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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
    ;
    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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    ;
    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
    ;
    Charoonsuk, Thitirat
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    Pinpru, Nattapong
    ;
    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/cm<sup>2</sup> 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/cm<sup>3</sup>, with a maximum output power ( P <inf> max </inf>) of 205 μW, corresponding to a power density of 22.7 μW/cm<sup>2</sup>. 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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    Recycling of Broken Waste Glass as Polyethylene Nanofiller for Electrical Insulating System
    (2022-01-01) ;
    Khunna, D.
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    Buaphuen, P.
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    Makcharoen, W.
    This work focuses on the preparation of a high-quality glass powder from the broken windowpane. The expected glass powder must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 0.3 to 7 µm, and the 270 min-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder is rich in silica which contained about 70.47% of SiO<inf>2</inf>. After that, the various ratios of the glass powder/HDPE composites were formed by using the traditional casting method. The physical and electrical properties were investigated for all composites. The results showed that after adding glass powder into the HDPE matrix, the ε<inf>r</inf> value significantly drops due to the inorganic filler suppressed polarization within the systems. For the resistivity, the ρ value significantly increases after adding glass powder to the HDPE matrix for all compositions because this filler promotes the hinder of electric current flow. Finally, it can conclude that the waste glass powder can use as a filler in the HDPE-based composite as better as the commercial SiO<inf>2</inf> powder for the electrical insulting application.
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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<sup>-2</sup> and a coercive field (E<inf>c</inf>) of 7.25 kV·cm<sup>-1</sup>. 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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    BaTiO3/Epoxy Resin Nanocomposites as Flexible Energy Storage Devices
    (2023-01-01) ;
    Tepsansern, Piyapat
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    Kriangkraikul, Worachet
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    In this work, nanocomposites between the epoxy resin and barium titanate (BT) were prepared in order to use as flexible energy storage devices. The epoxy resin and BT phase were homogeneously mixed and cast into a disk shape. Phase formation and chemical properties of these nanocomposites were identified via XRD and FTIR methods, respectively. Frequency dependence of dielectric properties for all samples was measured by LCR meter. The polarization hysteresis loops were also investigated in order to calculate the energy density of materials. From the results, it was found that the dielectric constant and loss of these nanocomposites are independent of frequency and the ε<inf>r</inf> and tanδ values tend to increase with increasing BT amount. Moreover, after adding 50% of BT into the system, the energy density of nanocomposites is increased by five times compared with the pure epoxy resin while the energy loss density sharply decreases. The dielectric properties and the energy density of BT/epoxy resin nanocomposites change with BT content and strongly depend on porosity and the distribution of BT nanoparticles.
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    A highly sensitive disease pre-screening approach for glycosuria: Triboelectric sensing at the liquid-solid interface
    (2025-03-15)
    Pharino, Utchawadee
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    Chaithaweep, Kanokwan
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    Chanlek, Narong
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    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.
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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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    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/cm<sup>2</sup>, 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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    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/cm<sup>2</sup> 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.