Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 89: Metal substrates: Adsorption of organic / bio molecules V
O 89.9: Talk
Friday, March 30, 2012, 12:30–12:45, A 053
Evaluation of Degree of Charge Transfer in Classical and Novel Donor-Acceptor Complexes Based on Tetracyanoquinodimethane by HAXPES — •Katerina Medjanik1, Andrei Gloskovskii2, Dmytro Kutnyakhov1, Claudia Felser2,3, Jean-Paul Pouget4, Dennis Chercka5, Martin Baumgarten5, Klaus Müllen5, and Gerd Schönhense1 — 1Inst. für Physik, Univ. Mainz — 2Inst. für Anorg. und Anal. Chemie , Univ. Mainz — 3MPI für Chemische Physik fester Stoffe, Dresden — 4Université Paris-Sud, Orsay, France — 5MPI für Polymerforschung, Mainz
Combination of the classical acceptor tetracyanoquinodimethane (TCNQ) with novel donors tetra- and hexamethoxyprene (TMP and HMP) can clarify the question about the nature and degree of charge transfer (CT) and give us the possibility to compare the results with measurements and the same conditions for the prototype system TTF-TCNQ. Hard X-ray photoemission (HAXPES) experiment has been performed at PETRA III (beamline P09) on microcrystals and thin films of HMP/TMP-TCNQ. Upon complex formation, we observed a change of the O1s and N1s spectra from a single-line spectrum to a spectrum with two distinct lines shifted by up to 2.6 eV with respect to the position of the line of the pure donors and acceptors. Peak-area analysis reveals a degree of CT of about 0.6e. This value lies close to the CT of 2/3 for TTF-TCNQ estimated by analysis of the sulphur 2p spectra and for similar CT compounds such as NMP-TCNQ [1].
Funding DFG/TR49, Graduate School MAINZ, COMATT.
[1] J. P. Pouget et al., Phys. Rev. B 21 (1980) 486.