Subpicosecond Photoinduced Hole Transfer from a CdS Quantum Dot to a Molecular Acceptor Bound Through an Exciton-Delocalizing Ligand
| Autor: | Mohamad S. Kodaimati, Shichen Lian, Rachel D. Harris, Emily A. Weiss, David J. Weinberg |
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| Rok vydání: | 2016 |
| Předmět: |
Band gap
Exciton General Engineering General Physics and Astronomy 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Acceptor Molecular physics 0104 chemical sciences chemistry.chemical_compound Colloid Delocalized electron chemistry Quantum dot Phenothiazine Proton NMR General Materials Science 0210 nano-technology |
| Zdroj: | ACS Nano. 10:6372-6382 |
| ISSN: | 1936-086X 1936-0851 |
| Popis: | This paper describes the enhancement of the rate of hole transfer from a photoexcited CdS quantum dot (QD), with radius R = 2.0 nm, to a molecular acceptor, phenothiazine (PTZ), by linking the donor and acceptor through a phenyldithiocarbamate (PTC) linker, which is known to lower the confinement energy of the excitonic hole. Upon adsorption of PTC, the bandgap of the QD decreases due to delocalization of the exciton, primarily the excitonic hole, into interfacial states of mixed QD/PTC character. This delocalization enables hole transfer from the QD to PTZ in300 fs (within the instrument response of the laser system) when linked by PTC, but not when linked by a benzoate group, which has a similar length and conjugation as PTC but does not delocalize the excitonic hole. Comparison of the two systems was aided by quantification of the surface coverage of benzoate and PTC-linked PTZ by (1)H NMR. This work provides direct spectroscopic evidence of the enhancement of the rate of hole extraction from a colloidal QD through covalent linkage of a hole acceptor through an exciton-delocalizing ligand. |
| Databáze: | OpenAIRE |
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