Time resolved resonant photoemission study of energy level alignment at donor/acceptor interfaces
Résumé
The knowledge of the picosecond dynamics of the energy level alignment between donor and acceptor materials in organic photovoltaic devices under working conditions is a challenge for fundamental material research. We measured by means of time-resolved Resonant X-ray Photoemission Spectroscopy (RPES) the energy level alignment in ZnPc/C60 films. We employed 800 nm femtosecond laser pulses to pump the system simulating sunlight excitation and X-rays from the synchrotron as a probe. We measured changes in the valence bands due to pump induced modifications of the interface dipole. Our measurements prove the feasibility of time-resolved RPES with high repetition rate sources.
Mots clés
- Ultrashort pulses
- Alignment
- Laser excitation
- Laser pulses
- Optical pumping
- Photoelectron spectroscopy
- Pumping (laser)
- Ultrafast lasers
- X ray photoemission spectroscopy
- Resonant photoemission
- Picosecond dynamics
- Organic photovoltaic devices
- High repetition rate
- Energy level alignment
- Donor/acceptor interface
- Donor and acceptor