Ordered Growth of Substituted Phthalocyanine Thin Films:  Hexadecafluorophthalocyaninatozinc on Alkali Halide (100) and Microstructured Si Surfaces

Abstract

Physical vapor deposition of hexadecafluorophthalocyaninatozinc (F 16 PcZn) is performed under UHV conditions from monolayer coverages to an average thickness of about 20 nm on the (100) surfaces of NaCl, KCl, and KBr and on quartz glass as well as on microstructured interdigitated electrode arrays on amorphous SiO 2 . UV-vis absorption spectroscopy indicates stacks of cofacial parallel molecules for thin films on SiO 2 and NaCl, whereas a component typical for a head-to-tail arrangement of molecules is detected on KCl and KBr. Atomic force microscopy shows well-defined crystals oriented in a defined azimuth angle relative to the substrate lattice on KCl and KBr, indicating a growth in molecular square lattices parallel to the substrate surface which is confirmed by molecular mechanics and periodic surface potential calculations. Plateaus of molecules predominantly standing upright on the surface are seen for the films on NaCl and SiO 2 which is confirmed by the relative intensity of optical absorptions and by the electrical conductivity changes observed during growth on SiO 2 . The temperature dependence of the electrical conductivity of films on SiO 2 yields an increase of the thermal activation energy around 200 °C corresponding to a loss in spectral fine structure as reported earlier [J. Phys. Chem. B 1999, 103, 3078]. A clear correlation is seen between film structure and electrical as well as optical properties of molecular semiconductor thin films.

Spectral characterization of thin films of vanadyl hexadecafluorophthalocyanine VOPcF16

“…7. Such an arrangement of molecules has also been reported for thin films of ZnPcF 16 on quartz [11] and CuPcF 16 on SiO 2 /Si leading to rather high field-effect mobility of charge carriers [1]. The annealing induces thermal reorganization of the film structure, causing the changes of the vibrational spectra.…”

“…Thin films of CuPcF 16 were also characterised by X-ray diffraction and the influence of film disorder on the electron transport properties was investigated [8]. The influence of such factors as temperature and substrate material on structural features of ZnPcF 16 and CuPcF 16 films were also studied [9][10][11][12].…”

Thin Films of Unsubstituted and Fluorinated Palladium Phthalocyanines: Structure and Sensor Response toward Ammonia and Hydrogen

“…Similar spectrum containing the higher energy peak at 613nm and the lower energy peak at 667 nm has been obtained by Jafari et al [8] In contrast to PdPc, the film of PdPcF 16 exhibits a Q-band with one maximum at 643 nm. Such a spectrum with unsplitted Q band was observed only for ultrathin (0.7-1 nm) ZnPcF 16 films deposited on quartz glass and points toward a cofacial parallel arrangement of chromophores [32,33]. Thicker films of MPcF 16 (M=Cu(II), Co(II), Zn(II)) usually exhibits absorption bands located at about 650 and 770 nm [14,20,[33][34][35], where the lower energy absorption band shows a maximum in intensity.…”

Growth and characterization of thin films prepared from perfluoro-isopropyl-substituted perfluorophthalocyanines

“…metal, inorganic oxide insulator, organic polymer insulator) as well as the evaporation conditions [6][7][8][9][10][11][12][13][14]. Fluorination can alter not only the crystal structure but also the growth mode of thin films prepared from fluorinated phthalocyanines [13][14][15][16]. Thus, it is notable that, prior to our work, with the exception of a monochlorinated Pc [17] no single-crystal X-ray structure of ring-halogenated PcM could be found in the Cambridge Structural Database [18] despite the fact that many halogenated phthalocyanines were reported [2,19].…”