Sukkha, Usa

Preferred name

Sukkha, Usa

Main Affiliation

KMITL Prince of Chumphon Campus

usa.suk@kmitl.ac.th

Now showing 1 - 5 of 5

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The Y3+ Donor-Doped CCTO (Ca0.95Y0.05Cu3Ti4O12) Dielectric Fillers for Electrical Output Enhancement of Flexible Triboelectric Nanogenerator
(2026-06-03)
Saichompoo, Kittipan
;
Rattanawongwiboon, Thitirat
;
Kingkam, Wilasinee
;
Pakawanit, Phakkhananan
;
Sukkha, Usa
The escalating wearable electronic devices with their flexible energy sources demand has rendered the imperative scientific challenge on the development of materials for the flexible triboelectric nanogenerators (F-TENG), one of advanced energy harvesting systems. Dielectric material optimization, the Y3+ donor-doped calcium copper titanate based on exactly stoichiometric Ca<inf>0.95</inf>Y<inf>0.05</inf>Cu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTYO), serves as a critical pathway in this work for achieving enhanced F-TENG via compositing with the polydimethylsiloxane (PDMS) polymer. The enhancement of electrical output has garnered substantial interest owing to its increased relative permittivity ((Formula presented.)). The influence of the loaded CCTYO amounts on structure, morphologies, dielectric properties, and electrical output, including open-circuit voltage (V<inf>OC</inf>), short-circuit current (I<inf>SC</inf>) and power density for PDMS/CCTYO composites is investigated. As compared with loading undoped CCTO, the additional Y3+ can improve higher F-TENG output by increasing the (Formula presented.) along with maintaining the loss tangent (tan δ < 0.02) at optimized condition. The appropriate amounts of CCTYO 0.75 wt% make the PDMS/CCTYO F-TENG to achieve V<inf>OC</inf> of ∼76.4 V (8.5 V/cm2) and I<inf>SC</inf> of ∼130.0 μA (14.4 μA/cm2), which were higher than pristine PDMS for 2.7 and 4.3 times. The power density of 53 µW/cm2 is 8.9 times higher than that of 6.3 µW/cm2 from the pristine PDMS. This study also provides a COMSOL multiphysics simulation, bridging laboratory experiments, for quantifying the triboelectric capability of dielectric materials.
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Effect of thermal annealing on the structure of LiCoO2 powders prepared by co-precipitation method
(2021-12-01)
Khejonrak, Awadol
;
Chanlek, Narong
;
Sukkha, Usa
;
Triamnak, Narit
;
Chirawatkul, Prae
Lithium cobalt oxide (LiCoO<inf>2</inf>) powder was prepared by co-precipitation method and annealed at different temperatures of between 300 and 700 °C. The effect of annealing temperature and effect washing process with deionized water on the crystal structures of the prepared LiCoO<inf>2</inf> powders were thoroughly studied by Synchrotron powder X-Ray Diffraction (Syn-XRD), X-ray Absorption Spectroscopy (XAS), Dispersive Raman Microscopy (Raman) techniques. The change in chemical composition as a function of annealing temperature was also investigated by X-ray Photoelectron Spectroscopy (XPS) technique. The crystal structural results identified the phase evolution of the prepared LiCoO<inf>2</inf> powders upon heat treatment. The formation of HT-LiCoO<inf>2</inf> phase was observed at annealing temperature as low as 300 °C.
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Process-structure-property relationships in low-temperature microwave dielectric ceramics: from glass-assisted sintering to cold sintering for 5G/6G devices
(2026-12-01)
Pulphol, Phieraya
;
Tang, Ying
;
Fang, Liang
;
Vittayakorn, Wanwilai
;
Sukkha, Usa
With the rapid advancement of wireless communication from 5G to 6G, a pressing need has emerged for microwave dielectric ceramics with excellent performance at reduced processing temperatures, compatible with low-temperature co-fired ceramic technology. This review traces historical milestones and highlights modern design strategies for achieving optimum dielectric constant, ultra-low dielectric loss, and near-zero temperature coefficient of resonant frequency. Special emphasis is placed on recent advances in low-temperature densification routes, including sintering aids, intrinsically low-sintering-temperature ceramic families, and novel techniques like the cold sintering process. This review provides a critical analysis of the performance trade-offs inherent to each strategy, addressing the persistent challenges in achieving ultra-low loss. Furthermore, we highlight the paradigm shift toward a holistic, multifunctional design imperative for 6G systems. Finally, the transformative potential of cross-disciplinary approaches, particularly AI-assisted discovery, and computational modeling, is discussed as a key enabler for accelerating the design of next-generation, high-performance, and sustainable LTCC-compatible materials.
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Cold sintering-assisted low temperature fabrication of dense Ba5Nb4O15 ceramics
(2026-06-08)
Sukkha, Usa
;
Teandam, Apichayaporn
;
Pakawanit, Phakkhananan
;
Kamonpha, Phitsamai
;
Vittayakorn, Wanwilai
This study presents a novel approach for fabricating Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> (BNO) ceramics at low sintering temperatures via the cold sintering process (CSP), using Ba(OH)<inf>2</inf>·8H<inf>2</inf>O (BOH) as a transient liquid phase. CSP was performed under an external pressure of 10MPa with a sintering temperature range of 150°C to 300°C. Optimally, BNO-BOH ceramics achieved a relative density of 93.7 ± 0.43 when sintered at 250°C for 1h. Scanning electron microscopy (SEM) suggested that particle densification occurred via a dissolution-precipitation process, which filled pores and formed necks between particles. The study demonstrates that the residual liquid content is crucial for ceramic densification. Annealing the as-cold sintered BNO-BOH ceramics at 1000°C for 1h successfully eliminates the BaCO<inf>3</inf> secondary phase. Furthermore, dielectric properties of annealed ceramics were also characterized at room temperature from frequency range of 20Hz to 2MHz. The dielectric permittivity is reported to be 39.2 and 0.01 for tanδ at 1.8MHz. The cold sintering process provides an effective strategy to reduce the sintering temperature while achieving high relative density. This method offers a promising alternative for the fabrication of advanced ceramics.
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Thermally induced phase transition and dielectric relaxation in lead-free BaTi0.94Sn0.06O3 Ceramics: Insights from in-situ XRD and XAS
(2025-11-01)
Sukkha, Usa
;
Chanlek, Narong
;
Kidkhunthod, Pinit
;
Kolodiazhnyi, Taras
;
Vittayakorn, Wanwilai
Lead-free BaTi<inf>0.94</inf>Sn<inf>0.06</inf>O<inf>3</inf> (BTS) ceramics were synthesized using the conventional solid-state reaction method to investigate thermally induced phase transitions and dielectric relaxation phenomena. A combination of in-situ X-ray Diffraction (XRD) and in-situ Synchrotron X-ray Absorption Spectroscopy (XAS) was employed to examine phase transitions across the temperature range of 200–400 K. The results reveal sequential phase transitions: rhombohedral-orthorhombic (R + O) at 200 K, orthorhombic (O) at 250–300 K, tetragonal (T) at 325–359 K, and tetragonal-cubic (T + C) at 373–400 K. Dielectric measurements highlight an anomalous relaxation behavior at 70–160 K, attributed to domain wall freezing. This phenomenon follows Vogel-Fulcher behavior, with an activation energy of 14 meV, a freezing temperature of 82 K, and an attempt frequency of 4.7 × 106 Hz. X-ray Photoelectron Spectroscopy (XPS) analysis reveals oxygen deficiency on the surface of the BTS ceramic, resulting in the coexistence of Ti3+/Ti4+ and Sn2+/Sn4+ oxidation states. These defects significantly influence the dielectric and phase transition properties. This study provides comprehensive insights into the interplay between local structural changes and phase transition mechanisms in BTS ceramics. By employing a multi-technique approach, it advances the understanding of dielectric and ferroelectric behaviors, positioning BTS ceramics as promising candidates for lead-free dielectric and ferroelectric device applications.

Sukkha, Usa

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