TY - JOUR
T1 - Hot electron and hole dynamics in thiol-capped CdSe quantum dots revealed by 2D electronic spectroscopy
AU - Lenngren, Nils
AU - Abdellah, Mohamed A.
AU - Zheng, Kaibo
AU - Al-Marri, Mohammed J.
AU - Zigmantas, Donatas
AU - Žídek, Karel
AU - Pullerits, Tõnu
N1 - Publisher Copyright:
© 2016 the Owner Societies.
PY - 2016
Y1 - 2016
N2 - 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 follow excitations in thiol-capped CdSe QDs with state specificity and high time resolution. We unambiguously identify the lowest state as an optically allowed hole trap, and identify 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 enables us to pinpoint correlations between states and to easily separate relaxation from different starting states. We observe the direct rapid trapping of 1S3/2, 2S3/2, and 1S1/2 holes, and several competing electron relaxation processes from the 1Pe state.
AB - 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 follow excitations in thiol-capped CdSe QDs with state specificity and high time resolution. We unambiguously identify the lowest state as an optically allowed hole trap, and identify 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 enables us to pinpoint correlations between states and to easily separate relaxation from different starting states. We observe the direct rapid trapping of 1S3/2, 2S3/2, and 1S1/2 holes, and several competing electron relaxation processes from the 1Pe state.
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U2 - 10.1039/c6cp04190f
DO - 10.1039/c6cp04190f
M3 - Article
AN - SCOPUS:84988591380
SN - 1463-9076
VL - 18
SP - 26199
EP - 26204
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 37
ER -