Viewing Optical Processes at the Nanoscale: Combining Scanning Tunneling Microscopy and Optical Spectroscopy

Nienhaus, Lea

doi:10.1021/acs.jpcc.2c08912

Cited by 4 publications

(4 citation statements)

References 73 publications

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“…Additionally, the superoptical resolution imaging method has not been applied to dye/NC systems to pinpoint energy transfer events with nanometer spatial resolution. We note that scanning tunneling microscopy and superoptical resolution imaging of nanocrystal emission have been used to image energy flow in nanocrystal solids, , but they have not been applied to nanocrystal/molecule systems under solution phase or photocatalytic conditions. In this work, we develop a single molecule, single NC-level imaging methodology to study defect-mediated EnT between semiconductor NCs and molecular dyes.…”

Section: Introductionmentioning

confidence: 99%

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Toward Imaging Defect-Mediated Energy Transfer between Single Nanocrystal Donors and Single Molecule Acceptors

Lustig

Nilsson

Mulvey

et al. 2023

Chemical & Biomedical Imaging

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Defect-mediated energy transfer is an energy transfer process between midgap electronic states in a semiconductor nanocrystal (NC) and molecular acceptors, such as fluorescent dye molecules. Super-resolution fluorescence microscopy represents an exciting technique for pinpointing the nanoscale positions of lattice defect sites in, for example, a micrometer-sized particle or thin film sample by spatially resolving the location of the acceptor dye molecules with nanometer resolution. Toward this goal, our group performed ensemble-level, time-resolved fluorescence spectroscopy measurements of ZnO NC/Alexafluor 555 (A555) mixtures and calculated that the emissive defect sites are located, on average, 0.5 nm from the NC surface [NilssonZ. N. Nilsson, Z. N. J. Chem. Phys.2021154054704]. However, ensemble-level measurements cannot spatially resolve the defect sites on single particles, nor can they distinguish between surface-adsorbed dye molecules that participate in the energy transfer (EnT) process from those that do not. In this work, we compared the photoluminescence intensity trajectories of 789 isolated, single ZnO NC donors to those of 73 non-specifically bound and five specifically bound ZnO NC/A555 pairs, where the donor and acceptor centroid positions were separated by a distance that was smaller than our localization precision (40 nm). We observed minor fluorescence intensity fluctuations in the donor and defect channels instead of clear anticorrelated intensity fluctuations, which could be explained by (1) the presence of multiple emissive defect sites per NC, (2) donor–acceptor separation distances slightly larger than the Förster radius (R 0 = 3.1 nm; defined as the distance at which EnT is 50% efficient), and/or (3) poor dipole–dipole coupling. The single molecule imaging methodology we developed, an alternating ultraviolet–visible excitation sequence combined with multicolor photon detection, successfully distinguishes specifically bound and non-specifically bound NC/dye pairs and can be applied to study a wide range of hybrid NC/dye energy transfer systems.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Toward Imaging Defect-Mediated Energy Transfer between Single Nanocrystal Donors and Single Molecule Acceptors

Lustig

Nilsson

Mulvey

et al. 2023

Chemical & Biomedical Imaging

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show abstract

“…30 Neinhaus and co-workers provided their perspective on the promise that scanning tunneling microscopy coupled to optical spectroscopy holds for single-molecule detection as well as understanding light-matter interactions on the nanoscale. 31 McNamee et al show that the development of two-pulse action spectroscopies (diagram in Figure 2b), especially with lower cost picosecond diode lasers, allows for measurements of nanosecond-scale energy transport in perovskite layered films and photovoltaic cells. 32 As illustrated by Sun et al, timeresolved photoluminescence studies of charge carrier transport in lead halide perovskites can uncover the carrier dynamics of realistic devices that are typically complex in structure.…”

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confidence: 99%

“…Gross et al gave an extensive review of the different techniques for transient absorption imaging . Neinhaus and co-workers provided their perspective on the promise that scanning tunneling microscopy coupled to optical spectroscopy holds for single-molecule detection as well as understanding light-matter interactions on the nanoscale . McNamee et al show that the development of two-pulse action spectroscopies (diagram in Figure b), especially with lower cost picosecond diode lasers, allows for measurements of nanosecond-scale energy transport in perovskite layered films and photovoltaic cells .…”

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confidence: 99%