Annealing effects on lead-phthalocyanine thin film as a toxic gas sensor

Sadaoka, Yoshihiko; Göpel, Wolfgang; Suhr, Barbara; Rager, A.

doi:10.1007/bf00721623

Cited by 10 publications

(2 citation statements)

References 8 publications

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“…To analyze the crystal structure of the heated films, the following regions of the FT-IR spectra have been reported in Figure : 1190−1050, 975−840, and 800−700 cm -1 . In fact, it is well-known that α and β polymorphs of MPcs are characterized by some IR peaks related to the short-range neighbor interactions. − As can be seen, the out-of-plane hydrogen bending mode (γ(C−H)) peak, which is centered at 726 cm -1 in the sample ASDEP, undergoes a splitting in two components centered at 731 cm -1 (β phase) and 722 cm -1 (α phase) ever since 30 min. At increasing heating time the two peaks become more resolved and the relative intensity of the peak at 722 cm -1 decreases until it becomes a small shoulder of the other peak in the spectrum of the sample 290C14h.…”

Section: Resultsmentioning

confidence: 98%

Effects of Heat Treatments on the Properties of Copper Phthalocyanine Films Deposited by Glow-Discharge-Induced Sublimation

et al. 2006

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Copper phthalocyanine films have been deposited by glow-discharge-induced sublimation. The films have undergone postdeposition heat treatments in air at 250 and 290 °C for different times, ranging from 30 min to 14 h. The properties of as-deposited and heated films have been investigated by different techniques in order to determine the effects of heat treatments on the film properties. Fourier transform infrared analysis and UV-visible optical absorption analysis point out a gradual evolution of the film structure from a mixture of R and β polymorphs to the only β polymorph in the sample heated at 290 °C for 14 h. A pronounced decrease of carbon and nitrogen atomic percentages against an oxygen increase in the heated films are shown by ion beam analyses (Rutherford backscattering spectrometry and nuclear reaction analysis) and X-ray photoelectron spectroscopy (XPS). X-ray absorption spectroscopy and XPS indicate that part of the copper phthalocyanine molecules decompose during heat treatments and the formation of copper oxide takes place. The replacement of copper phthalocyanine by copper oxide in the heated films accounts for the change of their surface electrical conductance and of their electrical response to NO 2 .

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Section: Resultsmentioning

confidence: 98%

Effects of Heat Treatments on the Properties of Copper Phthalocyanine Films Deposited by Glow-Discharge-Induced Sublimation

et al. 2006

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“…The structure of the deposited films has also been studied by FT-IR analysis. It is well-known that the MPc α and β polymorphs are characterized by some selected IR peaks related to the short-range neighbor interactions. ,, The IR spectra (region 1190−700 cm -1 ) of both as-deposited VE films, the RTVE film treated at 290 °C, and the GDS film are compared in Figure . According to Sidorov and Kotlyar, the peculiar IR features of CuPc α and β polymorphs are (i) the out-of-plane hydrogen bending mode (γ(C−H)) peak at 722 cm -1 (α) and 730 cm -1 (β); (ii) the peak at 770 cm -1 (α) and at 780 cm -1 (β), which has been ascribed to a vibrational mode of the central part of the CuPc cycle; (iii) the unresolved peaks at 864 and 870 cm -1 and the peak at 940 cm -1 (α) against the peaks at 877 and 957 cm -1 (β); and (iv) a peak at 1100 cm -1 and a shoulder at 1174 cm -1 , which are characteristic of the β polymorph.…”

Section: Resultsmentioning

confidence: 99%

Deposition of Copper Phthalocyanine Films by Glow-Discharge-Induced Sublimation

et al. 2005

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Copper phthalocyanine (CuPc) thin films have been deposited by a recently developed plasma-based method named glow-discharge-induced sublimation (GDS). The deposition of CuPc films has also been obtained by vacuum evaporation (VE) and the comparison of the two methods shows important structural differences. FT-IR and ion beam analyses (RBS-ERDA) show that the GDS-deposited films mainly consist of integer CuPc molecules, but at increasing deposition time the incorporation of damaged molecules becomes important. X-ray diffraction, FT-IR spectroscopy, and UV−vis analysis are used to study the microstructure of the CuPc films and point out that while the VE films consist of only α crystallites, a more disordered structure with the presence of both α and β polymorphs characterizes the GDS films. The latter films are also much more porous as shown by nitrogen physisorption measurements and SEM. Thermal treatments of the GDS films determine a decrease of the structural disorder at 250 °C and the complete transformation to the β polymorph at 290 °C.

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Schottky Barrier Formation and Electrical Transport in Oxygen-Doped Triclinic Lead Phthalocyanine Films

Ahmad

Collins

1991

Phys. Stat. Sol. (a)

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The electrical properties of oxygen‐doped thin films of triclinic lead phthalocyanine with mixed (Al, Au) electrodes are studied. AuPbPcAl and AlPbPcAu structures show different behaviour due to the varying oxygen distributions in the PbPc and the existence of an interfacial aluminium oxide layer in the latter case. At low voltages both types of device show Schottky diode behaviour. For AuPbPcAl structures the model of Cheung and Cheung is used to derive diode parameters. Barrier heights and widths are determined as a function of applied voltage and trap densities, hole concentrations, and the temperature parameter of the trapping are found to be consistent with reported values. The present results emphasise the role of oxygen doping and interfacial oxide layers in determination of the electrical behaviour of PbPc based devices.

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Annealing effects on lead-phthalocyanine thin film as a toxic gas sensor

Cited by 10 publications

References 8 publications

Effects of Heat Treatments on the Properties of Copper Phthalocyanine Films Deposited by Glow-Discharge-Induced Sublimation

Effects of Heat Treatments on the Properties of Copper Phthalocyanine Films Deposited by Glow-Discharge-Induced Sublimation

Deposition of Copper Phthalocyanine Films by Glow-Discharge-Induced Sublimation

Schottky Barrier Formation and Electrical Transport in Oxygen-Doped Triclinic Lead Phthalocyanine Films

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