Fedorov, A.

Grüneis, A.

Nefedov, A.

Sezen, H.

Verbitskiy, N.

Woell, C.

Zhang, W.

KITopen

Adsorption of Pentacene on Epitaxial Graphene and BN A. Nefedov 1, W. Zhang1,2, H. Sezen1, A. Fedorov3, N. Verbitskiy4, Alexander Grüneis3,4 and C. Wöll1 1 Karlsruhe Institute of Technology, Germany 2 National Synchrotron Radiation Laboratory, Hefei, China 3IFW, Dresden, Germany   4University of Vienna, Vienna, Austria DPG Spring Meeting 2014, Dresden 2 03.04.2014 Dr. Alexei Nefedov Motivation • Pentacene and graphene are promice candidates for organic electronics:   – behaviour on the interface between them is very important  – flat orientation of the first pentacene layer is necessary • Fundamental understanding of the interaction on graphene/metal interface:   – „weak“ or „strong“ (Gaede PrizeTalk of Yu. Dedkov)  Pentacene as a probe molecule  Comparison of EG/Ni(111) vs. EG/Au/Ni(111) and h-BN/Au/Ni(111) • Possible interaction of pentacene with metal substrate through graphene - ? Presence of „surface phase“ similar to chemisorbed pentacene on Ag(111) [Käfer et al, CPL, 442 (2007) 376–383] • Additional challenge:  Evaluation of C K-edge NEXAFS spectra for organic/graphene systems DPG Spring Meeting 2014, Dresden 3 03.04.2014 XPS/NEXAFS endstation @ HESGM (BESSY II) Dr. Alexei Nefedov DPG Spring Meeting 2014, Dresden 4 03.04.2014 Sample preparation and layout of the experiment Dr. Alexei Nefedov Sputtering, Annealing at 600°C Characterization: LEED, XPS Ni(111) CVD from C3H6 /Borazine Characterization: LEED; XPS Ni(111) Au intercalation between graphene and Ni, Control: XPS Quasi-freestanding Graphene/BN Ni(111) Graphene or BN Au Pn deposition Characterization: XPS, NEXAFS Ni(111) Pn Graphene or BN Used systems: EG/Ni(111), EG/Au/Ni(111) and h-BN/Au/Ni(111)  Pn thickness calibration with QCM DPG Spring Meeting 2014, Dresden 5 03.04.2014 XPS: Shift of C1s line after Au intercallation  Dr. Alexei Nefedov 290 288 286 284 282 2800,05,0x1061,0x1071,5x1072,0x107 Binding Energy, eV EG/Ni(111) EG/Au/Ni(111)C1sDPG Spring Meeting 2014, Dresden 6 03.04.2014 NEXAFS: Comparison of EG/Ni and EG/Au/Ni Dr. Alexei Nefedov „Strong“ „Weak“ DPG Spring Meeting 2014, Dresden 7 03.04.2014 Dr. Alexei Nefedov I( , ) = A{P(1/3)[1 + (1/2)(3cos2  - 1)(3cos2  - 1)] + (1 – P)(1/2)sin2 } DPG Spring Meeting 2014, Dresden 8 03.04.2014 Dr. Alexei Nefedov Simulation of NEXAFS spectra  of Pn molecule (in gas phase) DPG Spring Meeting 2014, Dresden 9 03.04.2014 Dr. Alexei Nefedov Comparison: simulation vs. experiment 270 280 290 300 310 320 330-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.5  Intensity, a.u.Photon energy, eVStoBe simulation FWHM = 0.35  eV before 290.33FWHM = 10 eV   after 300.33Experiment thick coverage55 degreesDPG Spring Meeting 2014, Dresden 10 03.04.2014 Dr. Alexei Nefedov Pentacene on graphene: multilayer a=30°, (022)-phase DPG Spring Meeting 2014, Dresden 11 03.04.2014 Dr. Alexei Nefedov 270 280 290 300 310 320 3300246  20° 90°Intensity, a. u.Photon energy, eVPentacene on h-BN: multilayer a=28° DPG Spring Meeting 2014, Dresden 12 03.04.2014 EG/Ni(111): Submonolayer Broadening – hybridization – „strong“ interaction? Or some additional contribution? DPG Spring Meeting 2014, Dresden 13 03.04.2014 Dr. Alexei Nefedov DPG Spring Meeting 2014, Dresden 14 03.04.2014 Dr. Alexei Nefedov DPG Spring Meeting 2014, Dresden 15 03.04.2014 Dr. Alexei Nefedov 280 282 284 286 288 2900123 (sub)monolayer multilayerPentacene/Graphene/Ni(111)Intensity, a.u.Photon energy, eV =55Correction of Graphene contribution No hybridization – „weak“ interaction! Flat orientation of the first Pn layer! DPG Spring Meeting 2014, Dresden 16 03.04.2014 EG/Au/Ni(111): Submonolayer DPG Spring Meeting 2014, Dresden 17 03.04.2014 Dr. Alexei Nefedov EG/Au/Ni(111): growth of the second layer DPG Spring Meeting 2014, Dresden 18 03.04.2014 Dr. Alexei Nefedov Pentacene on h-BN: (sub)monolayer a=0° 270 280 290 300 310 320 33002468101214 20° 55° 75°Intensity, a. u.Photon energy, eVDPG Spring Meeting 2014, Dresden 19 03.04.2014 Dr. Alexei Nefedov Conclusions 1. Flat orientation of pentacene at submonolayer coverages – independent on substrate configuration 2. Direct growth of tilted phase already for the second layer 3. Weak interaction between pentacene and graphene 4. No „surface phase“ was observed – no interaction with metal substrate through EG layer Thank you for attention! 

Adsorption of pentacene on epitaxial graphene and BN

https://publikationen.bibliothek.kit.edu/230095395/3816530

Adsorption of pentacene on epitaxial graphene and BN

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