Molecular dynamics simulation of molecular orientation transformation of pentacene on a-SiO2

The molecular orientation has a great impact on the performance of organic thin film transistors (OTFTs) and undesired orientation also appears. There is a critical size nc of the orientation transformation from lateral to normal for pentacene (5A) on the a-SiO2 surface during the vapor-phase deposition process. Molecular dynamics (MD) simulations are performed to get the critical size and gain insight into the transformation mechanism. The results suggest that the delicate interplay between the interaction of molecule-molecule and the interaction of molecule-substrate appears to govern the growth and morphology of pentacene. When n<;nc, the 5A molecules prefer to form lateral oriented cluster with (1-10) surface parallel to the substrate driven by the interaction of molecule-substrate. For n>nc the normal orientation with (001) surface parallel to the substrate becomes stable because the interaction of molecule-molecule holds the dominant position. And a competitive factor Δ between the interaction of molecule-molecule and the interaction of molecule-substrate is established to characterize the results.

[1]  J. Sadowski,et al.  Real‐Time Microscopy of Reorientation Driven Nucleation and Growth in Pentacene Thin Films on Silicon Dioxide , 2013 .

[2]  C. Teichert,et al.  Nucleation and growth of thin films of rod-like conjugated molecules , 2013, Journal of physics. Condensed matter : an Institute of Physics journal.

[3]  Yongfu Zhu,et al.  Molecular orientation transformation in initial growth stage of disk-like phthalocyanine during organic vapor deposition process , 2012 .

[4]  C. Zannoni,et al.  Simulation of Vapor‐Phase Deposition and Growth of a Pentacene Thin Film on C60 (001) , 2011, Advanced materials.

[5]  C. Teichert,et al.  Epitaxially Grown Films of Standing and Lying Pentacene Molecules on Cu(110) Surfaces , 2011, Crystal growth & design.

[6]  C. Ambrosch-Draxl,et al.  Initial stages of a para-hexaphenyl film growth on amorphous mica , 2011 .

[7]  Yoshio Saito,et al.  Polymorphism in pentacene thin films on SiO2 substrate , 2007 .

[8]  Barbara Stadlober,et al.  Growth model of pentacene on inorganic and organic dielectrics based on scaling and rate-equation theory , 2006 .

[9]  P. Clancy,et al.  A Computational Study of the Sub‐monolayer Growth of Pentacene , 2006 .

[10]  A. Sassella,et al.  Incommensurate Epitaxy of Tetrathiophene on Potassium Hydrogen Phthalate: Insights from Molecular Simulation , 2006 .

[11]  T. Ohta,et al.  In-situ measurement of molecular orientation of the pentacene ultrathin films grown on SiO2 substrates , 2006 .

[12]  James R Engstrom,et al.  Nucleation of pentacene on silicon dioxide at hyperthermal energies , 2005 .

[13]  S. T. Lee,et al.  Molecular orientation and film morphology of pentacene on native silicon oxide surface. , 2005, The journal of physical chemistry. B.

[14]  S. Iannotta,et al.  Pentacene Thin Film Growth , 2004 .

[15]  A. Kubono,et al.  Orientational Mechanism for Long-Chain Organic Molecules During Physical Vapor Deposition , 2002 .

[16]  C. C. Mattheus,et al.  Polymorphism in pentacene. , 2001, Acta crystallographica. Section C, Crystal structure communications.

[17]  R. M. Tromp,et al.  Growth dynamics of pentacene thin films , 2001, Nature.