthermore, pressure sensors based on the conductive veins were fabricated as examples of wearable devices. The sensor exhibits a high sensitivity of 3.8 kPa−1 in the low-pressure range (0–15 kPa) and 17.4 kPa−1 in the high pressure range (15–50.96 kPa). It can monitor human actions such as finger bending, finger taping, throat swallowing and wrist pulse in real-time, which has promising potential for motion monitoring and information encryption applications.

ZnO-NaNO3 nanocomposites for solar thermal energy storage systems

High-temperature phase change materials (PCMs) with good energy storage density and thermal conductivity are needed to utilize solar thermal energy effectively to meet industrial thermal energy demands. Composite PCMs containing a material of higher thermal conductivity and an inorganic high-temperature PCM can be explored to meet these requirements. Accordingly, a high-temperature, composite inorganic PCM (ZnO-NaNO3) with enhanced thermophysical properties was prepared, and its energy storage potential was investigated experimentally. A maximum thermal conductivity enhancement of 22.7% was achieved at 200 °C for 2 wt% ZnO-NaNO3 nanocomposite. The increase in thermal conductivity at higher temperatures may be attributed to the formation of ordered sodium nitrate layers on the nanoparticle surfaces. The increase in surface area and surface energy due to the addition of ZnO nanoparticles increased the specific heat of the nanocomposite in both the solid and liquid phases (43.5% in the liquid phase for 2 wt% ZnO-NaNO3). Thus, the addition of ZnO nanoparticles to NaNO3 increased its energy storage capacity. The addition of ZnO nanoparticles to NaNO3 did not affect the onset, peak or endset temperature during melting and freezing. Moreover, 2 wt% ZnO-NaNO3 exhibited cyclic stability even after 500 cycles and thus has potential as an energy storage medium.

Designing C9N10 Anchored Single Mo Atom as an Efficient Electrocatalyst for Nitrogen Fixation.

Electrochemical nitrogen reduction reaction (NRR) is a promising route for realizing green and sustainable ammonia synthesis under ambient conditions. However, one of the major challenges of currently available Single-atom catalysts (SACs) is poor catalytic activity and low catalytic selectivity, which is far away from the requirements of industrial applications. Herein, first-principle calculations within the density functional theory were performed to evaluate the feasibility of a single Mo atom anchored on a g-C9N10 monolayer (Mo@g-C9N10) as NRR electrocatalysts. The results demonstrated that the gas phase N2 molecule can be sufficiently activated on Mo@g-C9N10, and N2 reduction dominantly occurs on the active Mo atom via the preferred enzymatic mechanism, with a low limiting potential of -0.48 V. In addition, Mo@g-C9N10 possesses a good prohibition ability for the competitive hydrogen evolution reaction. More impressively, good electronic conductivity and high electron transport efficiency endow Mo SACs with excellent activity for electrocatalytic N2 reduction. This theoretical research not only accelerates the development of NRR electrocatalysts but also increases our insights into optimizing the catalytic performance of SACs.

AB–stacked bilayer β12–borophene as a promising anode material for alkali metal-ion batteries

As the lightest 2D material, monolayer borophene exhibits a specific charge capacity of 1860 mA h g−1 for Li-ion batteries, which is four times higher than that of graphite and is one of the highest specific charge capacities ever reported for 2D anode materials. Additionally, it showed high mechanical strength and a low diffusion barrier. However, monolayer borophene suffers from stability issues in its free-standing form, which restricts its real-life applications. Inspired by the recent experimental investigations, which proved the higher stability of bilayer borophene polymorphs (BBPs) over their monolayer counterparts, in this work, we investigated the dynamical and thermodynamical stabilities of both AA– and AB–stacked BBPs in their β12 phase using first-principles calculations. Between the two stacking patterns, we found that only the AB–stacked β12–BBP is both energetically and dynamically stable, and we further investigated its potential as a high-performance anode material for alkali metal-ion batteries. Our investigations show that AB–stacked β12–BBP exhibits good electrical conductivity before and after metal atom (Li/Na/K) adsorption onto it. Further, AB–stacked β12–BBP adsorbs the metal atoms strongly with adsorption energies ranging between −0.89 to −1.44 eV, indicating that there is a lesser possibility of forming dendrites on this anode. Similarly, it has a low diffusion energy barrier (~ 0.13–0.49 eV) for metal atoms, meeting the fast charge/discharge rate requirements. Moreover, it exhibits a reasonably low average metal-insertion voltage (0.43 to 0.65 V) and a specific charge capacity of 330–413 mA h g−1 that is comparable to graphite. All the above findings suggest that the AB–stacked bilayer β12– borophene can be a potentially favorable anode material.

Enhanced thermal conductivity of UHMWPE by coating boron nitride and polyurethane composites

The development of textile wearable electronics has increased demands and requirements for thermal management materials due to integrated and miniaturized soft equipment. In this work, the surface of ultrahigh molecular weight polyethylene (UHMWPE) fibers was first decorated by polydopamine (PDA) to improve the surface activity and construct a steady interface layer. Then the boron nitride/polyurethane coating surface modified UHMWPE composite yarns with good thermal conductivity were produced using a coaxial wet forming process. The thermally conductive composite yarns demonstrated great mechanical properties (5.09 % strain, 0.79 N/tex strength) and thermal conductivity (0.54 ± 0.02 W·mK−1) with the BN/PU weight ratio of 1. Furthermore, the resistance to failure cycles was taken place, and the composite yarns kept good thermal conductivity after multiple cycles twisting, bending, washing, cooling and heating cycles. By the coaxial wet fabrication, the thermally conductive composite yarns were constructed, offering a viable and trustworthy method for creating polymer-based thermal interface materials with high thermal conductivity.

Effect of hydroxylated boron nitride and boron nitride nanosheets on the properties of doped organosilicone rubber composites

As the electronic industry develops rapidly, the miniaturisation, integration and multifunctionality of electronic devices have resulted in a dramatic increase in power density, and the heat dispersal of electronic devices has attracted much attention. In this work, hydroxylated hexagonal boron nitride (BN-H) was obtained by hot alkali treatment, and boron nitride nanosheets (BNNS) with a thickness of about 4 nm were obtained by boric acid-assisted ball milling stripping. The effects of different types of fillers as well as filler contents on the thermally conductive and mechanical performance of organosilicon composites were also compared. Notably, when BN-H and BNNS thermally conductive fillers were added at 12 wt%, the thermally conductive coefficients of the composites were 0.4831 W·m−1·K−1 and 0.7131 W·m−1 K−1, respectively, which were 183% and 318% of higher than that for the pure silicone rubber (SR, with a thermally conductive coefficient of 0.1706 W·m−1·K−1). In addition, in respect of mechanical performance, the tensile strengths of SR/BN-H and SR/BNNS composites with a filling level of 12 wt% were 3.59 MPa and 3.89 MPa, respectively, and the storage moduli were 4501 MPa and 4583 MPa, respectively, which were improved to a certain extent compared with pure SR. The present work provides an effective way to develop organosilicone rubber composites with good thermal conductivity and mechanical properties by boric acid assisted ball milling to strip boron nitride in the field of electronics packages.

Comparison of Heat Transfer Performance of Lattice-Structured Heat Sinks

This paper presents a comparative study of the heat transfer performance of lattice-structured heat sinks. Twenty different unit cells are chosen, and heat sinks are modeled in nTop with constant unit cell size. Al 6061 alloy is chosen as the material for analysis due to its good thermal conductivity, low weight, low cost, and high strength. Steady-state thermal analysis is performed using ANSYS with constant input parameters for all samples. Heat flux and temperature distribution within the heat sinks are analyzed. From the simulation, it was found that TPMS and plate-based heat sinks outperform other types with better heat transfer.

Eutectogels: The Multifaceted Soft Ionic Materials of Tomorrow.

Eutectogels, a rising category of soft materials, have recently garnered significant attention owing to their remarkable potential in various domains. This innovative class of materials consists of a eutectic solvent immobilized in a three-dimensional network structure. The use of eco-friendly and cost-effective eutectic solvents further emphasizes the appeal of these materials in multiple applications. Eutectogels exhibit key characteristics of most eutectic solvents, including environmental friendliness, facile preparation, low vapor pressure, and good ionic conductivity. Moreover, they can be tailored to display functionalities such as self-healing capability, adhesiveness, and antibacterial properties, which are facilitated by incorporating specific combinations of the eutectic mixture constituents. This perspective article delves into the current landscape and challenges associated with eutectogels, particularly focusing on their potential applications in CO2 separation, drug delivery systems, battery technologies, biocatalysis, and food packaging. By exploring these diverse realms, we aim to shed light on the transformative capabilities of eutectogels and the opportunities they present to address pressing industrial, academic, and environmental challenges.

SnIn4S8/FeNi2P Z-scheme heterojunction hollow nanorods for photocatalytic hydrogen production

Climate change and natural disasters have stimulated the exploration of renewable energy, photocatalytic hydrogen production utilizing solar energy is considered an effective way. In this study, hollow FeNi2-MIL-88 nanorods were synthesized by the hydrothermal method, and then FeNi2P was obtained by gas phase phosphorization. Finally, SnIn4S8 was utilized to coat the surface of FeNi2P through an in-situ growth method to obtain rod-like SnIn4S8/FeNi2P. The results showed that the hydrogen production of SnIn4S8/FeNi2P reached 18083.93 μmol/g within 3 h. And SnIn4S8/FeNi2P showed good stability. The photocurrent response spectra and electrochemical impedance spectra confirmed that SnIn4S8/FeNi2P had good carrier conductivity and effectively inhibited the reorganization of photogenerated carriers. The modification of SnIn4S8 enabled the construction of a Z-scheme heterojunction between SnIn4S8 and FeNi2P. It provided more active sites and promoted the separation of photogenerated carriers, ultimately improving the hydrogen production performance of the SnIn4S8/FeNi2P photocatalyst. It would offer essential insights into the design and development of efficient MOFs-derived photocatalysts.

Experimental Verification of Inter Relation between Fowler–Nordheim and Millikan–Lauritsen Plot in Chemically Synthesized Zinc Oxide System

AbstractCold cathode emission or cold field emission (CFE) is a purely quantum mechanical phenomenon and a phenomenon of wonder. The exact science behind the observed current (I)–voltage (V) is yet to be pin pointed. For instance, a good cold emitter is very reasonably supposed to have low work function and good conductivity whereas a carbon allotropes like diamonds have just the reverse in both the cases, i.e., it is insulating in nature having very wide band gap as well as high work function yet it is considered to be an efficient field emitter. Since early of 20th century, till its middle a number of groups have suggested different equations or relations that can adequately describe the experimental CFE I–V characteristics adequately. Although they all fundamentally follow an exponential law, but so far, the relation suggests by Fowler and Nordheim (F–N) is the most accepted one. However, there is another relationship suggested by Millikan and Lauritsen (M–L) which is in spite of being reasonable not so common now a day to use. This work revisits different popular approaches for analyzing cold emission data. With this aim, the experimental CFE data obtained for chemically synthesized zinc oxide nanorods are chosen. The proper phase formation of ZnO is confirmed by XRD study whereas FESEM shows the rod like morphology. EDX confirms the proper stoichiometric ratio for the sample. After detail analysis it is confirmed that the theoretically proposed relation between F–N and M–L experimentally holds good as well and thus it would not be wrong to analyze the CFE data by simple M–L theory.