Phase behaviour of copper and zinc phthalocyanines

Mohammed, K.A.; Collins, R. A.

doi:10.1016/0040-6031(86)85210-8

Cited by 19 publications

(3 citation statements)

References 11 publications

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“…Optical properties of CuPc have been studied in thin film form [23]. Many have reported the phase transition aspects on heat treatment using differential scanning calorimetry and infrared absorption spectroscopy [24,25]. Hassan and Gould [25] have reported (001) oriented aCuPc phase for films of thickness 0.1 mm or less.…”

Section: Introductionmentioning

confidence: 99%

Structural Investigation of Copper Phthalocyanine Thin Films Using X-Ray Diffraction, Raman Scattering and Optical Absorption Measurements

Prabakaran¹,

Kesavamoorthy

Reddy

et al. 2002

phys. stat. sol. (b)

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Structural properties of copper phthalocyanine (CuPc) powder and its thin films coated on glass plate are investigated using X-ray diffraction, Raman scattering and optical absorption techniques. These experiments are carried out at room temperature on CuPc powder and as-coated, 320 C and 520 C annealed, CuPc thin films. From the X-ray diffraction (XRD), we find that the CuPc powder exists in monoclinic phase, as-coated film is in orthorhombic a-phase and the film annealed at 320 C exists in monoclinic b-phase with different lattice parameters as compared to those of the powder phase. The XRD peaks in 520 C annealed film do not show the presence of CuPc but indicate the presence of copper oxide (CuO) nanoclusters of approximately 15 nm size. The optical Raman phonon frequencies of CuPc powder, as-coated and 320 C annealed CuPc films show a slight shift in the intramolecular high frequency modes. Whereas, their low frequency Raman spectra from intermolecular modes are characteristically different indicating different phases. The different characteristic behavior of the optical absorption spectra of the as-coated and 320 C annealed CuPc films corroborate the structural changes in the annealed film.

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Section: Introductionmentioning

confidence: 99%

Structural Investigation of Copper Phthalocyanine Thin Films Using X-Ray Diffraction, Raman Scattering and Optical Absorption Measurements

Prabakaran¹,

Kesavamoorthy

Reddy

et al. 2002

phys. stat. sol. (b)

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“…Copper phthalocyanine (CuPc) and nickel phthalocyanine (NiPc) deposited at substrate temperatures of 5 to 15 "C d o not undergo an a to p phase transition, even after heating at 300 "C for several hours [5]. Mohammed and Collins [6] have observed that both zinc phthalocyanine (ZnPc) and CuPc bulk samples undergo a two-stage phase transition. For example ZnPc remains a-form when heated above approximately 250 "C and is p-form when heated above approximately 340 "C. When heated to a maximum temperature between these two values the material attains an intermediate metastable form.…”

Section: Introductionmentioning

confidence: 99%

Structure and phase-change phenomena in evaporated thin films of cobalt phthalocyanine

Shihub¹,

Gould²

1993

Phys. Stat. Sol. (a)

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The structures of thin films of cobalt phthalocyanine (CoPc) which have been deposited onto glass substrates at room temperature are investigated. Films of thickness 0.1 μm are primarily of the α‐form and show a single Bragg peak indicating a strong preferential orientation in either the [001] or [200] directions, depending on whether the structure is tetragonal or orthorhombic. Films of thickness 1 μm show a slight decrease in the degree of preferential orientation, with the appearance of several additional peaks. After annealing at approximately 300 °C much of the material undergoes a phase transition to the stable β‐form, preferentially oriented in the [001] direction, while annealing at lower temperatures produces a mixture of the α‐ and β‐phases. The mean crystallite grain size increases systematically with maximum annealing temperature from approximately 30 nm without annealing to a maximum of approximately 100 nm when annealed at 315 °C.

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“…A phase transition to the thermodynamically stable β-phase was induced by heating the samples for several hours at 575 K as has been reported previously. − MIR transmission of the β-phase thin films shows a clear shift of the mode around 725 cm –1 as compared to the α-phase, and the appearance of a new mode at 780 cm –1 , see Figure . , …”

Section: Methodsmentioning

confidence: 55%

Strong Photophysical Diversity and the Role of Charge Transfer Excitons in Transition Metal Phthalocyanine β-Phases

et al. 2021

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The photophysics of the three transition metal phthalocyanines NiPc, CuPc and ZnPc in their β-phase has been studied using complementary experimental techniques: photoluminescence, optical absorption and electronenergy-loss spectroscopy. We demonstrate that the strongly different photoluminescence signal can be understood based on the different exciton dispersions, and that tiny differences in the structure and thus the intermolecular orbital overlap is able to model these differences. Our results clearly indicate a significant admixture of charge-transfer excitations to the lowest exciton state. They additionally demonstrate the need of a detailed microscopic understanding of organic semiconductors for their application potential.

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Phase behaviour of copper and zinc phthalocyanines

Cited by 19 publications

References 11 publications

Structural Investigation of Copper Phthalocyanine Thin Films Using X-Ray Diffraction, Raman Scattering and Optical Absorption Measurements

Structural Investigation of Copper Phthalocyanine Thin Films Using X-Ray Diffraction, Raman Scattering and Optical Absorption Measurements

Structure and phase-change phenomena in evaporated thin films of cobalt phthalocyanine

Strong Photophysical Diversity and the Role of Charge Transfer Excitons in Transition Metal Phthalocyanine β-Phases

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