Photocurrent detected 2D spectroscopy reveals details of multiple exciton generation in colloidal quantum dots
Event details
| Date | 20.11.2014 |
| Hour | 16:30 › 17:30 |
| Speaker |
Prof. Tõnu Pullerits Chemical Physics, Lund University, Sweden |
| Location | |
| Category | Conferences - Seminars |
Recently there has been growing interest in the role of coherence in electronic dynamics. Coherent multidimensional spectroscopy (CMS) has been used to reveal coherent phenomena in numerous material systems. Here we utilize a recent implementation of CMS – two-dimensional photocurrent spectroscopy (2DPS), in which we detect the photocurrent from a PbS quantum dot (QD) photocell resulting from its interactions with a sequence of four ultrafast laser pulses. We observe sub-picosecond evolution of 2D spectra consistent with multiple exciton generation. Moreover, a comparison to 2D fluorescence spectra of the QDs demonstrates the potential of 2DPS to elucidate the detailed origin of photocurrent generating electronic state coherence pathways. Since the measurement is based on detecting the photocell current in situ, the method is well suited to study fundamental ultrafast processes that affect the function of the device. This opens new avenues for the investigation and implementation of coherent optimization strategies directly within devices.
Practical information
- General public
- Free
Organizer
- Dr Frank van Mourik