Vittayakorn, Wanwilai

Preferred name

Alternative Name

Vittayakorn, W.

Vittayakorn, Wanwilai C.

Main Affiliation

Integrated Innovative Technology

wanwilai.vi@kmitl.ac.th

Now showing 1 - 10 of 20

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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
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Pharino, Utchawadee
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Charoonsuk, Thitirat
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Pulphol, Phieraya
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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.]
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AC Conductivity and dielectric properties of lepidocrocite-type alkali titanate tunable by interlayer cation and intralayer metal
(2020-11-02)
Charoonsuk, Thitirat
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Sriphan, Saichon
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Pulphol, Phieraya
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Vittayakorn, Wanwilai
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Vittayakorn, Naratip
The lepidocrocite-type layered alkali titanate AxMyTi2-yO4 has diverse chemical compositions with variation in charge per formula unit x, the interlayer cation A+, and the intralayer metal M. Despite this multivariable nature, the composition dependence of physical properties is not well explored. We report herein the AC conductivity and the complementary dielectric properties of Cs0.7M0.35Ti1.65O4, K0.8M0.4Ti1.6O4 (M = Zn, Ni), and the mixed-interlayer ion Cs0.6K0.1Zn0.35Ti1.65O4. For Cs0.7Zn0.35Ti1.65O4, the total AC conductivity is ~7 × 10-8 to 2 × 10-6 S·cm-1 at 200-350 °C, associating with an activation energy Ea ∼865 meV. Meanwhile, the conductivity of K0.8Zn0.4Ti1.6O4 is higher by 1 order of magnitude at much lower temperature (25-150 °C) and a smaller Ea ∼250 meV. This difference originates from the compositional robustness of the cesium-containing samples, contrasting with the sintering-induced changes in the potassium analogues. For the latter, the loss of the interlayer K+ ion results in (i) generation of carriers due to charge compensation, (ii) reduction of sheet charge density and weakening of electrostatic attraction, and (iii) widening of the interlayer distance, all contributing to a lower Ea in K0.8M0.4Ti1.6O4. The angular frequency dependence of conductivity, dielectric permittivity (up to a colossal value of 109), and dielectric loss follows the universal power law. Our work demonstrates the potential of simple compositional variation for electrical properties tuning, prompting a more in-depth investigation covering a wider range of possible candidates of x, A+, and M in lepidocrocite titanate.
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Towards the preparation of organic ferroelectric composites: fabrication of a gamma-glycine-bacterial cellulose composite via cold sintering process
(2023-07-01)
Noisak, Jitrawan
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Charoonsuk, Thitirat
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Pongampai, Satana
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Pinpru, Nattapong
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Pakawanit, Phakkhananan
The cold sintering process (CSP) has emerged as a revolutionary technique for low-temperature processing of ceramics and composites, enabling high-density fabrication at low temperatures. In this study, we demonstrated the implementation of CSP in fabricating the γ-glycine (γ-G)-bacterial cellulose (BC) composite and evaluated the effect of sintering temperature and holding time on the microstructure and electrical properties. Our findings revealed that an increase in sintering temperature and holding time leads to grain growth, as the transient solvent (water) facilitates the closely-packed microstructure. Moreover, the addition of BC as a filler into the γ-G matrix leads to a composite with a 10% increase in hardness when BC was uniformly distributed in γ-G. The composite with a relative density of 97% was successfully obtained at 120 °C/24 h, preserving the γ polymorph of glycine without the unwanted transformation commonly observed with traditional sintering. We also reported the dielectric and ferroelectric properties of the γ-G-BC composite, exhibiting a remanent polarization of 0.004 μC/cm2 and a coercive field of 1.201 kV/cm. Our findings suggest that CSP is a promising approach for low-temperature processing and fabrication of ceramics, especially when incorporating structurally sensitive filler such as organic ferroelectric, to achieve high-performance composites.
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An architected silk fibroin-lignin multilayer with deep-level trapping states for high-output triboelectric nanogenerators
(2026-03-01)
Suktep, Natdanai
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Sae-tang, Chanachot
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Ukasi, Sirinya
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Pakawanit, Phakkhananan
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Supansomboon, Supitcha
Biopolymer-based triboelectric nanogenerators (B-TENGs) are promising power sources for sustainable and flexible electronics, but their performance is often limited by severe charge recombination at the triboelectric interface. To overcome this critical bottleneck, we report an architected multilayer B-TENG featuring a silk fibroin (SF)/MgAl LDH composite as the charge-generating layer and, to our knowledge, for the first time, a lignin-functionalized SF film as a dedicated charge-trapping layer. The strategic incorporation of lignin, an abundant and sustainable biopolymer, introduces deep-level electronic trapping states originating from its abundant aromatic moieties. That effectively suppresses interfacial charge recombination and prolongs charge lifetime. By optimizing the contents of MgAl LDH and lignin, the device achieves a measured open circuit output voltage ( V <inf> OC </inf>) and current density ( J <inf> SC </inf>) of 96 V and 6.56 μA/cm3, with a maximum output power ( P <inf> max </inf>) of 205 μW, corresponding to a power density of 22.7 μW/cm2. We also propose a mechanistic linking of deep-level traps to prolonged charge lifetime and increased net transferable charge. The interface-engineering strategy demonstrated here paves the way for developing high-performance and sustainable biopolymer-based TENGs and motion sensors.
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Sonochemical synthesis of monodispersed perovskite barium zirconate (BaZrO3) by using an ethanol-water mixed solvent
(2015-07-01)
Charoonsuk, Thitirat
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Vittayakorn, Wanwilai
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Vittayakorn, Naratip
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Seeharaj, Panpailin
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Maensiri, Santi
Perovskite barium zirconate (BaZrO<inf>3</inf>) was synthesized successfully in an ethanol-water mixed solvent under ultrasonic irradiation. Four compositions, including 0%, 30%, 50%, and 70% by volume of ethanol in ethanol/water mixed solvent, were used. The effect of ethanol content and irradiation time on the phase formation and morphology of product particles was studied and discussed. As a result, a pure perovskite BaZrO<inf>3</inf> phase was formed completely at a short irradiation time of about 15 min in 70% by volume of ethanol without the calcination process. The average particles size decreases and particle size distribution becomes narrower by increasing the percentage of ethanol volume. On the other hand, the monodispersibility of BaZrO<inf>3</inf> particles was improved significantly through ultrasonic irradiation.
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The role of γ-C2H5NO2 as a new transient liquid phase in cold sintering process of BaTiO3 composites
(2024-07-01)
Noisak, Jitrawan
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Ieamviteevanich, Pimchanok
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Charoonsuk, Thitirat
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Pakawanit, Phakkhananan
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Pinpru, Nattapong
Dielectric materials, such as barium titanate (BT)-based materials, have excellent dielectric properties but require high temperatures (above 1300 °C) for ceramic fabrication, leading to high costs and energy loss. The cold sintering process (CSP) offers a solution to these issues and is gaining worldwide attention as an innovative fabrication route. In this work, we proposed an alternative organic ferroelectric phase, gamma-glycine (γ-GC), which acts as a transient liquid phase to fabricate high-density composites with barium titanate (BT) at low temperatures through CSP. Our findings show that the density of 15γ-GC/85BT reached 96.7%±1.6% when it was sintered at 120 °C for 6 h under 10 MPa uniaxial pressure. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) mappings of the composite suggested that γ-GC completely underwent the precipitation–dissolution process and, therefore, filled between BT particles. Moreover, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the preservation of γ-GC without undesired phase transformation. In addition, the ferroelectric and dielectric properties of γ-GC/BT composites have been reported. The high dielectric constant (ε<inf>r</inf>) was 3600, and the low dielectric loss (tanδ) was 1.20 at 200 °C and 100 kHz for the 15γ-GC/85BT composite. The hysteresis loop showed a remanent polarization (P<inf>r</inf>) of 0.55 µC·cm-2 and a coercive field (E<inf>c</inf>) of 7.25 kV·cm-1. Our findings reaffirmed that an organic ferroelectric material (γ-GC) can act as a transient liquid phase in a CSP that can successfully and sustainably fabricate γ-GC/BT composites at low temperatures while delivering outstandingly high performance.
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Water Repellent Modified Polyester Fabric Based Triboelectric Nanogenerator for Harvesting Human Mechanical Energies
(2021-01-01)
Pharino, Utchawadee
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Ausaman, Kanyamon
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Phonimdang, Kunyapak
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Pongampai, Satana
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Vittayakorn, Wanwilai
Wearable triboelectric nanogenerators (TENGs) for converting human mechanical energies into electricity are being investigated widely, because of their potentially diverse applications that come from wearable power supplied to multifunctional self-powered sensing. However, external influences, such as water or high humidity, seriously degrade the electrical output of TENGs. Therefore, a simple method was implemented for fabricating a water repellent fabric-based TENG for harvesting human mechanical energies. Polytetrafluoroethylene (PTFE) or SiO<inf>2</inf> modified by trichloro(octadecyl)silane (OTS) were sprayed onto a polyester (PET) fabric surface to increase hydrophobicity. The PTFE and SiO<inf>2</inf>/OTS coated polyester fabrics exhibited excellent water repellency with a high-water contact angle of ∼144° and ∼153°, respectively. The surface morphology of the coated fabrics showed roughness with a granular structure, which was responsible for air entrapment that prevented water from penetrating the fabric. Furthermore, electrical output of conventional PET fabric-based TENG was found to improve with the deposition of PTFE particles on the fabric surface. By pairing the PTFE coated fabric with aluminum (Al) tape, in order to fabricate TENG, the device generated a maximum voltage of 10.2 V and short-circuit current of 0.20 µA, with a power output of 0.23 (Formula presented.) W/cm2, which is 14 times greater than that of SiO<inf>2</inf>/OTS coated fabric-based TENG. The process for achieving water repellent fabric is simple, and the coating materials are available. Thus, a water repellent fabric-based TENG is promising for large-scale production of wearable harvesters from power supplied to multifunctional self-powered sensing.
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Simple enhanced charge density of chitosan film by the embedded ion method for the flexible triboelectric nanogenerator
(2022-12-01)
Charoonsuk, Thitirat
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Supansomboon, Supitcha
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Pakawanit, Phakkhananan
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Vittayakorn, Wanwilai
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Pongampai, Satana
This research proposed a simple ionic embedded method to improve electrical output performance by adding surface charges of cationic chitosan (CS) biopolymer for compatible utilization of the triboelectric nanogenerator (TENG). By simply embedding cationic salts, the TENG performance was enhanced by over four times more than that with pristine CS. Moreover, by modifying roughness on the film surface, the optimized condition of R-CS/3 %CaCl<inf>2</inf> reached the highest V<inf>OC</inf> and I<inf>SC</inf> of ~149 V and ~15 μA, respectively, thus exceeding the output from pristine R-CS TENG by four- and three times of ⁓38 V and ⁓5.1 μA. The maximum power output of 400 μW/cm2 can be observed at the 10 MΩ external load resistance. Finally, by integrating an automatic self-charge pumping (ASCP) module, the ASCP/CS-TENG provided highly efficient V<inf>OC</inf> and I<inf>SC</inf> output power by over 1.3 times more than the R-CS/3 %CaCl<inf>2</inf> TENG and could light up 72 light emitting diodes (LEDs) easily.
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High Performance Flexible Tribo/Piezoelectric Nanogenerators based on BaTiO3/Chitosan Composites
(2021-01-01)
Pongampai, Satana
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Charoonsuk, Thitirat
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Pinpru, Nattapong
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Muanghlua, Rangson
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Vittayakorn, Wanwilai
Natural biopolymer materials have been of interest in wearable energy harvester technology, especially in biocompatible triboelectric nanogenerators (BTENGs), due to their biodegradable, biocompatible, nontoxic and excellent antibacterial properties. Nevertheless, obstacles concerning economical and biocompatible utilization of triboelectric nanogenerators (TENGs) continue to prevail. The natural biopolymer, chitosan (CS), is composed of a long biopolymer chain of N-acetyl glucosamine. It enables exciting opportunities for low-cost, biodegradable triboelectric nanogenerator (TENG) applications. However, the electrical output performance of CS based on TENGs is low when compared with devices constructed from synthetic polymers. Hence, to enhance electrical output performance, BaTiO<inf>3</inf> nano-powders (BT-NPs) were embedded into the CS as dielectric material, in order to improve electrical properties by increasing the dielectric constant of the composite film. A flexible hybrid piezo/triboelectric nanogenerator, designed by BT-NPs embedded into CS (BT-NPs/CS) composite film, was constructed successfully. The effects of the BaTiO<inf>3</inf> nano-powder (BT-NP) content on the output performance were explored systematically. The device with 5 wt% BT-NPs in CS, and a 160-μm-thick film, exhibited maximum open-circuit voltage (V<inf>OC</inf>) and transferred short-circuit current (I<inf>SC</inf>) of 110.8 V and 10 µA, respectively, as well as maximum power output of 431.8 µW. Practical and application demonstrations also were investigated, namely charged capacitors for storing energy, testing voltage stability and driving commercial LEDs. This work exhibited high electrical performance enhancement of BT-NPs/CS nanocomposite film, which demonstrated better material modification.
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FABRICATION OF BA5NB4O15 CERAMICS BY FLUX-ASSISTED ULTRA-LOW SINTERING TEMPERATURE TECHNIQUE
(2025-01-01)
Pulphol, Phieraya
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Teandam, Apichayaporn
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Charoonsuk, Thitirat
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Vittayakorn, Wanwilai
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Maluangnont, Tosapol
Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> ceramic is a promising dielectric material for microwave frequencies. One of the factors that affects its dielectric properties is density, which can be controlled by fabrication processes such as sintering. Normally, conventional sintering requires high sintering temperature (T?> 1,200ºC) to produce grain coarsening and pore reduction which consumes high energy. However, there has been growing interest in low-temperature ceramic processing due to its potential to revolutionize the way ceramic materials are manufactured. Cold sintering is a new sintering technique that can be used to fabricate dense ceramics below 300°C. It can be applied to a variety of compounds, and the densification process is driven by the dissolution-precipitation mechanism, with the aid of a congruent solvent, pressure, and temperature. Herein, Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> ceramics are prepared by cold sintering technique using hydrated barium hydroxide (Ba(OH)<inf>2</inf>-8H<inf>2</inf>O) as a flux to reduce sintering temperature and introduce densification process. The effects of processing parameters, including sintering temperature, dwelling time, pressure, and flux concentration, on the density and dielectric properties of sintered samples were investigated. Phase formation and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and an LCR meter. Under the sintering conditions T = 150°C, pressure = 7,000 kPa, and t = 60 min, the obtained Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> ceramic exhibited a relative density of ˜80% which closes to the ceramics obtained from conventional sintering. These results suggest that sintering temperature has little influence on sample density, while applied pressure is the dominant factor in improving density. The mechanism of flux-assisted cold sintering and dielectric properties are also discussed.

Vittayakorn, Wanwilai

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