10.6084/M9.FIGSHARE.C.6323972.V1
Lei Wang
Lei
Wang
Gaoyuan Yang
Gaoyuan
Yang
Boyu Zhang
Boyu
Zhang
Xin Zhang
Xin
Zhang
Dezheng Liu
Dezheng
Liu
Ying Liang
Ying
Liang
Guijie Liang
Guijie
Liang
Unambiguous spectral characterization on triplet energy transfer from quantum dots mediated by hole transfer competing with other carrier dynamics
Triplet generation by QDs-sensitized molecules emerges great potential in many applications. However, the mechanism of triplet energy transfer (TET) is still fuzzy especially due to complicated energy level alignment of QDs and molecules or trap states in QDs. Here, CdSe QDs and 5-tetracene carboxylic acid (TCA) molecules are selected as the triplet donor and acceptor, respectively, to form a TET system. By tuning the band gap of CdSe, the CdSe-TCA complex is exactly designed to present a Type-II like alignment of relative energetics. Coupling transient absorption and time-resolved fluorescence spectra, all carrier dynamics are distinctly elucidated. Quantitative analysis demonstrates that hole transfer persisting for ~ 2 ps outcompetes all other carrier dynamics such as electron trapping (~100 ps level), charge recombination (~ 5 ns) and so-called “back transfer charge recombination” (~50 ns), and thus leads to a hole-transfer-mediated TET process. The low TET yield (~34.0 %) ascribed to electrons consumption can be further improved if electron trapping and charge recombination are efficiently suppressed. The observation on distinguishable carrier dynamics attributed to legitimate design of energy level alignment facilitates better understanding the TET mechanism from QDs to molecules as well as further development of photoelectronic devices based on such TET systems.
Uncategorized
Optica Publishing Group
2022
2022-12-14
2022-12-14
Collection
10.6084/m9.figshare.c.6323972
CC BY 4.0