Khemasiri, Narathon

Preferred name

Khemasiri, Narathon

Alternative Name

Khemasiri, N.

narathon.kh@kmitl.ac.th

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ZnO Nanorods Grown on Heterogenous Ag Seed Layers for Single-Cell Fluorescence Bioassays
(2021-07-23)
Muensri, Phitchaya
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Treetong, Alongkot
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Namdee, Katawut
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Kasamechonchung, Panita
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Wutikhun, Tuksadon
Here we demonstrate the controllability of the morphology of hydrothermal ZnO nanorods (ZnO-NRs) grown on heterogenous Ag seed layers. By varying the crystal orientation of silver thin films (Ag), a high density of ZnO-NRs could be obtained. We find that the density of ZnO-NRs strongly relates to the peak intensity ratio between (111) and (200) planes of Ag thin films due to a heteroepitaxy between (0002) ZnO and (111) Ag rather than that of grain boundary nucleation and/or surface nucleation. In addition, the optimized heterostructure of ZnO nanorod/Ag arrays is investigated via a critical concentration for nucleation and used as a fluorescence enhancement substrate (FES). The experimental results have shown that the FES presents an ability to detect a biological sample (PC-3 cell) with a high sensitivity and low detection limit of 1 cell/μL. Our results highlight that understanding an important key to control and design the morphology of heterogeneous hydrothermal ZnO-NR growth is essential to open up the opportunities for fundamental studies and applications in high-performance integrated nanodevices.
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Annealed zno/al2o3 core-shell nanowire as a platform to capture rna in blood plasma
(2021-07-01)
Takahashi, Hiromi
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Yasui, Takao
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Klamchuen, Annop
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Khemasiri, Narathon
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Wuthikhun, Tuksadon
RNA analytical platforms gained extensive attention recently for RNA-based molecular analysis. However, the major challenge for analyzing RNAs is their low concentration in blood plasma samples, hindering the use of RNAs for diagnostics. Platforms that can enrich RNAs are essential to enhance molecular detection. Here, we developed the annealed ZnO/Al<inf>2</inf>O<inf>3</inf> core-shell nanowire device as a platform to capture RNAs. We showed that the annealed ZnO/Al<inf>2</inf>O<inf>3</inf> core-shell nanowire could capture RNAs with high efficiency compared to that of other circulating nucleic acids, including genomic DNA (gDNA) and cell-free DNA (cfDNA). Moreover, the nanowire was considered to be biocompatible with blood plasma samples due to the crystalline structure of the Al<inf>2</inf>O<inf>3</inf> shell which serves as a protective layer to prevent nanowire degradation. Our developed device has the potential to be a platform for RNA-based extraction and detection.
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Effects of thermal treatment on hydrophilicity and corrosion resistance of Ti surface
(2019-03-01)
Boonrungsiman, Suwimon
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Prompinit, Panida
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Khemthong, Pongtanawat
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Wutikhun, Tuksadon
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Treethong, Alongkot
Surface treatment of titanium (Ti) surface has been extensively studied to improve its properties for biomedical applications, including hydrophilicity, corrosion resistance, and tissue integration. In this present work, we present the effects of thermal oxidation as surface modification method on metallic titanium (Ti). The Ti foils were oxidized at 300°C, 400°C, 500°C, and 600°C under air atmosphere for 3 hours, which formed oxide layer on Ti surface. The physicochemical properties including surface chemistry, roughness, and thickness of the oxide layer were evaluated in order to investigate how these factors affected surface hydrophilicity, microhardness, and corrosion resistance properties of the Ti surface. The results revealed that surfaces of all oxidized samples were modified by formation of titanium dioxide layer, of which morphology, phase, and thickness were changed according to the oxidized temperatures. Increasing oxidation temperature led to the formation of thicker oxide layer and phase transformation of anatase to rutile. The presence of the oxide layer helped the improvement of corrosion resistance and microhardness. The most improvement in surface roughness was found in the specimens treated at 400°C, which significantly improved surface hydrophilicity. But both surface roughness and hydrophilicity reduced when oxidized at 500°C and 600°C, suggesting that hydrophilicity was dominated by the surface roughness. In addition, this surface treatment did not reduce the biocompatibility of the metallic Ti substrates against murine osteoblasts (MC3T3).
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Modification of a photoanode by means of localized surface plasmon resonance from Au nanoparticles decorated on ZnO nanorods for photoelectrochemical applications
(2019-01-01)
Khemasiri, Narathon
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Soyeux, Nathan
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Rattanawarinchai, Prapakorn
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Jessadaluk, Sukittiya
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Klamchuen, Annop
Photoelectrochemical (PEC) activity is possibly enhanced by an increase in photocurrent generated from the photoanode. In this work, a modified photoanode that consists of zinc oxide nanorods (ZnO-NRs) decorated with gold nanoparticles (Au-NPs) is proposed to improve the generation of photocurrent. X-ray diffraction and scanning electron microscopy are employed to confirm the decoration of Au-NPs on well-aligned ZnO-NRs. A significant enhancement (∼4 times) in photocurrent density is obtained from the ZnO-NR photoanode decorated with Au-NPs compared to the bare ZnO-NR photoanode. Photoluminescence and UV-visible spectroscopy reveal that the improvement in photocurrent density results from (i) the decrease in charge recombination in the ZnO-NRs due to charge dissociation and (ii) the additional injection of charge from Au-NPs owing to localized surface plasmon resonance. This research presents the idea of taking the benefit from Au-NPs to enhance the photocurrent density in PEC applications through the decrease in charge recombination and the increase in charge injection.
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Selective formations of antimony-dopant for highly sensitive nitrogen dioxide responsive behavior of tin oxide-based chemiresistive sensor
(2025-02-15)
Rattanawarinchai, Prapakorn
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Khemasiri, Narathon
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Rahong, Sakon
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Rangkasikorn, Adirek
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Kayunkid, Navaphun
Here, selective formation of antimony (Sb) dopant species responsible for highly sensitive gas sensors based on tin oxide (SnO<inf>2</inf>) film grown via pulsed laser deposition is presented. By elevating a forming energy through controlling substrate temperature, not only crystallinity of Sb-SnO<inf>2</inf> (ATO) is notably enhanced but the Sb5 + also predominantly replace at Sn4+ site rather than Sb3+ counterpart. Such Sb-species selection plays a crucial role on the density of oxygen vacancy and free electron enabling to rationally design conductive behaviour of ATO film from insulative to degenerated semiconductor. As a practical example, detection of nitrogen dioxide (NO<inf>2</inf>) gas is selected as an application model. We found a narrow window for high NO<inf>2</inf> sensing performance of ATO film which strongly corresponds with the amount of carrier density. At certain window, ATO film exhibits high NO<inf>2</inf> response of 24.65 (10 ppm) and low limit of detection of 0.5 ppm, which is 5-fold higher and 10-fold lower than that of undoped-SnO<inf>2</inf>, respectively. Our finding demonstrates a facile approach to design over the chemical state, defect, and conductivity of the active sensing layer, allowing us to achieve an excellent sensing performance of functional materials conjugated to a nano-electronic platform.
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A tunable thermal switching device based on Joule heating-induced metal-insulator transition in VO2 thin films via an external electric field
(2019-01-01)
Jessadaluk, Sukittaya
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Khemasiri, Narathon
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Rattanawarinchai, Prapakorn
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Rahong, Sakon
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Rangkasikorn, Adirek
A solid state thermal switching device can regulate carrier transport by triggering of its critical transition temperature (T<inf>c</inf>) by applied external thermal energy. Continuous control of the T<inf>c</inf> of the thermal switch by the metal-insulator transition (MIT) phenomenon makes such devices widely usable. In this research, tunable thermal switching devices were fabricated, and characterization of the MIT in VO<inf>2</inf> thin film phase transition material was studied as a function of temperature and the external applied electric field. We observed reversible abrupt changes of the electrical resistivity by approximately three orders of magnitude at T<inf>c</inf> = 62.3 °C for VO<inf>2</inf> thin film on a SiO<inf>2</inf>/Si substrate. The MIT induced by the external electric field successfully controlled the T<inf>c</inf> of the thermal switch between 60 °C and 47 °C (as a linear relationship). We found that the Joule heating effect, rather than electric field breakdown, was a dominant mechanism due to the configuration of the device.
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Influence of Antimony Species on Electrical Properties of Sb-Doped Zinc Oxide Thin Films Prepared by Pulsed Laser Deposition
(2023-06-01)
Jessadaluk, Sukittaya
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Khemasiri, Narathon
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Kayunkid, Navaphun
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Rangkasikorn, Adirek
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Wirunchit, Supamas
This study systematically investigates the influence of antimony (Sb) species on the electrical properties of Sb-doped zinc oxide (SZO) thin films prepared by pulsed laser deposition in an oxygen-rich environment. The Sb species-related defects were controlled through a qualitative change in energy per atom by increasing the Sb content in the Sb<inf>2</inf>O<inf>3</inf>:ZnO-ablating target. By increasing the content of Sb<inf>2</inf>O<inf>3</inf> (wt.%) in the target, Sb3+ became the dominant Sb ablation species in the plasma plume. Consequently, n-type conductivity was converted to p-type conductivity in the SZO thin films prepared using the ablating target containing 2 wt.% Sb<inf>2</inf>O<inf>3</inf>. The substituted Sb species in the Zn site (Sb<inf>Zn</inf>3+ and Sb<inf>Zn</inf>+) were responsible for forming n-type conductivity at low-level Sb doping. On the other hand, the Sb–Zn complex defects (Sb<inf>Zn</inf>–2V<inf>Zn</inf>) contributed to the formation of p-type conductivity at high-level doping. The increase in Sb<inf>2</inf>O<inf>3</inf> content in the ablating target, leading to a qualitative change in energy per Sb ion, offers a new pathway to achieve high-performing optoelectronics using ZnO-based p–n junctions.
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Electroreflectance study of antimony doped ZnO thin films grown by pulsed laser deposition
(2021-10-01)
Jessadaluk, Sukittaya
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Khemasiri, Narathon
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Rattanawarinchai, Prapakorn
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Kayunkid, Navaphun
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Rahong, Sakon
In this research, antimony doped ZnO (SZO) thin films with various doping content have been grown on a c-Al<inf>2</inf>O<inf>3</inf> substrate by pulsed laser deposition. The effect of the applied electric field on the bandgap of SZO thin films was studied by electroreflectance (ER) spectroscopy using a capacitor-type geometry. Hall effect measurements indicate that the p-type conductivity of SZO is realized for the Sb<inf>2</inf>O<inf>3</inf> weight percentage at 2%. The blue shift of the energy bandgap was observed in thin films after increasing the doping concentration. The Burstein-Moss effect is the crucial mechanism for the blue shift of the SZO bandgap. Furthermore, we found the red shift of bandgap in all samples, which was measured under various electric fields by ER spectroscopy. The changes of the optical transition in the band structure should be the origin of the red shift behaviors of the SZO bandgap under the presence of the electric field. Based on our results, we can design and optimize the bandgap of SZO for optoelectronic devices.
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Laser-induced graphene electrochemical immunosensors for rapid and sensitive serological detection: A case study on dengue detection platform
(2025-06-01)
Inlumphan, Supawee
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Wongwiriyapan, Winadda
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Khemasiri, Narathon
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Rattanawarinchai, Prapakorn
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Leepheng, Piyawan
Here, we present a diagnostic on a chip platform based on laser-induced graphene (LIG) electrochemical immunosensors for serological detection. The electrochemical immunosensors are fabricated through CO<inf>2</inf> laser induction on polyimide (PI) sheets. Optimal electrochemical activity of LIG electrodes is obtained under optimized conditions of laser fluence. To verify the application, the serological detection platform was demonstrated. After functionalization with dengue virus (DENV) antigen, the LIG electrochemical immunosensors are able to sense the presence of mouse anti-flavivirus monoclonal (4G2) antibody in a wide linear working range of 25–20,000 ng/ml with the limit of detection (LOD) of 17.41 ng/ml. A specific recognition with 4G2 antibodies against with media protein and isotype is confirmed. Furthermore, the reliability of LIG electrochemical immunosensors compared to conventional enzyme-linked immunosorbent assay (ELISA) is verified through the NS1 antibodies identification in human blood serum clinical samples at room temperature. Our results highlight that the LIG-based electrode is a promising platform for electrochemical immunosensors, aimed at developing reliable and practical diagnostic tools for serological detection. These tools enable early diagnosis of infectious diseases, as well as non-invasive and rapid screening.
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Tailoring ZnO Nanostructures through Precursor Concentration and Hydrothermal Duration: A Pathway to Efficient Solar Water Splitting
(2026-11-10)
Borklom, Phanlapa
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Khemasiri, Narathon
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Jessadaluk, Sukittaya
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Rattanawarinchai, Prapakorn
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Kayunkid, Navaphun
This work investigated the formation of ZnO nanostructures on ITO substrates prepared by self-seeding hydrothermal synthesis for photoelectrochemical ( PEC) water splitting applications. The hydrothermal parameters, precursor concentration and hydrothermal time, were varied to explore their influences on ZnO crystallinity, morphology, and PEC performance. The combinations of X-ray diffraction and field emission scanning electron microscopy revealed highly oriented ZnO nanostructures with diverse morphologies, including small granules, nanorods, dense films, and hexagonal platelets. Topographic profiling of the morphological parameters revealed complex relationships between synthesis conditions and nanostructure characteristics, highlighting the importance of considering aggregation phenomena in substrate-based growth. This aggregation led to deviations from conventional crystal growth theory predictions, particularly for grain density and diameter evolution. PEC performance evaluation identified ZnO nanorods as the optimal morphology, exhibiting a photocurrent density of 0.182 mA/cm² at 0 V vs. Ag/AgCl. Further enhancement was achieved by decorating ZnO nanorods with CdS nanoparticles, resulting in a six-fold increase in photocurrent density (1.2 mA/cm²). This improvement is attributed to expanded light absorption and improved charge separation at the CdS/ ZnO interface. Our findings demonstrate the potential of rationally designed ZnO-based nanostructures in the advancement of solar-driven water splitting technologies and provide valuable insights for optimizing PEC systems through precise control of hydrothermal synthesis parameters, consideration of substrate-induced aggregation, and strategies for photoelectrochemical (PEC) water splitting applications.

Khemasiri, Narathon

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