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Structural, optical, and electronic characterization of perfluorinated sexithiophene films and mixed films with sexithiophene

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Abstract

We report on the growth and characterization of molecular mixed thin films of α-sexithiophene (6T), a well-known organic p-type semiconductor with high hole mobility, together with its perfluorinated counterpart, the so far rarely studied tetradecafluoro-α-sexithiophene (PF6T). Pure and blended thin films of these two molecules with different mixing ratios were grown on silicon oxide in ultrahigh vacuum by coevaporation. The effect of perfluorination and mixing on crystal structure, morphology, electronic, and optical properties was examined. The evolution of the PF6T crystal structure was followed in situ in real time by X-ray scattering. We found a new thin film structure different from the reported bulk phase with molecules either standing-up or lying-down depending on the growth temperature. The different morphologies of pure films and blends were investigated with atomic force microscopy. The impact of mixing on the core-levels and on the highest occupied molecular orbitals of 6T and PF6T is discussed.

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References

  1. S.R. Forrest: The path to ubiquitous and low-cost organic electronic appliances on plastic. Nature 428, 911 (2004).

    Article  CAS  Google Scholar 

  2. G. Witte and C. Wöll: Growth of aromatic molecules on solid substrates for applications in organic electronics. J. Mater. Res. 19, 1889 (2004).

    Article  CAS  Google Scholar 

  3. A. Dodabalapur, H.E. Katz, L. Torsi, and R.C. Haddon: Organic heterostructure field-effect transistors. Science 269, 1560 (1995).

    Article  CAS  Google Scholar 

  4. W. Steinkopf, R. Leitsmann, and K.H. Hofmann: Study of the thiophene series. LVII About alpha-polythienyls. Justus Liebigs Ann. Chem. 546, 180 (1941).

    Article  CAS  Google Scholar 

  5. Y. Sakamoto, S. Komatsu, and T. Suzuki: Tetradecafluorosexithiophene: The first perfluorinated oligothiophene. J. Am. Chem. Soc. 123, 4643 (2001).

    Article  CAS  Google Scholar 

  6. Y. Sakamoto, S. Komatsu, and T. Suzuki: Properties and crystal structure of perfluoro-α-sexithiophene. Synth. Met. 133, 361 (2003).

    Article  CAS  Google Scholar 

  7. G. Horowitz, B. Bachet, A. Yassar, P. Lang, F. Demanze, J-L. Fave, and F. Garnier: Growth and characterization of sexithiophene single crystals. Chem. Mater. 7, 1337 (1995).

    Article  CAS  Google Scholar 

  8. B. Servet, S. Ries, M. Trotel, P. Alnot, G. Horowitz, and F. Garnier: X-ray determination of the crystal structure and orientation of vacuum evaporated sexithiophene films. Adv. Mater. 5, 461 (1993).

    Article  CAS  Google Scholar 

  9. B. Servet, G. Horowitz, S. Ries, O. Lagorsse, P. Alnot, A. Yassar, F. Deloffre, P. Srivastava, and R. Hajlaoui: Polymorphism and charge transport in vacuum-evaporated sexithiophene films. Chem. Mater. 6, 1809 (1994).

    Article  CAS  Google Scholar 

  10. A. Moser, I. Salzmann, M. Oehzelt, A. Neuhold, H-G. Flesch, J. Ivanco, S. Pop, T. Toader, D.R. Zahn, D-M. Smilgies, and R. Resel: A disordered layered phase in thin films of sexithiophene. Chem. Phys. Lett. 574, 51 (2013).

    Article  CAS  Google Scholar 

  11. C. Lorch, R. Banerjee, C. Frank, J. Dieterle, A. Hinderhofer, A. Gerlach, and F. Schreiber: Growth of competing crystal phases of α-sexithiophene studied by real-time X-ray scattering. J. Phys. Chem. C 119, 819 (2015).

    Article  CAS  Google Scholar 

  12. B. Klett, C. Cocchi, L. Pithan, S. Kowarik, and C. Draxl: Polymorphism in α-sexithiophene crystals: Relative stability and transition path. Phys. Chem. Chem. Phys. 18, 14603 (2016).

    Article  CAS  Google Scholar 

  13. P. Amsalem, J. Niederhausen, A. Wilke, G. Heimel, R. Schlesinger, S. Winkler, A. Vollmer, J.P. Rabe, and N. Koch: Role of charge transfer, dipole–dipole interactions, and electrostatics in Fermi-level pinning at a molecular heterojunction on a metal surface. Phys. Rev. B: Condens. Matter Mater. Phys. 87, 035440 (2013).

    Article  CAS  Google Scholar 

  14. L.M. Blinov, S.P. Palto, G. Ruani, C. Taliani, A.A. Tevosov, S.G. Yudin, and R. Zamboni: Location of charge transfer states in alpha-sexithienyl determined by the electroabsorption technique. Chem. Phys. Lett. 232, 401 (1995).

    Article  CAS  Google Scholar 

  15. C. Taliani and L.M. Blinov: The electronic structure of solid α-sexithiophene. Adv. Mater. 8, 353 (1996).

    Article  CAS  Google Scholar 

  16. S. Duhm, H. Glowatzki, V. Cimpeanu, J. Klankermayer, J.P. Rabe, R.L. Johnson, and N. Koch: Weak charge transfer between an acceptor molecule and metal surfaces enabling organic/metal energy level tuning. J. Phys. Chem. B 110, 21069 (2006).

    Article  CAS  Google Scholar 

  17. J. Niederhausen, P. Amsalem, A. Wilke, R. Schlesinger, S. Winkler, A. Vollmer, J.P. Rabe, and N. Koch: Doping of C60 (sub)monolayers by fermi-level pinning induced electron transfer. Phys. Rev. B: Condens. Matter Mater. Phys. 86, 081411 (2012).

    Article  CAS  Google Scholar 

  18. K. Broch, U. Heinemeyer, A. Hinderhofer, F. Anger, R. Scholz, A. Gerlach, and F. Schreiber: Optical evidence for intermolecular coupling in mixed films of pentacene and perfluoropentacene. Phys. Rev. B: Condens. Matter Mater. Phys. 83, 245307 (2011).

    Article  CAS  Google Scholar 

  19. F. Anger, J.O. Ossó, U. Heinemeyer, K. Broch, R. Scholz, A. Gerlach, and F. Schreiber: Photoluminescence spectroscopy of pure pentacene, perfluoropentacene, and mixed thin films. J. Chem. Phys. 136, 054701 (2012).

    Article  CAS  Google Scholar 

  20. J.L. Cabellos, D.J. Mowbray, E. Goiri, A. El-Sayed, L. Floreano, D.G. de Oteyza, C. Rogero, J.E. Ortega, and A. Rubio: Understanding charge transfer in donor–acceptor/metal systems: A combined theoretical and experimental study. J. Phys. Chem. C 116, 17991 (2012).

    Article  CAS  Google Scholar 

  21. K. Kolata, T. Breuer, G. Witte, and S. Chatterjee: Molecular packing determines singlet exciton fission in organic semiconductors. ACS Nano 8, 7377 (2014).

    Article  CAS  Google Scholar 

  22. Y. Inoue, Y. Sakamoto, T. Suzuki, M. Kobayashi, Y. Gao, and S. Tokito: Organic thin-film transistors with high electron mobility based on perfluoropentacene. Jpn. J. Appl. Phys. 44, 3663 (2005).

    Article  CAS  Google Scholar 

  23. Y. Sakamoto, T. Suzuki, M. Kobayashi, Y. Gao, Y. Inoue, and S. Tokito: Perfluoropentacene and perfluorotetracene: Syntheses, crystal structures, and FET characteristics. Mol. Cryst. Liq. Cryst. 444, 225 (2006).

    Article  CAS  Google Scholar 

  24. A. Hinderhofer, U. Heinemeyer, A. Gerlach, S. Kowarik, R.M.J. Jacobs, Y. Sakamoto, T. Suzuki, and F. Schreiber: Optical properties of pentacene and perfluoropentacene thin films. J. Chem. Phys. 127, 194705 (2007).

    Article  CAS  Google Scholar 

  25. N. Koch, A. Vollmer, S. Duhm, Y. Sakamoto, and T. Suzuki: The effect of fluorination on pentacene/gold interface energetics and charge reorganization energy. Adv. Mater. 19, 112 (2007).

    Article  CAS  Google Scholar 

  26. S. Kowarik, A. Gerlach, A. Hinderhofer, S. Milita, F. Borgatti, F. Zontone, T. Suzuki, F. Biscarini, and F. Schreiber: Structure, morphology, and growth dynamics of perfluoro-pentacene thin films. Phys. Status Solidi RRL 2, 120 (2008).

    Article  CAS  Google Scholar 

  27. I. Salzmann, S. Duhm, G. Heimel, J.P. Rabe, N. Koch, M. Oehzelt, Y. Sakamoto, and T. Suzuki: Structural order in perfluoropentacene thin films and heterostructures with pentacene. Langmuir 24, 7294 (2008).

    Article  CAS  Google Scholar 

  28. I. Salzmann, S. Duhm, G. Heimel, M. Oehzelt, R. Kniprath, R.L. Johnson, J.P. Rabe, and N. Koch: Tuning the ionization energy of organic semiconductor films: The role of intramolecular polar bonds. J. Am. Chem. Soc. 130, 12870 (2008).

    Article  CAS  Google Scholar 

  29. U. Heinemeyer, K. Broch, A. Hinderhofer, M. Kytka, R. Scholz, A. Gerlach, and F. Schreiber: Real-time changes in the optical spectrum of organic semiconducting films and their thickness regimes during growth. Phys. Rev. Lett. 104, 257401 (2010).

    Article  CAS  Google Scholar 

  30. A. Hinderhofer, C. Frank, T. Hosokai, A. Resta, A. Gerlach, and F. Schreiber: Structure and morphology of coevaporated pentacene-perfluoropentacene thin films. J. Chem. Phys. 134, 104702 (2011).

    Article  CAS  Google Scholar 

  31. S. Kera, S. Hosoumi, K. Sato, H. Fukagawa, S-i. Nagamatsu, Y. Sakamoto, T. Suzuki, H. Huang, W. Chen, A.T.S. Wee, V. Coropceanu, and N. Ueno: Experimental reorganization energies of pentacene and perfluoropentacene: Effects of perfluorination. J. Phys. Chem. C 117, 22428 (2013).

    Article  CAS  Google Scholar 

  32. A. El-Sayed, P. Borghetti, E. Goiri, C. Rogero, L. Floreano, G. Lovat, D.J. Mowbray, J.L. Cabellos, Y. Wakayama, A. Rubio, J.E. Ortega, and D.G. de Oteyza: Understanding energy-level alignment in donor–acceptor/metal interfaces from core-level shifts. ACS Nano 7, 6914 (2013).

    Article  CAS  Google Scholar 

  33. K. Broch, C. Bürker, J. Dieterle, S. Krause, A. Gerlach, and F. Schreiber: Impact of molecular tilt angle on the absorption spectra of pentacene:perfluoropentacene blends. Phys. Status Solidi RRL 7, 1084 (2013).

    Article  CAS  Google Scholar 

  34. C. Frank, J. Novák, A. Gerlach, G. Ligorio, K. Broch, A. Hinderhofer, A. Aufderheide, R. Banerjee, R. Nervo, and F. Schreiber: Real-time X-ray scattering studies on temperature dependence of perfluoropentacene thin film growth. J. Appl. Phys. 114, 043515 (2013).

    Article  CAS  Google Scholar 

  35. S-A. Savu, A. Sonström, R. Bula, H.F. Bettinger, T. Chassé, and M.B. Casu: Intercorrelation of electronic, structural, and morphological properties in nanorods of 2,3,9,10-tetrafluoropentacene. ACS Appl. Mater. Interfaces 7, 19774 (2015).

    Article  CAS  Google Scholar 

  36. H-Y. Chen and I. Chao: Effect of perfluorination on the charge transport properties of organic semiconductors: Density functional theory study of perfluorinated pentacene and sexithiophene. Chem. Phys. Lett. 401, 539 (2005).

    Article  CAS  Google Scholar 

  37. B.M. Medina, D. Beljonne, H-J. Egelhaaf, and J. Gierschner: Effect of fluorination on the electronic structure and optical excitations of π-conjugated molecules. J. Chem. Phys. 126, 111101 (2007).

    Article  CAS  Google Scholar 

  38. K. Hamano, T. Kurata, S. Kubota, and H. Koezuka: Organic molecular beam deposition of α-sexithienyl. Jpn. J. Appl. Phys. 33, L1031 (1994).

    Article  CAS  Google Scholar 

  39. S.R. Forrest: Ultrathin organic films grown by organic molecular beam deposition and related techniques. Chem. Rev. 97, 1793 (1997).

    Article  CAS  Google Scholar 

  40. F. Schreiber: Organic molecular beam deposition: Growth studies beyond the first monolayer. Phys. Status Solidi A 201, 1037 (2004).

    Article  CAS  Google Scholar 

  41. A. Hinderhofer and F. Schreiber: Organic–organic heterostructures: Concepts and applications. ChemPhysChem 13, 628 (2012).

    Article  CAS  Google Scholar 

  42. K.A. Ritley, B. Krause, F. Schreiber, and H. Dosch: A portable ultrahigh vacuum organic molecular beam deposition system for in situ X-ray diffraction measurements. Rev. Sci. Instrum. 72, 1453 (2001).

    Article  CAS  Google Scholar 

  43. P.R. Willmott, D. Meister, S.J. Leake, M. Lange, A. Bergamaschi, M. Böge, M. Calvi, C. Cancellieri, N. Casati, A. Cervellino, Q. Chen, C. David, U. Flechsig, F. Gozzo, B. Henrich, S. Jäggi-Spielmann, B. Jakob, I. Kalichava, P. Karvinen, J. Krempasky, A. Lüdeke, R. Lüscher, S. Maag, C. Quitmann, M.L. Reinle-Schmitt, T. Schmidt, B. Schmitt, A. Streun, I. Vartiainen, M. Vitins, X. Wang, and R. Wullschleger: The materials science beamline upgrade at the swiss light source. J. Synchrotron Radiat. 20, 667 (2013).

    Article  CAS  Google Scholar 

  44. Supplementary Material.

  45. D.W. Johnson: A fourier series method for numerical Kramers-Kronig analysis. J. Phys. A: Math. Gen. 8, 490 (1975).

    Article  Google Scholar 

  46. A.I. Beltzer: Kramers–Kronig relationships and wave propagation in composites. J. Acoust. Soc. Am. 73, 355 (1983).

    Article  Google Scholar 

  47. A.O.F. Jones, B. Chattopadhyay, Y.H. Geerts, and R. Resel: Substrate-induced and thin-film phases: Polymorphism of organic materials on surfaces. Adv. Funct. Mater. 26, 2233 (2016).

    Article  CAS  Google Scholar 

  48. C. Ambrosch-Draxl, D. Nabok, P. Puschnig, and C. Meisenbichler: The role of polymorphism in organic thin films: Oligoacenes investigated from first principles. New J. Phys. 11, 125010 (2009).

    Article  CAS  Google Scholar 

  49. C.C. Mattheus, A.B. Dros, J. Baas, A. Meetsma, J.L.d. Boer, and T.T.M. Palstra: Polymorphism in pentacene. Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 57, 939 (2001).

    Article  CAS  Google Scholar 

  50. S. Schiefer, M. Huth, A. Dobrinevski, and B. Nickel: Determination of the crystal structure of substrate-induced pentacene polymorphs in fiber structured thin films. J. Am. Chem. Soc. 129, 10316 (2007).

    Article  CAS  Google Scholar 

  51. S. Kowarik, A. Gerlach, W. Leitenberger, J. Hu, G. Witte, C. Wöll, U. Pietsch, and F. Schreiber: Energy-dispersive X-ray reflectivity and GID for real-time growth studies of pentacene thin films. Thin Solid Films 515, 5606 (2007).

    Article  CAS  Google Scholar 

  52. S. Kowarik, A. Gerlach, S. Sellner, F. Schreiber, L. Cavalcanti, and O. Konovalov: Real-time observation of structural and orientational transitions during growth of organic thin films. Phys. Rev. Lett. 96, 125504 (2006).

    Article  CAS  Google Scholar 

  53. T. Kakudate, N. Yoshimoto, and Y. Saito: Polymorphism in pentacene thin films on SiO2 substrate. Appl. Phys. Lett. 90, 081903 (2007).

    Article  CAS  Google Scholar 

  54. E. Bauer and H. Poppa: Recent advances in epitaxy. Thin Solid Films 12, 167 (1972).

    Article  CAS  Google Scholar 

  55. R.L. Schwoebel and E.J. Shipsey: Step motion on crystal surfaces. J. Appl. Phys. 37, 3682 (1966).

    Article  CAS  Google Scholar 

  56. G. Ehrlich and F.G. Hudda: Atomic view of surface self-diffusion: Tungsten on tungsten. J. Chem. Phys. 44, 1039 (1966).

    Article  CAS  Google Scholar 

  57. Z. Zhang and M. Lagally: Atomistic processes in the early stages of thin-film growth. Science 276, 377 (1997).

    Article  CAS  Google Scholar 

  58. S. Liu and H. Metiu: Inter-layer diffusion and motion of adatoms in the vicinity of steps. Surf. Sci. 359, 245 (1996).

    Article  CAS  Google Scholar 

  59. P.J. Feibelman: Interlayer self-diffusion on stepped Pt(111). Phys. Rev. Lett. 81, 168 (1998).

    Article  CAS  Google Scholar 

  60. P. Feibelman: Ordering of self-diffusion barrier energies on pt (110)-(1 × 2). Phys. Rev. B: Condens. Matter Mater. Phys. 61, R2452 (2000).

    Article  CAS  Google Scholar 

  61. J.A. Venables: Rate equation approaches to thin film nucleation kinetics. Philos. Mag. 27, 697 (1973).

    Article  CAS  Google Scholar 

  62. J.A. Venables, G.D.T. Spiller, and M. Hanbücken: Nucleation and growth of thin films. Rep. Prog. Phys. 47, 399 (1984).

    Article  Google Scholar 

  63. J.A. Venables: Atomic processes in crystal growth. Surf. Sci. 299, 798 (1994).

    Article  Google Scholar 

  64. L.W. Bruch, R.D. Diehl, and J.A. Venables: Progress in the measurement and modeling of physisorbed layers. Rev. Mod. Phys. 79, 1381 (2007).

    Article  CAS  Google Scholar 

  65. J. Villain, A. Pimpinelli, L. Tang, and D. Wolf: Terrace sizes in molecular beam epitaxy. J. Phys. 2, 2107 (1992).

    Google Scholar 

  66. F. Biscarini, P. Samori, O. Greco, and R. Zamboni: Scaling behavior of anisotropic organic thin films grown in high vacuum. Phys. Rev. Lett. 78, 2389 (1997).

    Article  CAS  Google Scholar 

  67. R.N. Marks, F. Biscarini, T. Virgili, M. Muccini, R. Zamboni, and C. Taliani: The growth and characterization of α-sexithienyl-based light-emitting diodes. Philos. Trans. R. Soc., A 355, 763 (1997).

    Article  CAS  Google Scholar 

  68. A. Sassella, M. Campione, L. Raimondo, S. Tavazzi, A. Borghesi, C. Goletti, G. Bussetti, and P. Chiaradia: Epitaxial growth of organic heterostructures: Morphology, structure, and growth mode. Surf. Sci. 601, 2571 (2007).

    Article  CAS  Google Scholar 

  69. B. Quan, S-H. Yu, D.Y. Chung, A. Jin, J.H. Park, Y-E. Sung, and Y. Piao: Single source precursor-based solvothermal synthesis of heteroatom-doped graphene and its energy storage and conversion applications. Sci. Rep. 4, 7 (2014).

    Google Scholar 

  70. D. Oeter, C. Ziegler, and W. Göpel: Doping and stability of ultrapure α-oligothiophene thin films. Synth. Met. 61, 147 (1993).

    Article  CAS  Google Scholar 

  71. W.R. Salaneck, O. Inganäs, B. Thémans, J.O. Nilsson, B. Sjögren, J-E. Österholm, J.L. Brédas, and S. Svensson: Thermochromism in poly(3-hexylthiophene) in the solid state: A spectroscopic study of temperature-dependent conformational defects. J. Chem. Phys. 89, 4613 (1988).

    Article  CAS  Google Scholar 

  72. V. Shrotriya, J. Ouyang, R.J. Tseng, G. Li, and Y. Yang: Absorption spectra modification in poly(3-hexylthiophene): Methanofullerene blend thin films. Chem. Phys. Lett. 411, 138 (2005).

    Article  CAS  Google Scholar 

  73. A. Lachkar, A. Selmani, and E. Sacher: Metallization of polythiophenes II. Interaction of vapor-deposited Cr, V and Ti with poly(3-hexylthiophene) (P3HT). Synth. Met. 72, 73 (1995).

    Article  CAS  Google Scholar 

  74. M. Manceau, J. Gaume, A. Rivaton, J-L. Gardette, G. Monier, and L. Bideux: Further insights into the photodegradation of poly(3-hexylthiophene) by means of X-ray photoelectron spectroscopy. Thin Solid Films 518, 7113 (2010).

    Article  CAS  Google Scholar 

  75. A. Opitz, A. Wilke, P. Amsalem, M. Oehzelt, R-P. Blum, J.P. Rabe, T. Mizokuro, U. Hörmann, R. Hansson, E. Moons, and N. Koch: Organic heterojunctions: Contact-induced molecular reorientation, interface states, and charge re-distribution. Sci. Rep. 6, 21291 (2016).

    Article  CAS  Google Scholar 

  76. H. Yoshida, K. Yamada, J. Tsutsumi, and N. Sato: Complete description of ionization energy and electron affinity in organic solids: Determining contributions from electronic polarization, energy band dispersion, and molecular orientation. Phys. Rev. B: Condens. Matter Mater. Phys. 92, 8 (2015).

    Google Scholar 

  77. D.A.G. Bruggeman: Calculation of various physical constants of heterogeneous substances. I. Dielectric constants and conductivity of solids mixed of isotropic substances. Ann. Phys. 416, 636 (1935).

    Article  Google Scholar 

  78. D.M. Popovic, V. Milosavljevic, A. Zekic, N. Romcevic, and S. Daniels: Raman scattering analysis of silicon dioxide single crystal treated by direct current plasma discharge. Appl. Phys. Lett. 98, 051503 (2011).

    Article  CAS  Google Scholar 

  79. A. Degli Esposti, M. Fanti, M. Muccini, C. Taliani, and G. Ruani: The polarized infrared and Raman spectra of α-T6 single crystal: An experimental and theoretical study. J. Chem. Phys. 112, 5957 (2000).

    Article  CAS  Google Scholar 

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ACKNOWLEDGMENTS

We gratefully acknowledge the financial support of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) and we thank the Paul Scherrer Institute for providing excellent facilities at the material science beam line MS-X04SA of the Swiss Light Source. C.L. and G.D. acknowledge financial support from the Carl-Zeiss-Stiftung. In addition, this research has been partly supported by JSPS KAKENHI (No. 24245034), by Grant-in-Aid for JSPS Research Fellow (15J08155) and by Global COE program (G-03, MEXT).

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Reisz, B., Weimer, S., Banerjee, R. et al. Structural, optical, and electronic characterization of perfluorinated sexithiophene films and mixed films with sexithiophene. Journal of Materials Research 32, 1908–1920 (2017). https://doi.org/10.1557/jmr.2017.99

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