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Author: search.filters.author.Bongkarn, TheerachaiSubject: search.filters.subject.Energy harvesting

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    Piezoelectric composite films for real-time foot strike detection and energy generation
    (2025-12-16)
    Panpho, Phakakorn
    ;
    Charoonsuk, Thitirat
    ;
    Vittayakorn, Naratip
    ;
    Charoenthai, Nipaphat
    ;
    Bongkarn, Theerachai
    Energy harvesting technology integrated into running shoes enables the conversion of mechanical energy from foot strikes into electrical signals for real-time monitoring. This approach enhances running efficiency, reduces injury risk, and eliminates the need for external power sources. In this study, composite films combining lead-free piezoelectric ceramics (KNNS-BNZ-xBF) with PDMS were developed for efficient energy harvesting and accurate detection of foot-strike patterns. XRD analysis revealed a broad R–O–T phase coexistence zone (0 ≤ x ≤ 0.006) and a transition to an R–T phase boundary for x > 0.006, with reduced grain size as xBF increased. The sample with xBF = 0.006 mol.% showed optimal electrical properties and was selected for composite film fabrication. Electrical output increased with ceramic loading, reaching maximum open-circuit voltage (V<inf>OC</inf>) and short-circuit current (I<inf>SC</inf>) at 18 wt% KBB due to enhanced piezoelectric response and uniform particle dispersion. The films, mounted on running shoe soles, successfully detected different foot-strike patterns (heel strike, midfoot, and forefoot). This system demonstrates strong potential for wearable sensors in athletic monitoring and injury prevention.
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    High-performance triboelectric and piezoelectric nanogenerator enabled by BF-BT-NZN multifunctional ceramic filler
    (2025-10-01)
    Sumang, Rattiphorn
    ;
    Jantaratana, Pongsakorn
    ;
    Charoonsuk, Thitirat
    ;
    Vittayakorn, Naratip
    ;
    Bongkarn, Theerachai
    The development of efficient and flexible energy-harvesting materials is essential for advancing self-powered electronic devices. In this study, we report the fabrication of flexible composite films by incorporating (1-x)(0.75BiFeO<inf>3</inf>-0.25BaTiO<inf>3</inf>)-xNd(Zn<inf>0.67</inf>Nb<inf>0.33</inf>)O<inf>3</inf>,abbreviated as (BF-BT-NZN), ceramic powder into a PDMS matrix, with filler contents ranging from 5 to 25 wt%. The optimized 10 wt% composite film demonstrated a maximum output voltage of 112.24 V and a current of 5.69 µA approximately 11 and 18 times higher than pure PDMS, respectively. Following a poling treatment, the output further increased to 149.54 V and 10.71 µA. The film exhibited excellent flexibility and durability, enabling practical applications such as powering LEDs, a digital watch, and charging capacitors. These results highlight the potential of BF-BT-NZN/PDMS composites as high-performance materials for wearable energy-harvesting applications.
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    Flexible hybrid piezo/triboelectric energy harvester based on a lead-free BNT-BT-KNN ceramic-polymer composite film
    (2024-12-01)
    Panpho, Phakakorn
    ;
    Charoonsuk, Thitirat
    ;
    Vittayakorn, Naratip
    ;
    Bongkarn, Theerachai
    ;
    Sumang, Rattiphorn
    Environment-friendly piezoelectric micro/nanogenerators have attracted tremendous attention due to the increasing demand for portable self-power devices. Here, the [(0.94−x)Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>–0.06BaTiO<inf>3</inf>–xK<inf>0.5</inf>Na<inf>0.5</inf>NbO<inf>3</inf>; BNT-BT-xKNN] lead-free ceramic, at x = 0, 0.02, 0.04, 0.06, 0.08 and 0.10 mol%, was prepared via the solid-state method. The doping concentration x = 0.02 mol% shows the highest dielectric properties and the lowest dielectric loss. The active layer of the hybrid device is made by mixing BNT-BT-2KNN into the PDMS to form a series of polymer-ceramic composite films ranging from 7 to 19 wt% of BNT-BT-2KNN. The electrical response of the composite film is systematically studied with the addition of different weight percentages of the particles to the PDMS matrix. It was found that incorporating BNT-BT-2KNN at 11 wt% into the PDMS matrix exhibited the optimum harvesting performance, resulting in an output voltage and current density of about 30 V and 0.28 μA/cm<sup>2</sup>, respectively. The hybridized PENG and TENG devices could operate in a long-term cyclic mode, charge the capacitor for energy storage, and also light up LEDs. This research proposed a simple device fabrication and provided a guideline for the development of high-performance microgenerators, which is crucial for device development and practical use in the future.