Colloidal quantum dots (QDs) have attracted interest as materials for opto-electronic applications, wherein their efficient energy use requires the understanding of carrier relaxation. In QDs capped by bifunctional thiols, used to attach the QDs to a surface, the relaxation is complicated by carrier traps.
Using 2D spectroscopy at 77 K, we followed excitations in thiol-capped CdSe QDs and identified the lowest state as an optically allowed hole trap as well as determined an electron trap with excited-state absorption. The presence of traps changes the initial dynamics entirely by offering a different relaxation channel. 2D electronic spectroscopy enabled us to pinpoint correlations between states and to separate relaxation from different starting states.
- Pullerits group
- Zigmantas group
- N. Lenngren, M.A. Abdellah, K. Zheng, M.J. Al-Marri, D. Zigmantas, K. Židek, T. Pullerits, Hot electron and hole dynamics in thiol-capped CdSe quantum dots revealed by 2D electronic spectroscopy, Physical Chemistry Chemical Physics, 18, 26199-26204, (2016).
- Department of Chemistry, Qena Faculty of Science, South Valley University, Egypt
- Gas Processing Center, College of Engineering, Qatar University, Qatar
- Regional Centre for Special Optics and Optoelectronic Systems (TOPTEC), Institute of Plasma Physics, Academy of Sciences of the Czech Republic, Czech Republic