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Competition of Dexter, Förster, and charge transfer pathways for quantum dot sensitized triplet generation.
Metadata
Journaljournal of chemical physics2.991Date
2020-Jun-07
Publication Type
Journal Article
Volume
2020-Jun-07 / 152 : 214702
Author
Jin T 1, Uhlikova N 1, Xu Z 1, Zhu Y 2, Huang Y 2, Egap E 2, Lian T 1
Affiliation
  • 2. Department of Materials Science and NanoEngineering, Rice University, 6100 Main St., Houston, Texas 77005, USA.
Doi
PMIDMESH
Abstract
Quantum dot (QD) sensitized triplet exciton generation has demonstrated promising applications in various fields such as photon up-conversion through triplet-triplet annihilation. However, how direct triplet energy transfer from the QD to the acceptor through Dexter energy transfer (DET) competes with other processes, including Förster resonance energy transfer (FRET) and charge transfer, remains poorly understood. Herein, the competition of these pathways for QD-sensitized triplet excited state generation in CdSe QD-modified boron dipyrromethene (BODIPY) complexes is studied using transient absorption spectroscopy. After excitation of the CdSe QD with 500 nm pulses, the BODIPY triplet excited state is generated through charge recombination in a charge separated intermediate state (QD-·-BODIPY+·). This intermediate state is populated either through FRET from the excited QD to BODIPY followed by electron transfer from the singlet excited state of BODIPY to the QD or through hole transfer from the excited QD to BODIPY. The triplet excited state generation efficiencies from the FRET and hole transfer pathways are estimated to be (6.18 ± 1.39)% and (13.5 ± 3.1)%, respectively. Compared to these indirect pathways, direct DET from the QD to the BODIPY triplet state is kinetically not competitive. These results demonstrate that sequential charge transfer can be an efficient pathway for triplet excited state generation in QD-acceptor complexes.
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J Chem Physjournal of chemical physics
Metadata
LocationUnited States
FromAMER INST PHYSICS

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