Kayunkid, Navaphun
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Kayunkid, Navaphun
Alternative Name
Kayunkid, N.
Kayunkid, Nawapun
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navaphun.ka@kmitl.ac.th
17 results
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Item type:Publication, Highly crystalline films of PCPDTBT with branched side chains by solvent vapor crystallization: Influence on opto-electronic properties(2015-02-18); Tornow, Benjamin(Figure Presented) PCPDTBT, a marginally crystallizable polymer, is crystallized into a new crystal structure using solvent-vapor annealing. Highly ordered areas with three different polymer-chain orientations are identified using TEM/ED, GIWAXS, and polarized Raman spectroscopy. The optical and structural properties differ significantly from films prepared by standard device preparation protocols. Bilayer solar cells, however, show similar performance. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Improved Efficiency of Polymer Solar Cells by means of Coating Hole Transporting Layer as Double Layer Deposition(2017-10-20); ; ; Polymer solar cells is one of the promising technologies that gain tremendous attentions in the field of renewable energy. Optimization of thickness for each layer is an important factor determining the efficiency of the solar cells. In this work, the optimum thickness of Poly(3,4-ethylenedioxythione): poly(styrenesulfonate) (PEDOT:PSS), a famous polymer widely used as hole transporting layer in polymer solar cells, is determined through the analyzing of device's photovoltaic parameters, e.g. short circuit current density (J<inf>sc</inf>), open circuit voltage (V<inf>oc</inf>), fill factor (FF) as well as power conversion efficiency (PCE). The solar cells were prepared with multilayer of ITO/PEDOT:PSS/PCDTBT:PC<inf>70</inf>BM/TiO<inf>x</inf>/Al by rapid convective deposition. In such preparation technique, the thickness of the thin film is controlled by the deposition speed. The faster deposition speed is used, the thicker film is obtained. Furthermore, double layer deposition of PEDOT:PSS was introduced as an approach to improve solar cell efficiency. The results obviously reveal that, with the increase of PEDOT:PSS thickness, the increments of J<inf>sc</inf> and FF play the important role to improve PCE from 3.21% to 4.03%. Interestingly, using double layer deposition of PEDOT:PSS shows the ability to enhance the performance of the solar cells to 6.12% under simulated AM 1.5G illumination of 100 mW/cm<sup>2</sup>. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Modification of a photoanode by means of localized surface plasmon resonance from Au nanoparticles decorated on ZnO nanorods for photoelectrochemical applications(2019-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study of structural and optical properties of PbS thin films(2018-01-01); This research aimed to synthesize lead sulfide (PbS) thin films on glass slides using the successive ion layer absorption and reaction (SILAR) method. We studied the optical properties and structure of PbS thin films by changing the number of dipping cycles and the concentration of precursor solution. The results of this experiment show that different conditions have a considerable influence on the thickness and absorbance of the films. When the number of dipping cycles and the concentration of the solution are increased, film thickness and absorbance tend to become higher. The xrays diffraction pattern showed all the diffraction peaks which confirmed the face center cubic and the structure of PbS had identified. Grain size computation was used to confirm how much these conditions could be affected. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study of optical and electrical properties of tin doped cobalt-phthalocyanine thin films prepared by thermal co-evaporation(2018-09-05); ; ; The aim of this research is to study the specific properties e.g. surface morphology, optical absorption as well as electrical conductivity of tin-doped cobalt-phthalocyanine (CoPc) thin film prepared by thermal co-evaporation. The concentration of tin metal dopant is controlled via evaporation rate during film's preparation. The change of tin quantity leads to the significant changes not only in morphology but also in molecular packing of the doped films. Moreover, the dramatic increase in both carrier mobility and carrier concentration should provide the enhancement in electrical conductivity of the doped films. By controlling the specific properties of the tin-doped CoPc thin film, the increasing efficiency of optoelectronic applications based on metal-phthalocyanine could be achieved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Phase formation polycrystalline vanadium oxide via thermal annealing process under controlled nitrogen pressure(2017-10-20); ; ; This article provides an approach to improve and control crystal phases of the sputtering vanadium oxide (V<inf>x</inf>O<inf>y</inf>) thin films by post-thermal annealing process. Usually, as-deposited V<inf>x</inf>O<inf>y</inf> thin films at room temperature are amorphous phase: post-thermal annealing processes (400 °C, 2 hrs) under the various nitrogen (N<inf>2</inf>) pressures are applied to improve and control the crystal phase of V<inf>x</inf>O<inf>y</inf> thin films. The crystallinity of V<inf>x</inf>O<inf>y</inf> thin films changes from amorphous to α-V<inf>2</inf>O<inf>5</inf> phase or V<inf>9</inf>O<inf>17</inf> polycrystalline, which depend on the pressure of N<inf>2</inf> carrier during annealing process. Moreover, the electrical resistivity of the V<inf>x</inf>O<inf>y</inf> thin films decrease from 10<sup>5</sup> Ω cm (amorphous) to 6×10<sup>-1</sup> Ω cm (V<inf>9</inf>O<inf>17</inf>). Base on the results, our study show a simply method to improve and control phase formation of V<inf>x</inf>O<inf>y</inf> thin films<inf>.</inf> - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 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); ; 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Controlling the growth of silver nanoparticles on thin films of an n-type molecular semiconductor(2015-06-11) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of the annealing temperature on the organometallic halide perovskite phase formation via CH3NH3Cl as additive in sequential deposition process.(2019-01-01); ; ; Organometallic halide perovskite materials with the general formula ABX<inf>3</inf> have been recently interested as active layers in perovskite solar cells. It is well known that the O<inf>2</inf> is the main problem for fabricated perovskite solar cells. Usually, the perovskite thin film need to be prepared in the N<inf>2</inf> atmosphere or in the glove box. In this research, the metal halide perovskite CH<inf>3</inf>NH<inf>3</inf>PbI<inf>2</inf>Cl thin films were successfully deposited using spin-coating technique via a single step solution deposition and CH<inf>3</inf>NH<inf>3</inf>Cl as additive in sequential deposition process in the open air. The effect of annealing temperature on the organolead halide perovskite phase formation of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>2</inf>Cl thin film was investigated. The phase formation as well as crystal structure were investigated by X-ray diffractometer, and we found that organolead halide perovskite thin film exhibited a pure phase perovskite without the unwanted phases. The crystallinity of the perovskite thin film was enhanced significantly by increasing the annealing temperature, and a single phase of the perovskite phase was observed by increment of the annealing temperature that is above 100<sup>O</sup>C. In addition to this, the growth of crystallinity in the halide perovskite thin film was increased with increasing heat treatment temperature. Furthermore, the morphology variation of the thin films were examined by Field Emission Scanning Electron Microscopy. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Development of solution-based electrodes from nanocomposite material between PEDOT:PSS and ITO nanoparticles(2017-01-01); ; ; Electrodes based on low-temperature preparation such as ink jet printing have been famously used in plastic electronic devices. The aim of this work is to investigate the specific properties of composite materials between nanoparticles of indium tin oxide (np-ITO) and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as an alternative electrode for plastic electronic devices. The composite materials were prepared as a function of np-ITO concentration varied from 1 to 20 w/v%. The 1x1 cm<sup>2</sup> hybrid electrodes were fabricated by drop casting method on the microscope slide. This method offers many advantages, including simple preparation, low manufacturing cost and short fabricating time. The electrical resistance of the hybrid films was measured using two-probe measurement. Moreover, the surface morphology of the composited film was explored by optical microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results clearly suggest that mixing np-ITO with PEDOT:PSS can significantly improve conductivity of the composited system. Average value of electrical resistance measured from np-ITO, PEDOT:PSS and composite film are 87.58 kΩ, 40.33 kΩ and 393 Ω, respectively. The significant reduction of film resistance can be explained by the conducting paths made up by PEDOT:PSS to connect np-ITO domain.