Rangkasikorn, Adirek
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Preferred name
Rangkasikorn, Adirek
Alternative Name
Rangkasikorn, A.
Main Affiliation
Email
adirek.ra@kmitl.ac.th
12 results
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Item type:Publication, Metal Oxide Nanostructures Enhanced Microfluidic Platform for Efficient and Sensitive Immunofluorescence Detection of Dengue Virus(2023-11-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The enhancement of sensitivity and response times of PDMS-based capacitive force sensor by means of active layer modification(2021-06-01); ; ; Jessadaluk, SukittiyaIn this work, sensitivity and response times of PDMS-based capacitive force sensors are enhanced via the modifications of the PDMS layer. Two modifying approaches are proposed; (i) change PDMS's (elastomer:curing agent) ratio and (ii) adding conductive polymer PEDOT:PSS into the PDMS layer. The change of PDMS (elastomer:curing agent) ratio from (10:1) to (30:1) increases the sensitivity from 0.4 0.08 to 0.72 0.23 kPa-1 (+80%) but it does not significantly affect the response/recovery times. In addition, by adding 1% wt. of PEDOT:PSS to PDMS (30:1), the further increment of sensitivity from 0.72 0.23 to 1.44 0.17 kPa-1 (+100%) and the shorter response time from 1.59 0.02 to 0.45 0.03 s (-72%) are observed. The mechanical and electrical studies reveal that the change of PDMS (elastomer:curing agent) ratio and the adding of PEDOT:PSS to PDMS layer result in the modification of PDMS's deformability and the increase of charge transportation, leading to the enhancement of sensing characteristics of the sensors. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Dragon Fruit Peels on the Synthesis of Antibacterial Nano Zinc Oxide (Nano-ZnO) via Green Synthesis Method(2026-05-20); ; This research focused on adding value to dragon fruit peel waste by utilizing it in the synthesis of antibacterial nano zinc oxide (Nano-ZnO) through a green synthesis process. In this study, all the dragon fruit peels were extracted using the solvent extraction technique with three different solvents (deionized water, ethanol, and methanol) for 1, 2, 3, 4, and 5 h, respectively. The amount of flavonoids from the extract was determined using UV-Vis spectrophotometer to obtain the optimum extraction time, which was 4 h for DI water as the solvent. Moreover, antibacterial Nano-ZnO was synthesized successfully by a green synthesis process using zinc nitrate Zn(NO3)2 and the extracts. The molecular vibrations as well as the crystal structure and morphology were investigated by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM), respectively. Additionally, the antibacterial efficacy of the nano-zinc oxide samples was evaluated using disc diffusion method. Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were the test agents. The research shows that the X-ray diffraction patterns of all synthesized ZnO nanoparticles (NPs) exhibited a wurtzite (hexagonal) crystal structure. FT-IR spectroscopy confirmed the presence of Zn-O stretching vibrations at approximately 500 cm⁻¹. Furthermore, the FE-SEM reveals that ZnO-yellow particles displayed spherical morphologies with an average particle size of 145 nm. At the same time, ZnO-White and ZnO-Red nanoparticles exhibited a combination of rod-like and elliptical morphologies, with average particle sizes of 168 nm and 321 nm, respectively. In addition, the antibacterial activity demonstrates effective inhibition against S. aureus and E. coli in all three ZnO nanoparticle conditions. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study of nano Titanium (IV) oxide for Self-cleaning applications(2021-01-01); This research is study the fabrication of a composite film between Polydimethylsiloxane (PDMS) and Titanium (IV) oxide nanoparticles for self-cleaning applications via the spin coating process. This study has focused on the optimum ratio between PDMS and Titanium (IV) oxide and the optimum speed for the spin coating process, especially in order to obtain a composite film with outstanding self-cleaning surface properties. After that, the prepared composite films were studied by UV-Vis spectrometer, water contact angle measurement and solar simulator. Self-cleaning properties was investigated from the testing of wetting properties and measuring the water contact angle. Furthermore, the organic degradation properties were examined by degradation of methylene blue under UV light via solar. From this research was found that the PDMS/Titanium oxide (IV) at 4:3 ratio is the most optimum condition for the fabrication of a composite film by observing with the degradation of methylene blue has showed the highest the degradable efficiency is 55.59%. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Selective formations of antimony-dopant for highly sensitive nitrogen dioxide responsive behavior of tin oxide-based chemiresistive sensor(2025-02-15); ; ; 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 Sb<sup>5 +</sup> also predominantly replace at Sn<sup>4+</sup> site rather than Sb<sup>3+</sup> 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Antimony Species on Electrical Properties of Sb-Doped Zinc Oxide Thin Films Prepared by Pulsed Laser Deposition(2023-06-01); ; ; 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, Sb<sup>3+</sup> 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><sup>3+</sup> and Sb<inf>Zn</inf><sup>+</sup>) 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Electroreflectance study of antimony doped ZnO thin films grown by pulsed laser deposition(2021-10-01); ; 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhancement of sensing characteristics of Polydimethylsiloxane-based capacitive force sensor by introducing conductive polymer to dielectric layer(2021-01-01); ; ; Jessadaluk, SukittayaA capacitive force sensor is one of the electronics components used in several electronic devices and applications. An improvement of sensing characteristics of the sensor, for example sensitivity and response time, becomes an interesting research topic. The alternative approach to enhance the sensitivity and response time of polydimethylsiloxane-based capacitive force sensors is proposed by introducing poly(3,4-ethylenedioxythiophene) polystyrene sulphonate, a conductive polymer, into polydimethylsiloxane active layer. Two sensors using different active layers, (i) polydimethylsiloxane (conventional sensor) and (ii) poly(3,4-ethylenedioxythiophene) polystyrene sulphonate mixed polydimethylsiloxane (modified sensor), were fabricated and characterised to reveal the sensing enhancement. Interestingly, the modified sensor shows the significant increase in the sensitivity from 0.7 to 1.14 kPa<sup>–1</sup> (+62.86%) and the shortening response time from 1.55 to 0.43 s (−72.26%) with respect to the conventional sensor. In addition, the deterioration in elastic behaviour and the faster charge–discharge behaviour observed from the poly(3,4-ethylenedioxythiophene) polystyrene sulphonate mixed polydimethylsiloxane film indicate the better deformation and charge transport than that from polydimethylsiloxane film. Therefore, it can be concluded that the conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate additive plays the role of mechanical and electrical modification of the polydimethylsiloxane active layer leading to the enhancement in sensitivity and response time of the polydimethylsiloxane-based capacitive force sensor. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Tailoring ZnO Nanostructures through Precursor Concentration and Hydrothermal Duration: A Pathway to Efficient Solar Water Splitting(2026-11-10); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Growth window and metal-insulator transition behavior of VO2 thin films deposited by pulsed laser deposition for thermal switch applications(2026-05-01); ; ; Vanadium dioxide (VO<inf>2</inf>) is a strongly correlated transition metal oxide that exhibits a sharp and reversible metal-insulator transition (MIT) near room temperature, making it a promising material for thermal switching and adaptive electronic applications. In this study, VO<inf>2</inf> thin films were deposited on single-crystalline Si, thermally grown SiO<inf>2</inf>, and fused quartz substrates by pulsed laser deposition, and the influence of substrate temperature and oxygen partial pressure on phase formation, structural properties, and MIT behavior was systematically investigated. By optimizing deposition conditions within a narrow oxygen pressure window, phase-pure monoclinic VO<inf>2</inf>(M) thin films with high crystalline quality were achieved while suppressing the formation of over-oxidized vanadium oxide phases. Structural and chemical analyses using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the stabilization of the V4+ oxidation state and uniform film stoichiometry. Temperature-dependent electrical measurements revealed a pronounced and reproducible MIT characterized by an abrupt change in resistance and a clear thermal hysteresis. In-situ temperature-dependent X-ray diffraction further demonstrated a direct correlation between the monoclinic-rutile structural transformation and the electronic transition. Importantly, the MIT behavior was consistently observed across all investigated substrates, indicating robust film growth and substrate tolerance. These results provide insight into the structure-property relationships governing VO<inf>2</inf> thin films and highlight their potential for integration into thermal switch and thermally adaptive device architectures.