Photoconductivity/dark conductivity studies of chlorogallium phthalocyanine thin films on interdigitated microcircuit arrays

Pankow, Joel; Arbour, C.; Dodelet, J. P.; Collins, Greg E.; Armstrong, Neal R.

doi:10.1021/j100134a018

Cited by 22 publications

(15 citation statements)

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“…Small changes in molecular packing in an otherwise homogeneous environment for each molecule could produce an energetically distinct site which can subsequently function as a trap site for either holes or electrons. 26 The effect of crystal morphology can be seen from the comparison of UPS data in the a-and /8-phase Pc's, as depicted in Figure 2. The demetalated and divalent metal phthalocyanines as-deposited in this study are generally believed to consist of microcrystalline particles in which the molecules are arranged in a herringbone structure (aor /8-phase structures).43-47 Different morphologies with different crystal structures are In Figure 2a the UPS data for a PcZn film is shown as-deposited in the -structure and after its thermal rearrangement to the /3-structure.…”

Section: Resultsmentioning

confidence: 99%

Correlation of Frontier Orbital Positions and Conduction Type of Molecular Semiconductors As Derived from UPS in Combination with Electrical and Photoelectrochemical Experiments

Schlettwein

Armstrong

1994

J. Phys. Chem.

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He I photoelectron spectra collected from selected phthalocyanine thin films on Au substrates have been used to determine the position of the highest occupied orbitals and threshold ionization potentials in the solid state. Relative as well as absolute positions are given. Chemical modifications of these dyes (substitution of nitrogen heteroatoms to create the pyrido-or pyrazinotetraazaporphyrin complexes, addition of electronwithdrawing substituents to the ring periphery) and changes in the crystal structure of the solid affect the size of the frontier orbital (band) gap and especially the absolute HOMO and LUMO energies. The influence of different substituents with varying electron-donating or electron-accepting properties is investigated in detail.Photoemission data are compared with redox potentials and molecular orbital (MO) calculations from the literature. The frontier orbital positions strongly correlate with the conduction type of the thin film, the nature of electrical property changes seen during interactions with gases such as 0 2 and NH3, and the photoelectrochemical properties in different aqueous electrolytes.

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Section: Resultsmentioning

confidence: 99%

Correlation of Frontier Orbital Positions and Conduction Type of Molecular Semiconductors As Derived from UPS in Combination with Electrical and Photoelectrochemical Experiments

Schlettwein

Armstrong

1994

J. Phys. Chem.

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“…The control experiment showed a slight but consistent increase in current for the second testing, most likely due to oxygen doping in the films, which is well documented in phthalocyanine materials, due to the slow introduction with time of partially oxidized Pcs, which act to "dope" the Pc film. [47][48][49][50] This doping acts to increase the drain currents but decrease the degree of saturation with time. Currents on the second chip, which underwent irradiation with 254-nm light to polymerize the film, consistently showed a decrease in current following the polymerization process [ Fig.…”

Section: Ofet Behavior For Films Of Pc 1 and Pcmentioning

confidence: 99%

Anisotropies in the electrical properties of rod-like aggregates of liquid crystalline phthalocyanines: Direct current conductivities and field-effect mobilities

et al. 2004

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The direct current (dc) conductivities and organic field-effect transistor (OFET) characteristics of a class of octa-substituted liquid crystalline (discotic mesophase) phthalocyanines (Pcs) are discussed. These molecules self-organize into columnar aggregates with large coherence lengths (up to approximately 300 nm). Langmuir–Blodgett films of these molecules were horizontally transferred to either interdigitated microelectrodes (IME) or OFET substrates, so that current flow could be measured either parallel or perpendicular to the column axis. Twenty-eight bilayer films of these Pcs on the IME substrates showed anisotropies in dc conductivity up to 50:1, whereas similar Pc films showed anisotropies in field effect mobilities of approximately 10:1, for a variety of W/L ratios (source/drain dimensions and spacing). Field-effect mobilities of 1 to 5 × 10-6 cm2·V-1·s-1 were determined from OFET measurements, along the Pc column axis, whereas charge mobilities measured from the space charge limited current regime on the IME substrates were in the range of 10-4 cm2·V-1·s-1. Conductive tip atomic force microscopy measurements on the apprximately 500-nm length scale showed that the conductivity anisotropy can be as high as 1000:1 when the Pc columns are intimately contacted to an adjacent Au bond pad.

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“…The study of the photoconductivity changes of ClGaPc and ClInPc films has been employed in improving the detection of NH 3 and NO 2 [26,27]. Note that in all cited work thermal evaporation was used as a conventional method for the deposition of thin films of unsubstituted metal phthalocyanines.…”

Section: Introductionmentioning

confidence: 99%

Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance

Evyapan

Kadem

Basova

et al. 2016

Sensors and Actuators B: Chemical

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This document is the author deposited version. You are advised to consult the publisher's version if you wish to cite from it. Published versionEVYAPAN, Murat, KADEM, Burak, BASOVA, Tamara V., YUSHINA, Irina V. and HASSAN, Aseel (2016). Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance. Sensors and Actuators B: Chemical, 236, 605-613. Copyright and re-use policySee http://shura.shu.ac.uk/information.html Sheffield Hallam University Research Archivehttp://shura.shu.ac.uk Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance AbstractIn this work, thin films of chloroaluminium phthalocyanine (ClAlPc), fluoroaluminium phthalocyanine (FAlPc) and fluorochromium phthalocyanine (FCrPc), which are insoluble in conventional solvents, were deposited by spin coating of their solutions in trifluoroacetic acid.The sensing response of these films versus acetic acid, three alcohols (methanol, ethanol, butanol) and three amines (methylamine, dimethylamine, trimethylamine) have been investigated using surface plasmon resonance as the sensing method. It has been shown that the sensor response of the investigated films decreases in the following order: acetic acid > alcohols > amines. The optical changes as monitored by SPR method have been used in conjunction with Fick's second law of diffusion to determine the diffusion coefficients of analyte vapor during the films' swelling process. The obtained results showed that the diffusion coefficients and the swelling characteristics of the films are dependent on the functional group of the phthalocyanine molecule and the molecular size of the analyte.

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Photoconductivity/dark conductivity studies of chlorogallium phthalocyanine thin films on interdigitated microcircuit arrays

Cited by 22 publications

References 0 publications

Correlation of Frontier Orbital Positions and Conduction Type of Molecular Semiconductors As Derived from UPS in Combination with Electrical and Photoelectrochemical Experiments

Correlation of Frontier Orbital Positions and Conduction Type of Molecular Semiconductors As Derived from UPS in Combination with Electrical and Photoelectrochemical Experiments

Anisotropies in the electrical properties of rod-like aggregates of liquid crystalline phthalocyanines: Direct current conductivities and field-effect mobilities

Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance

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