Highly ordered titanyl phthalocyanine films grown by directional crystallization on oriented poly(tetrafluoroethylene) substrate

被引:71
作者
Brinkmann, M
Wittmann, JC
Barthel, M
Hanack, M
Chaumont, C
机构
[1] Inst Charles Sadron, F-67083 Strasbourg, France
[2] Univ Tubingen, Inst Organ Chem, D-72076 Tubingen, Germany
[3] Ecole Chim Polymeres & Mat Strasbourg, F-67000 Strasbourg, France
关键词
D O I
10.1021/cm011241o
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Highly oriented films of titanyl phthalocyanine (TiOPc) were obtained by high-vacuum sublimation onto an oriented poly(tetrafluoroethylene) (PTFE) substrate. The dependence of the structure and morphology on deposition parameters (substrate temperature T-s, deposition time t, and deposition rate tau) was followed by X-ray diffraction, transmission electron microscopy (TEM), and atomic force microscopy (AFM) to uncover the origin of the oriented growth process. At T-8 = 100 degreesC, an original growth mechanism was observed whereby alpha-TiOPc microcrystallites were formed by the static coalescence and reorganization of small amorphous aggregates in close contact. Nucleation of alpha-TiOPc is initiated at the PTFE macrosteps from which oriented crystallization propagates, leading to uniform a-TiOPc films with a twinned texture and a dense (0 1 0) contact plane. The molecules are in an edge-on orientation, with their molecular plane oriented parallel to the PTFE chains. At the mesoscale, the nucleation of crystalline a-TiOPc involves the alignment and oriented coalescence of amorphous prenucleation aggregates along the PTFE macrosteps, i.e., a graphoepitaxial process. At the molecular scale, it is proposed that the TiOPc orientation and the preferential nucleation of the a polymorph are enforced by the topography and structure of the PTFE macrosteps in conjunction with the requirement for a minimal nucleation free energy. The optical absorption of the films in the near infrared is found to be strongly correlated with the structural and morphological modifications in the films. The oriented character of the alpha-TiOPc films results in a strong polarization of the 850-nm band perpendicular to the PTFE chain axis direction.
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页码:904 / 914
页数:11
相关论文
共 43 条
  • [1] Highly ordered vacuum-deposited thin films of metallophthalocyanines and their applications in field-effect transistors
    Bao, ZN
    Lovinger, AJ
    Dodabalapur, A
    [J]. ADVANCED MATERIALS, 1997, 9 (01) : 42 - &
  • [2] GROWTH OF CONJUGATED OLIGOMER THIN-FILMS STUDIED BY ATOMIC-FORCE MICROSCOPY
    BISCARINI, F
    ZAMBONI, R
    SAMORI, P
    OSTOJA, P
    TALIANI, C
    [J]. PHYSICAL REVIEW B, 1995, 52 (20): : 14868 - 14877
  • [3] Phthalocyanine-based field-effect transistor as ozone sensor
    Bouvet, M
    Guillaud, G
    Leroy, A
    Maillard, A
    Spirkovitch, S
    Tournilhac, FG
    [J]. SENSORS AND ACTUATORS B-CHEMICAL, 2001, 73 (01) : 63 - 70
  • [4] Correlation between molecular packing and optical properties in different crystalline polymorphs and amorphous thin films of mer-tris(8-hydroxyquinoline)aluminum(III)
    Brinkmann, M
    Gadret, G
    Muccini, M
    Taliani, C
    Masciocchi, N
    Sironi, A
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (21) : 5147 - 5157
  • [5] HETEROGENEOUS NUCLEATION AT MACROSCOPIC STEPS
    SCHADLER, HW
    [J]. ACTA METALLURGICA, 1964, 12 (08): : 861 - &
  • [6] Oriented growth of n-alkanes crystals on nanostructured poly(tetrafluoroethylene) substrates
    Damman, P
    Fischer, C
    Krüger, JK
    [J]. JOURNAL OF CHEMICAL PHYSICS, 2001, 114 (18) : 8196 - 8204
  • [7] Nucleation and oriented growth of aromatic crystals on friction-transferred poly(tetrafluoroethylene) layers
    Damman, P
    Dosiere, M
    Brunel, M
    Wittmann, JC
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1997, 119 (20) : 4633 - 4639
  • [8] DINI D, 2001, IN PRESS EUR J ORG C
  • [9] Epitaxial and graphoepitaxial growth of materials on highly orientated PTFE substrates
    Fenwick, D
    Smith, P
    Wittmann, JC
    [J]. JOURNAL OF MATERIALS SCIENCE, 1996, 31 (01) : 128 - 131
  • [10] Electroluminescence in conjugated polymers
    Friend, RH
    Gymer, RW
    Holmes, AB
    Burroughes, JH
    Marks, RN
    Taliani, C
    Bradley, DDC
    Dos Santos, DA
    Brédas, JL
    Lögdlund, M
    Salaneck, WR
    [J]. NATURE, 1999, 397 (6715) : 121 - 128