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A combination of picosecond and microsecond transient absorption dynamics reveals the involvement of two mechanisms by which 1,4-benzoquinone (BQ) induces the decay of the excited state of PbS quantum dots (QDs): (i) electron transfer to BQ molecules adsorbed to the surfaces of PbS QDs and (ii) collisionally gated electron transfer to freely diffusing BQ.(More)
Photoinduced hole transfer from PbS quantum dots (QDs) to aminoferrocene only occurs if the ligand shell of the QD allows aminoferrocene to gain direct access to the inorganic core of the QD; the permeability of the ligand shell is therefore more important than its conductivity in determining the probability of interfacial charge transfer.
Gold nanoparticles (ca. 3 nm in diameter) coated with bis(diarylamino)biphenyl-based thiols with two different alkyl spacers (propyl and dodecyl) between the chromophore and the surface-anchoring thiol group have been prepared and characterized with a variety of techniques. The excited-state dynamics of the dyes in close proximity to the nanoparticle(More)
Self-assembled monolayers of E-stilbene-4-thiolate (SAM1), E-4'-(ethoxy)stilbene-4-thiolate (SAM2), and E-4'-(dimethylamino)stilbene-4-thiolate (SAM3) on Au(111) have been obtained from reaction of ethanol solutions of the corresponding S-acetyl derivatives with gold substrates. A combination of X-ray photoelectron spectroscopy, ellipsometry, and infrared(More)
This paper describes an investigation of the interfacial chemistry that enables formation of a multielectron ground-state charge-transfer (CT) complex of oleate-coated PbS quantum dots (QDs) and tetracyanoquinodimethane (TCNQ) in CHCl3 dispersions. Thermodynamically spontaneous electron transfer occurs from sulfur ions on the surfaces of the QDs (radius =(More)
A combination of FT-IR, (1)H NMR, nuclear Overhauser effect (NOESY), and diffusion-ordered (DOSY) NMR spectroscopies shows that samples of oleate-coated PbS quantum dots (QDs) with core radii ranging from 1.6 to 2.4 nm, and purified by washing with acetone, contain two species of oleate characterized by the stretching frequencies of their carboxylate(More)
This paper describes the mechanisms of charge recombination on both the nanosecond and microsecond time scales in a donor-acceptor system comprising thiol-modified bis(diarylamino)4,4'-biphenyl (TPD) molecules attached to a CdS quantum dot (QD) via the thiolate linker. Transient absorption measurements, in conjunction with EPR and magnetic field effect(More)
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