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MO: Fachverband Molekülphysik

MO 15: Femtosecond Spectroscopy IV

MO 15.4: Vortrag

Mittwoch, 20. März 2013, 12:00–12:15, F 102

Ultrafast X-ray photoelectron spectroscopy studies of photoinduced electronic dynamics in dye sensitized semiconductor nanocrystals. — •Katrin Siefermann^1,2, Fabian Weise¹, Ming-Fu Lin¹, Camila Bacellar¹, Ali Belkacem¹, Thorsten Weber¹, Felix Sturm¹, Daniel Slaughter¹, Champak Khurmi¹, Travis Wright¹, Bob Schoenlein¹, Matthew Strader¹, Hana Cho¹, Robert Kaindl¹, Giacomo Coslovich¹, David Prendergast¹, Andrey Shavorskiy¹, Hendrik Bluhm¹, Jinghua Guo¹, Marcus Hertlein¹, Tolek Tyliszczak¹, Amy Cordones³, Josh Vura-Weis³, Stephen Leone³, Daniel Neumark³, Sheraz Gul⁴, Jin Zhang⁴, Nils Huse⁵, Martin Beye⁶, Anders Nilsson⁷, Hirohito Ogasawara⁷, Dennis Nordlund⁷, Josh Turner⁷, Bill Schlotter⁷, Oleg Krupin⁷, Michael Holmes⁷, Mike Minitti⁷, Joseph Robinson⁷, Marc Messerschmidt⁷, Phil Heimann⁷, and Oliver Gessner¹ — ¹Lawrence Berkeley National Laboratory, Berkeley, USA — ²Leibniz Institute of Surface Modification, Leipzig, Germany — ³University of California Berkeley, USA — ⁴University of California Santa Cruz, USA — ⁵Center for Free Electron Laser Science, Hamburg, Germany — ⁶Helmholtz Zentrum Berlin, Germany — ⁷SLAC National Accelerator Laboratory, Stanford, USA

We present time-resolved X-ray photoelectron spectroscopy (TRXPS) as a tool to investigate ultrafast dynamics in complex systems in real time. In a proof-of-principle experiment at the Linac Coherent Light Source (LCLS) at SLAC, we monitored the photoinduced oxidation state change of a Ruthenium-based dye complex (N3) attached to zinc oxide nanocrystals. This system is a critical component of dye-sensitized solar cells. In our experiment, an ultrashort laser pulse with a center wavelength of 535 nm electronically excites the Ru dye complex. A time-delayed X-ray pulse centered at ∼850 eV is used to record the inner shell photoelectron spectrum of the sample in the region of the Ru 3d_3/2,5/2 lines. Oxidation of the dye is detected at a pump-probe delay of ∼500 fs as a transient shift of the Ru 3d photoelectron lines by ∼2 eV toward higher binding energies. The experiment represents a first step toward an atomic site specific real-time picture of charge migration in dye sensitized solar cells and demonstrates the potential of time-resolved X-ray photoelectron spectroscopy (TRXPS) as a tool to investigate ultrafast electronic dynamics in complex systems.