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Polymorphism and structure formation in copper phthalocyanine thin films
Author(s) -
Reisz Berthold,
Belova Valentina,
Duva Giuliano,
Zeiser Clemens,
Hodas Martin,
Hagara Jakub,
Šiffalovič Peter,
Pithan Linus,
Hosokai Takuya,
Hinderhofer Alexander,
Gerlach Alexander,
Schreiber Frank
Publication year - 2021
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576720015472
Subject(s) - triclinic crystal system , crystallography , copper , reciprocal lattice , thin film , chemistry , materials science , molecule , diffraction , crystal structure , nanotechnology , optics , physics , organic chemistry
Many polymorphic crystal structures of copper phthalocyanine (CuPc) have been reported over the past few decades, but despite its manifold applicability, the structure of the frequently mentioned α polymorph remained unclear. The base‐centered unit cell (space group C 2/ c ) suggested in 1966 was ruled out in 2003 and was replaced by a primitive triclinic unit cell (space group P 1 ). This study proves unequivocally that both α structures coexist in vacuum‐deposited CuPc thin films on native silicon oxide by reciprocal space mapping using synchrotron radiation in grazing incidence. The unit‐cell parameters and the space group were determined by kinematic scattering theory and provide possible molecular arrangements within the unit cell of the C 2/ c structure by excluded‐volume considerations. In situ X‐ray diffraction experiments and ex situ atomic force microscopy complement the experimental data further and provide insight into the formation of a smooth thin film by a temperature‐driven downward diffusion of CuPc molecules during growth.