KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 15

Some of the metrics are blocked by your
consent settings
Kinetic analysis of liquid–solid contact electrification: Using adsorption models as mechanistic probes for hybrid EDL behavior
(2026-08-01)
Chaithaweep, Kanokwan
;
Pharino, Utchawadee
;
Pongampai, Satana
;
Sriphan, Saichon
;
Charoonsuk, Thitirat
Liquid–solid interfaces are central to technologies ranging from energy storage to triboelectric nanogenerators (TENGs). Whereas classical electric double layer (EDL) theory describes these interfaces mainly in terms of electrostatic ion adsorption, hybrid EDL concepts suggest that interfacial electron transfer may also contribute importantly to charge generation. However, the hybrid EDL model has so far been discussed primarily at a qualitative level or through complex theoretical and computational treatments, and a simple, experimentally accessible macroscopic kinetic handle that can discriminate, in operando, between adsorption‑dominated and ET‑influenced regimes remains lacking. By analyzing high-resolution charging dynamics over systematically varied H₂SO₄ and HNO₃ concentrations, a clear concentration-dependent kinetic transition is identified. At low ionic strengths, the charging process is described more effectively by pseudo-second-order (PSO) kinetics, consistent with a reaction-influenced interfacial step, whereas at higher concentrations the system becomes pseudo-first-order (PFO) dominated, consistent with transport- and ion-screening-controlled behavior. Although previous studies have provided compelling theoretical and spectroscopic evidence that interfacial electron transfer contributes to liquid–solid contact electrification in TENGs, these mechanisms have rarely been examined through such simple macroscopic kinetic formalisms. In this work, classical adsorption kinetic models are used as operational probes for distinguishing electron-transfer-influenced regimes from ion-transport-dominated regimes at PTFE/liquid interfaces. The PSO-to-PFO crossover reported here is interpreted within the hybrid EDL framework as a kinetic marker of a transition from an electron-transfer-influenced charging regime at low concentration to an ion-transport- and screening-dominated regime at high concentration, thereby demonstrating how adsorption kinetics can serve as a practical diagnostic language for liquid–solid triboelectric systems.
Some of the metrics are blocked by your
consent settings
High-Performance Droplet-Based Triboelectric Nanogenerators: A Comparison of Device Configuration and Operating Parameters
(2025-05-06)
Chaithaweep, Kanokwan
;
Pharino, Utchawadee
;
Pongampai, Satana
;
Hajra, Sugato
;
Kim, Hoe Joon
Droplet-based electricity generators (DEGs) harness liquid-solid electrification to convert water droplets impacts into electrical energy. This study systematically examines how droplet height, droplet volume, flow rate, and substrate tilt angle influence DEG performance using polytetrafluoroethylene (PTFE) as a triboelectric layer and deionized water. Three electrode designs (double, top, bottom) are evaluated, revealing that the double-electrode configuration delivers the highest output. This enhanced performance arises from synergistic droplet motion, electrical double-layer formation, and charge discharge, as validated by an equivalent circuit model. By varying droplet heights from 1–20 cm, volumes of 7.7–50 µL, flow rates of 50–300 drops/min, and tilt angles of 0–90°, an optimized setup yields −70 V and 22 mA, translating to a power density of 0.28 µW cm<sup>−2</sup>. High-speed imaging correlates these outputs with droplet impact dynamics and the resulting charge transfer. Additionally, the optimized DEG can power small electronic devices, charge capacitors, and monitor artificial acid rain in real-time, displaying distinct electrical signals compared to typical rainwater. These findings underscore the potential of DEGs as renewable energy harvesters and smart environmental sensors, paving the way for advanced on-demand power generation in diverse settings.
Some of the metrics are blocked by your
consent settings
A highly sensitive disease pre-screening approach for glycosuria: Triboelectric sensing at the liquid-solid interface
(2025-03-15)
Pharino, Utchawadee
;
Chaithaweep, Kanokwan
;
Pongampai, Satana
;
Chanlek, Narong
;
Kothan, Suchart
Prescreening and disease detection offer significant benefits in the prevention of serious illnesses. Traditional screening methods for disease identification have been complex and expensive, often requiring invasive procedures, which can be both harmful and uncomfortable. To address these limitations, various non-invasive screening technologies have been developed. Among recent innovations, the liquid–solid interface concept has emerged as a promising avenue for nanogenerator applications, enabling the harvesting and sensing of liquid energy and substances. In this study, we introduce a liquid–solid interface triboelectric sensor (LS-TES) for non-invasive disease screening and sensing. The LS-TES, utilizing a double-electrode configuration, delivers an immediate electrical response upon droplet contact with the solid surface and top electrode. In the case of urine glucose monitoring, our findings demonstrate a significant reduction in electrical signals with increasing concentrations of glucose, as glucose molecules hinder electron transfer from water to the solid surface, thereby disrupting the formation of the electrical double layer at the liquid–solid interface. The sensor exhibits excellent glucose sensing performance within a concentration range of 0.2 mM to 14 mM, with a detection limit of 0.25 mM and a rapid response time of 5–10 s. The LS-TES is cost-effective, highly stable, and reusable, maintaining consistent electrical responses across ten cycles of alternating droplet measurements. This work presents a preclinical assessment approach, specifically for urine glucose monitoring, utilizing an innovative sensor based on the liquid–solid interface. The proposed concept has the potential to serve as an individual indicator for early medical symptom detection, offering relief to a large number of patients.
Some of the metrics are blocked by your
consent settings
Frictional heat-assisted performance enhancement in dynamic Schottky contact of Al/Ag2Se-based tribovoltaic nanogenerator
(2025-01-01)
Worathat, Supakarn
;
Pharino, Utchawadee
;
Pakawanit, Phakkhananan
;
Rattanachata, Arunothai
;
Muanghlua, Rangson
The tribovoltaic nanogenerator (TVNG) has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge generation. Besides the outstanding characteristics, the tribovoltaic effect can also well be coupled with another effect to further boost the output performance. In this work, we proposed firstly a frictional heat-assisted performance enhancement in dynamic Schottky contact from the rubbing between n-type silver selenide (Ag<inf>2</inf>Se) and aluminum. The chemical composition and physical characteristics of the Ag<inf>2</inf>Se ceramic were analyzed using X-ray diffraction, scanning electron microscopy, and Synchrotron X-ray tomography techniques. UV–Vis spectroscopy and UPS were also utilized in order to validate the semiconducting property of the n-type Ag<inf>2</inf>Se ceramic. Moreover, the presence of the Schottky junction was demonstrated through the analysis of the current-bias voltage characteristic curve of the Ag<inf>2</inf>Se/aluminum (Al) contact under varying stress and temperature conditions. The built-in electric field plays a crucial part in the tribovoltaic effect by efficiently transferring the excited carriers to an external load through sliding contact between Ag<inf>2</inf>Se and Al. Demonstrating the synergy between tribovoltaic and thermoelectric effects becomes achievable through the excellent thermoelectric property of Ag<inf>2</inf>Se. Herein, the proposed TVNG generated a peak output voltage and current of around 0.7 V and 24.8 nA, respectively, achieving a maximum output power of 12.6 nW at a load resistance of 10 kΩ. The influence of frictional heat on the output performance of the proposed TVNG was well demonstrated by the thermal-induced voltage and enhanced electrical output from continuous sliding. The concepts given in this study establish the basis for the progress of effective energy collection employing semiconducting materials and the advancement of flexible harvesting and sensing device development in the future.
Some of the metrics are blocked by your
consent settings
Exploring liquid-solid interface based triboelectrification, structures, and applications
(2024-12-01)
Kaja, Kushal Ruthvik
;
Hajra, Sugato
;
Panda, Swati
;
Belal, Mohamed A.
;
Pharino, Utchawadee
In recent years, there has been a quest to accelerate the search for efficient and sustainable energy harvesting technologies due to challenges from fossil fuel depletion and environmental concerns. There is also a continous demand for autonomous sensing in our growing connected world. The liquid-solid triboelectric nanogenerator (L-S TENG) has emerged as a viable alternative, notably for generating mechanical energy from water. Despite extensive study into liquid-solid contact electrification techniques, a significant need remains to improve energy harvesting efficiency in L-S TENG systems. This comprehensive analysis delves into recent advances in energy harvesting from water, with a particular emphasis on understanding the interaction dynamics between liquid-solid interfaces when using triboelectric nanogenerators for energy conversion. This review summarizes recent developments in the structural design and applications of liquid-solid triboelectrification, focusing on improving TENG output performance. In addition, new insights are provided on the potential impact and future technical hurdles facing L-S TENG technologies. By offering new insights into current knowledge and future research directions, this review aims to guide progress in the field of L-S TENG energy harvesting.
Some of the metrics are blocked by your
consent settings
Equivalent circuit model and simulation for dynamic sliding droplet-based triboelectric nanogenerators
(2024-11-01)
Sriphan, Saichon
;
Pharino, Utchawadee
;
Chaithaweep, Kanokwan
;
Vittayakorn, Naratip
Recently, there has been an increase of attention to employing liquid-solid contact to harvest or sense energy from water flow. Water's considerable deformability, however, makes it challenging to investigate how water moves dynamically in relation to a water-based triboelectric nanogenerator's (TENG) output characteristic. There are a few studies examining the fundamental mechanism of a droplet-based energy generator (DEG). In addition, such an electrical model has been established based on the consideration of instantaneous output at a specific period in a saturated state. Here, we first propose the circuit model and governing equations for simulating the double-electrode DEG's electrical output, comprehensively covering the L-S contact's dynamic process. Four essential stages of charge generation of the DEG are considered in unsaturated and saturated stages. The proposed model is verified systematically with the experimental data. The relationship between structural parameters and output performance of the DEG, such as internal capacitance, residual charge, dielectric constant, droplet spreading size, and dielectric thickness, has emerged. In summary, our model effectively establishes theoretical guidance, which paves the way for high-performance supply and sensor applications based on the L-S interface.
Some of the metrics are blocked by your
consent settings
Highly Flexible Tribovoltaic Nanogenerator Based-on P-N Junction Interface: Comparative Study on Output Dependency Dominated by Photovoltaic Effect in Freestanding-Mode
(2023-10-18)
Sriphan, Saichon
;
Worathat, Supakarn
;
Pharino, Utchawadee
;
Chanlek, Narong
;
Pakawanit, Phakkhananan
The emergence of tribovoltaic nanogenerators (TVNGs) paves the way for developing a new kind of semiconductor-based energy harvester that overcomes the restriction of low output current in a conventional approach. The traditional TVNG generally depends on the frictional pair between two rigid semiconductors (or metal-semiconductor), limiting the practicability of flexible and portable electronics. Recent developments require the fundamental understanding of charge generation in diverse operating modes and structures. Here, a flexible TVNG based on the p-Cu<inf>2</inf>O/n-g-C<inf>3</inf>N<inf>4</inf> interface is presented. Operating in a freestanding mode, the proposed TVNG can generate a stable signal in any optical conditions including UV illumination, dark, and ambient. Under UV illumination, the electrical outputs of the TVNG reach 0.43 V and 2.1 µA cm<sup>−2</sup>, which are significantly larger than those obtained from dark and ambient conditions. The results demonstrate the coupling effect of three phenomena: tribovoltaic, photovoltaic, and triboelectric effects, and the unique mechanism to the observed signal is proposed. Additionally, the TVNG shows the practical feasibility of energy harvesting with capacitor charging and charge-boosting circuits. This study showcases the unique concept with potential for developing a novel flexible nanogenerator in many aspects, including material, structure, and fundamental mechanism.
Some of the metrics are blocked by your
consent settings
Tailoring charge affinity, dielectric property, and band gap of bacterial cellulose paper by multifunctional Ti2NbO7 nanosheets for improving triboelectric nanogenerator performance
(2023-02-01)
Sriphan, Saichon
;
Pharino, Utchawadee
;
Charoonsuk, Thitirat
;
Pulphol, Phieraya
;
Pakawanit, Phakkhananan
Transparent, flexible, and high-performance triboelectric nanogenerator (TENG) from nature-derived materials are required for sustainable society development. However, low triboelectricity from natural material is generally observed. Tunable electronic band diagram (EBD) through facile manipulation is one of the efficient methods to promote the TENG output, requiring fundamental, in depth understanding. Herein, we employed the high quality, single crystal-like Ti<inf>2</inf>NbO<inf>7</inf> nanosheets (NSs) with dual dielectric and semiconducting properties as filler for bacterial cellulose (BC)-based TENG. Several techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet—visible (UV—vis) absorption, energy dispersive X-ray spectroscopy (EDS), and synchrotron radiation X-ray tomographic microscopy (SRXTM) were applied to characterize the long-range structure, microstructure, optical properties, elemental composition, and three-dimensional (3D) distribution of components in the composites. The semi-transparent and flexible 5 vol.% Ti<inf>2</inf>NbO<inf>7</inf> NSs/BC preserved the integrity of cellulose, contained well-dispersed nanosheets, reduced optical band gap (4.20 vs. 5.75 eV for BC), and increased surface roughness. The dielectric permittivity and conductivity increased with nanosheets content. Adding negatively-charged Ti<inf>2</inf>NbO<inf>7</inf> NSs could regulate the charge affinity of BC composite via shifting of Fermi energy over that of Al. It is found that adding 5 vol.% NSs into the BC film improved electrical outputs (~ 36 V and ~ 8.8 µA), which are 2–4 times higher than that of pure BC, even when paired with Al which lies adjacent in triboelectric series. Our work demonstrated the method to enhance BC-based TENG performance through EBD regulation using multifunctional Ti<inf>2</inf>NbO<inf>7</inf> NSs. [Figure not available: see fulltext.]
Some of the metrics are blocked by your
consent settings
Simple Method for Enhancing Performance of the Bacterial Cellulose-Based Triboelectric Nanogenerator by Adding Conductive Interlayer
(2023-01-01)
Sriphan, Saichon
;
Pharino, Utchawadee
;
Pakawanit, Phakkhananan
;
Bongkarn, Theerachai
;
Vittayakorn, Wanwilai
Surface charge density is a key factor that greatly enhances the performance of a natural-based triboelectric nanogenerator (TENG), which is essential for future sustainable sensing and harvesting devices. This work introduced a conductive interlayer between a main frictional layer and electrode. This approach can suppress the charge recombination rate and improve the amount of charges produced during the triboelectrification process. Bacterial cellulose (BC) film was selected as a main frictional layer for the TENG. A conductive nanomaterial, i.e. silver flake, was incorporated into the BC film as an intermediate layer for enhancing TENG performance. As firstly reported, the maximum electrical outputs for the multi-layer BC structure could be found when using silver flake/BC composite (ratio 1:5) as an intermediate layer, which has 122 V and 8.2 µA of output voltage and current, respectively. This is higher than the output voltage and current of a single layer BC TENG by approximately 3 and 8 times, respectively. The maximum output power of ∼440 µW is achieved by connecting with a load resistor of ∼10 MΩ. This demonstrates an efficient strategy for designing a high performance energy harvester by adding an intermediate layer for the target of practical purposes in sustainable systems.
Some of the metrics are blocked by your
consent settings
Bacterial Cellulose/Titanate Nanotubes Composite Kirigami for Flexible and Stretchable Motion Sensor
(2023-01-01)
Chaithaweep, Kanokwan
;
Boontanoom, Thitiworada
;
Onsup, Chutimon
;
Pharino, Utchawadee
;
Pongampai, Satana
A composite of bacterial cellulose and titanate nanotubes (BC/TNT) was prepared for use as a stretchable motion sensor in smart and wearable electronics. The composite was characterized using various techniques such as UV-VIS-NIR spectroscopy, SEM, XRD, IR spectroscopy, and thermogravimetric analysis. It was found that the dielectric constant of BC/TNT was up to 2.6 times that of BC with similar loss tangent, indicating improved charge storage. The composite was also constructed into a Kirigami pattern for improved stretchability. With a tensile strain of 0.4%, the change in resistance relative to the original resistance (ΔR/R <inf>0</inf>) was found to be 5.7% and 6.9% for BC and BC/TNT, respectively, demonstrating improved sensing performance.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results