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Author Notes:
Corresponding authors: francesco.evangelista@emory.edu; tlian@emory.edu; ee30@rice.edu
There are no conflicts to declare.
Subjects:
Research Funding:
T. L. gratefully acknowledges the financial support from the National Science Foundation (CHE-1709182).
E. A. acknowledges support from the National Science Foundation (CHE-1821863).
F. A. E. acknowledges support from the U.S. Department of Energy under Award No. DE-SC0016004, the Camille and Henry Dreyfus Foundation under award TC-18-045, and the Alfred P. Sloan Foundation under award FG_20166748.
Keywords:
- triplet states
- annihilation
- photon upconversion schemes
- sensitization
- CdSe QD-bound oligothiophene carboxylic acid T6
- spectroscopy
- Dexter-type triplet energy transfer
Direct triplet sensitization of oligothiophene by quantum dots
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Abstract:
Effective sensitization of triplet states is essential to many applications, including triplet-triplet annihilation based photon upconversion schemes. This work demonstrates successful triplet sensitization of a CdSe quantum dot (QD)-bound oligothiophene carboxylic acid (T6). Transient absorption spectroscopy provides direct evidence of Dexter-type triplet energy transfer from the QD to the acceptor without populating the singlet excited state or charge transfer intermediates. Analysis of T6 concentration dependent triplet formation kinetics shows that the intrinsic triplet energy transfer rate in 1:1 QD-T6 complexes is 0.077 ns-1 and the apparent transfer rate and efficiency can be improved by increasing the acceptor binding strength. This work demonstrates a new class of triplet acceptor molecules for QD-based upconversion systems that are more stable and tunable than the extensively studied polyacenes.
Copyright information:
© 2019 The Royal Society of Chemistry.
This is an Open Access work distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/).
