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| Publications [#383240] of David N. Beratan
Journal Articles
- Jin, T; Zhang, Z; He, S; Kaledin, AL; Xu, Z; Liu, Y; Zhang, P; Beratan, DN; Lian, T, Shell Thickness and Heterogeneity Dependence of Triplet Energy Transfer between Core-Shell Quantum Dots and Adsorbed Molecules.,
Journal of the American Chemical Society, vol. 147 no. 19
(May, 2025),
pp. 16282-16292 [doi]
(last updated on 2026/01/14)
Abstract:
Quantum dot (QD)-sensitized triplet energy transfer (TET) has found promising applications in photon upconversion and photocatalysis. However, the underlying mechanism of TET in the QD-acceptor complex remains unclear despite the well-developed TET theory for the molecular donor-acceptor systems. Herein, the coupling strength of TET from CdSe/CdS core-shell QDs to 9-anthracene carboxylic acid (ACA) was studied by measuring the TET rate as a function of shell thickness with time-resolved photoluminescence. The change of TET-coupling strength with increasing shell thickness was further compared to those of electron and hole transfers from QDs so that we could test whether QD-sensitized TET is mediated by the charge transfer virtual state and can be considered as simultaneous electron and hole transfers as in molecular donor-acceptor systems. The measured coupling strength of TET from the CdSe/CdS QD decreases exponentially with the CdS shell thickness r: |V|(r) = |V|(0)e-βr, with an exponential decay factor β of 0.19 Å-1, which is smaller than the sum of the measured decay factors for electron transfer to methyl viologen (0.18 Å-1) and hole transfer to phenothiazine (0.29 Å-1) from the same QD. This inconsistency is explained by the broadening of QD shell thicknesses in the distance dependence study, which significantly modifies the TET-coupling strength and driving force, resulting in a shallower distance dependence of the TET rate constants. This study sheds light on the fundamental mechanisms of QD-sensitized TET reactions.
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