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    Study on optical and electronic properties of Sn-doped ZnPc
    (2013-10-29) ;
    Sributr, Chaloempol
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    Rojanasuwan, Sunit
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    Sn doped ZnPc films were deposited on intrinsic Si and glass substrates by organic source thermal co-evaporation technique with different deposition rates. Optical properties and electronic structure were characterized by UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) respectively. The UV-Vis results showed that phase transition of ZnPc from α- phase to β-phase occurred when Sn:ZnPc deposition rate is 0.3:0.7 or higher. XPS results indicated that the outer s electron of Sn atom is transferred to the ZnPc. Broadening of the C 1s spectra is observed with the increasing of Sn deposition rate. This broadening corresponds to the change of molecular environment surrounding carbon atoms in the Sn-doped ZnPc films. © (2013) Trans Tech Publications, Switzerland.
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    Improved Efficiency of Polymer Solar Cells by means of Coating Hole Transporting Layer as Double Layer Deposition
    (2017-10-20)
    Chonsut, T.
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    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>.
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    The effect of the central metal atom on the structural phase transition of indium doped metal phthalocyanine
    (2013-08-30)
    Rojanasuwan, Sunit
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    Prajuabwan, Pakorn
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    Chanhom, Annop
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    Jaruvanawat, Anuchit
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    We investigate the effect of central metal atom on the phthalocyanine(Pc) molecular crystals as intercalated with indium. As dopant, indium has physical interaction with some atom in the ring of Pc molecule and there is charge transfer between indium atom and Pc ring atom. Since In-doped Pc is a hole doping which increase positive charge carriers and the HOMO of ZnPc, CuPc, NiPc and MgPc are localized on the phthalocyanine ring, then, the central metal atom e.g. Zn, Cu, Ni and Mg are not directly involved with the charge transfer between indium dopant and their Pc molecule. The structural phase transition from α phase to β phase of ZnPc upon doping with indium is another evidence for the existing of charge transfer between dopant atom and matrix Pc molecule. A comparative experiment of optical absorption spectrum of each metal Pc reveals that the central metal atom will affect the forming of crystal structure whether will be α phase or β phase as intercalated with indium. © (2013) Trans Tech Publications, Switzerland.
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    Study of optical and electrical properties of tin doped cobalt-phthalocyanine thin films prepared by thermal co-evaporation
    (2018-09-05) ;
    Jessadaluk, Sukittaya
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    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.
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    Study of nano Titanium (IV) oxide for Self-cleaning applications
    (2021-01-01)
    Koetniyom, W.
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    Bandansong, T.
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    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%.
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    Phase formation polycrystalline vanadium oxide via thermal annealing process under controlled nitrogen pressure
    (2017-10-20)
    Jessadaluk, S.
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    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>
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    Influence of the annealing temperature on the organometallic halide perovskite phase formation via CH3NH3Cl as additive in sequential deposition process.
    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.
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    Development of solution-based electrodes from nanocomposite material between PEDOT:PSS and ITO nanoparticles
    (2017-01-01)
    Watthanarungsarit, Kraisak
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    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.
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    Hole doping through indium intercalation into copper phthalocyanine
    (2013-10-29)
    Jaruvanawat, Anuchit
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    Prajuabwan, Pakorn
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    Rojanasuwan, Sunit
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    Chanhom, Annop
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    A blend of molecular acceptor and molecular donor made of Copper Phthalocyanine (CuPc) and Indium in various ratios were evaporated in high vacuum on to intrinsic silicon substrates by using vacuum thermal co-evaporation technique. Electronic properties of In-doped CuPc thin films have been examined by X-ray photoelectron spectroscopy (XPS). The results obtained by XPS suggests that In-doped CuPc is a hole transport material. © (2013) Trans Tech Publications, Switzerland.
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    Evidence of phase transition of indium doped Zinc phthalocyanine
    (2013-04-29)
    Rojanasuwan, Sunit
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    Prajuabwan, Pakorn
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    Chanhom, Annop
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    Jaruvanawat, Anuchit
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    A new intercalation of Indium and Zinc Phthalocyanine(ZnPc) thin films is developed by using thermal co-evaporation method. Optical characteristics of In-doped ZnPc are studied in comparison with pristine ZnPc, which shows improvement on optical absorption at the visible spectrum. The presence of a new phase transition upon Indium doping is examined and consequently support the idea of the intercalated phase upon doping. A Schottky diode made of Indium doped ZnPc is fabricated in order to measure its electrical properties, its photo-current spectrum confirms the existence of phase transition. © (2013) Trans Tech Publications, Switzerland.