Polymorphism and structure formation in copper phthalocyanine thin films

Reisz, Berthold; Belova, Valentina; Duva, Giuliano; Zeiser, Clemens; Hodas, Martin; Hagara, Jakub; Šiffalovič, Peter; Pithan, Linus; Hosokai, Takuya; Hinderhofer, Alexander; Gerlach, Alexander; Schreiber, Frank

doi:10.1107/s1600576720015472

Cited by 10 publications

(6 citation statements)

References 62 publications

(63 reference statements)

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“…3 (a). These findings are in good agreement with previous studies of vacuum deposited CuPc on different substrates [106][107][108][109] . Finally, the reciprocal space map of the blended thin film grown at 400 K exhibits a weak diffraction ring corresponding to the CuPc (100)-reflection, which indicates that the CuPc crystals loose their alignment with the substrate and are now randomly oriented in three dimensions.…”

Section: Experimental Evidence Of Phase Separationsupporting

confidence: 93%

“…Notable is that the substrate temperature increase has a smoothing effect on the CuPc thin film, both in the experiment and in the simulation. Elevating the substrate temperature accelerates the downward diffusion of CuPc molecules and leads to smoother thin films 109 . The columnar growth of elongated CuPc crystals along the substrate supports the smoothing further 109 .…”

Section: A Evolution Of Roughnessmentioning

confidence: 99%

“…Elevating the substrate temperature accelerates the downward diffusion of CuPc molecules and leads to smoother thin films 109 . The columnar growth of elongated CuPc crystals along the substrate supports the smoothing further 109 .…”

Section: A Evolution Of Roughnessmentioning

confidence: 99%

See 2 more Smart Citations

Thin Film Growth of Phase-Separating Phthalocyanine-Fullerene Blends: A Combined Experimental and Computational Study

Reisz,

Empting,

Zwadlo

et al. 2021

Preprint

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Blended organic thin films have been studied during the last decades due to their applicability in organic solar cells. Although their optical and electronic features have been examined intensively, there is still lack of detailed knowledge about their growth processes and resulting morphologies, which play a key role for the efficiency of optoelectronic devices such as organic solar cells. In this study, pure and blended thin films of copper phthalocyanine (CuPc) and the Buckminster fullerene (C60) were grown by vacuum deposition onto a native silicon oxide substrate at two different substrate temperatures, 310 K and 400 K.The evolution of roughness was followed by in-situ real-time X-ray reflectivity. Crystal orientation, island densities and morphology were examined after the growth by X-ray diffraction experiments and microscopy techniques. The formation of a smooth wetting layer followed by rapid roughening was found in pure CuPc thin films, whereas C60 shows a fast formation of distinct islands at a very early stage of growth. The growth of needle-like CuPc crystals loosing their alignment with the substrate was identified in co-deposited thin films. Furthermore, the data demonstrates that structural features become larger and more pronounced and that the island density decreases by a factor of four when going from 310 K to 400 K. Finally, the key parameters roughness and island density were well reproduced on a smaller scale by kinetic Monte-Carlo simulations of a generic, binary lattice model with simple nearestneighbor interaction energies. A weak molecule-substrate interaction caused a fast island formation and a weak interaction between molecules of different species was able to reproduce the observed phase separation. The introduction of different same-species and cross-species Ehrlich-Schwöbel barriers for inter-layer hopping was necessary to reproduce the roughness evolution in the blend and showed the growth of CuPc crystals on top of the thin film in agreement with the experiment.

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Section: Experimental Evidence Of Phase Separationsupporting

confidence: 93%

Section: A Evolution Of Roughnessmentioning

confidence: 99%

See 1 more Smart Citation

Thin Film Growth of Phase-Separating Phthalocyanine-Fullerene Blends: A Combined Experimental and Computational Study

Reisz,

Empting,

Zwadlo

et al. 2021

Preprint

Self Cite

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“…The prototypical semiconducting molecules 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) and copper(II) phthalocyanine (CuPc) (see Figure ) have garnered great interest in the fields of physical chemistry and materials science. Because of their optical and photovoltaic properties, these molecules have potential in a variety of electronic applications, such as organic field-effect transistors, light-emitting diodes, solar cells, and molecular switches. − Extensive studies have been completed on the morphology of these molecules on various kind of substrates, including noble metals, graphene, and insulating substrates. − The molecular arrangement and adsorption to the substrate is of particular interest when stable low-energy configurations are studied. The ability to predict the geometries and the respective energies of these organic semiconducting molecules is critical to the manufacturing of devices and photovoltaics, which emphasize lightweight and low-cost bulk materials. , …”

Section: Introductionmentioning

confidence: 99%

Combined DFT and Molecular Mechanics Modeling of the Adsorption of Semiconducting Molecules on an Ionic Substrate: PTCDA and CuPc on NaCl

Thorpe

Riemann

2022

ACS Omega

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Experimental results suggest that molecular geometry and energies can be influenced by the presence of thin film substrates as well as surrounding molecules. It is imperative that computational models take this influence into account. The accurate computational modeling of these molecules is an efficient way of carrying out chemistry calculations and reinforcing experimental findings. In our study, density functional theory (DFT) and molecular mechanics (MM) are used to model the configurations of the organic semiconducting materials, 3,4,9,10-perylene tetracarboxylic dianhydride, C24H8O6 (PTCDA), and copper(II) phthalocyanine, C32H16CuN8 (CuPc), as adsorbed on single- and double-layer NaCl substrates of various dimensions and charge settings. After a geometry and charge optimization of the molecules using DFT, the molecular geometries are optimized under different environments using computational calculations with specific force-field settings in HyperChem Professional 8.0(TM) software using MM. Energies and geometries of the molecules are then recorded, and our data are compared to experimental results of similar systems. We find that, with the appropriate choice of substrate properties, the calculated molecular configurations directly reflect those found experimentally. Our results support the idea that this method of simulation can produce reliable models in the field of physical chemistry.

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“…Crystal structure identification of both thin organic and inorganic films, especially two-dimensional (2D) materials beyond graphene, attracts considerable interest, amongst others, in potential electronic applications and pharmaceutical science [1][2][3][4][5][6][7][8][9][10]. The presence of a single crystalline substrate surface during the crystallization process can induce new types of molecular or atomic packing because the substrate tends to act as a template for the crystallization process.…”

Section: Introductionmentioning

confidence: 99%

Automatic indexing of two-dimensional patterns in reciprocal space

et al. 2021

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An indispensable part of the structure determination of crystalline two-dimensional (2D) materials and epitaxial thin films is the correct indexing of the acquired diffraction patterns. In our previous work, we described an effective algorithm to determine the 3D unit-cell parameters of complex systems comprising different orientations and polymorphs. In this work, we adapt the indexing method to 2D lattices in reciprocal space. Analyzing low-energy electron diffraction and Fourier-transformed scanning tunneling microscopy measurements, the method is exemplarily applied to thin films of conjugated molecules like 3,4:9,10-perylenetetracarboxylic dianhydride (PTCDA), 6,13-pentacenequinone (P2O), and vanadyl phthalocyanine (VOPc) grown by physical vapor deposition on Ag(111). In all cases unit cells (rhomboids) along with their sixfold rotationally or mirror symmetric counterparts are determined. The already known commensurate epitaxial relationship is reproduced for PTCDA on Ag(111), demonstrating the validity of our method. In the case of P2O/Ag(111) a point-on-line epitaxial condition is found. Our algorithm can be equally well applied to all kinds of 2D patterns in reciprocal space where a crystallographic indexing is required, e.g., electron diffraction data [such as transmission electron diffraction, selected area electron diffraction (SAED)] and fast Fourier transforms (FFTs) of scanning probe images. To demonstrate this aspect, we evaluate FFTs of scanning tunneling microscopy data for stacked VOPc/PTCDA heteroepitaxial layers on Ag(111) as well as SAED data of an epitaxial TiO 2 /LaAlO 3 (100) heterostructure in cross section.

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Polymorphism and structure formation in copper phthalocyanine thin films

Cited by 10 publications

References 62 publications

Thin Film Growth of Phase-Separating Phthalocyanine-Fullerene Blends: A Combined Experimental and Computational Study

Thin Film Growth of Phase-Separating Phthalocyanine-Fullerene Blends: A Combined Experimental and Computational Study

Combined DFT and Molecular Mechanics Modeling of the Adsorption of Semiconducting Molecules on an Ionic Substrate: PTCDA and CuPc on NaCl

Automatic indexing of two-dimensional patterns in reciprocal space

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