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    XPS investigation of an increasing C-H vibration of pentacene doped with indium
    (2013-10-29)
    Chanhom, Annop
    ;
    Prajuabwan, Pakorn
    ;
    Rojanasuwan, Sunit
    ;
    Jaruvanawat, Anuchit
    ;
    Rangkasikorn, Adirek
    We investigate the increase of C-H vibration in benzene rings of pentacene molecule upon doping with indium by the X-ray photoelectron spectroscopy (XPS) characterization technique. The risen of C-H vibration spectral component is employed to demonstrate the charge transfer between In dopant atoms and C atoms in benzene rings of pentacene molecule. This experiment can be used to explain the same mechanism of charge transfer between In dopant atoms and C atoms in In-doped nickel-phthalocyanine(NiPc). © (2013) Trans Tech Publications, Switzerland.
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    Hole doping through indium intercalation into copper phthalocyanine
    (2013-10-29)
    Jaruvanawat, Anuchit
    ;
    Prajuabwan, Pakorn
    ;
    Rojanasuwan, Sunit
    ;
    Chanhom, Annop
    ;
    Rangkasikorn, Adirek
    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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    The effect of the central metal atom on the structural phase transition of indium doped metal phthalocyanine
    (2013-08-30)
    Rojanasuwan, Sunit
    ;
    Prajuabwan, Pakorn
    ;
    Chanhom, Annop
    ;
    Jaruvanawat, Anuchit
    ;
    Rangkasikorn, Adirek
    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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    Exciton dissociation at Indium Tin Oxide/Indium doped zinc phthalocyanine interface
    (2013-04-29)
    Prajuabwan, Pakorn
    ;
    Rojanasuwan, Sunit
    ;
    Chanhom, Annop
    ;
    Jaruvanawat, Anuchit
    ;
    Rangkasikorn, Adirek
    A new intercalation of Indium and zinc phthalocyanine(ZnPc) thin film is developed by using thermal co-evaporation technique. The exciton dissociation at the interface of Indium Tin Oxide(ITO) electrode and Indium doped ZnPc upon laser irradiation is observed through the transient photovoltage measurement technique in comparison with the interfacial exciton dissociation occurred at ITO/pristine ZnPc interface. The occurring transient photovoltage spike is regarded as the effect of exciton dissociation at ITO/In-doped ZnPc interface and depends on the amount of free carrier separation by built-in field or charge carrier concentration according to doping ratio. The experiments demonstrate the existence of exciton dissociation at ITO/In-doped ZnPc interface, the direction of charges transfer is that holes are injected to ITO, whereas electrons are left in bulk film. A thin insulating layer of 6 nm thick lithium fluoride(LiF) is inserted between ITO and In-doped ZnPc to prevent the exciton dissociation at ITO/In-doped ZnPc interface and insist on the phenomenon of interfacial exciton dissociation. Further photoelectron spectroscopy experiments prove that In-doped ZnPc is 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
    ;
    Prajuabwan, Pakorn
    ;
    Chanhom, Annop
    ;
    Jaruvanawat, Anuchit
    ;
    Rangkasikorn, Adirek
    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.
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    Hole doping through indium intercalation into nickel phthalocyanine
    (2013-04-29)
    Prajuabwan, Pakorn
    ;
    Rojanasuwan, Sunit
    ;
    Chanhom, Annop
    ;
    Jaruvanawat, Anuchit
    ;
    Rangkasikorn, Adirek
    A new intercalation of indium and nickel phthalocyanine(NiPc) thin films is developed by using thermal co-evaporation technique. X-ray diffractometer(XRD) and optical absorption spectroscopy of In-doped NiPc suggest the crystal structure of In-doped NiPc is α-phase as same as that of pristine NiPc. Current-voltage characteristic of Shottky diode fabricated with In-doped NiPc thin film shows the enhancement of charge carrier concentration due to indium doping. Further photoelectron spectroscopy experiments prove that In-doped NiPc is hole transport material. © (2013) Trans Tech Publications, Switzerland.
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    ITO thin films prepared by gas-timing RF magnetron sputtering for transparent flexible antenna
    (2007-08-28)
    Prajuabwan, Pakorn
    ;
    Porntheeraphat, Supanit
    ;
    Klamchuen, Annop
    ;
    Nukeaw, Jiti
    The transparent flexible plastic antenna was fabricated. Indium tin oxide (ITO) thin film was deposited on flexible plastic substrate at room temperature by radio frequency (RF) magnetron sputtering with a new technique, called gas-timing. By using the x-ray diffraction (XRD) measurement of the ITO thin film grown by this technique, a cubic nano-crystalline structure with predominant (222) orientation was observed. The technique of gas-timing we used, the ITO thin film on flexible substrate was achieved with high transmittance in visible region of 90% and low resistivity. The performance of the new film antenna was studied experimentally with its return loss and radiation patterns. © 2007 IEEE.