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Two new Rh 2 ( ii , ii ) dyes were synthesized and anchored to TiO 2 for charge injection upon irradiation. The 1 ML-LCT (metal/ligand-to-ligand charge transfer) excited state is populated upon excitation, which decays to the corresponding 3 ML-LCT state. Ultrafast electron injection into TiO 2 from the Rh 2 ( ii , ii ) dyes was achieved with low energy, red light excitation.
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Excitation energy-dependent photocurrent switching in a single-molecule photodiode
The direction of electron flow in molecular optoelectronic devices is dictated by charge transfer between a molecular excited state and an underlying conductor or semiconductor. For those devices, controlling the direction and reversibility of electron flow is a major challenge. We describe here a novel, single-molecule photodiode. It is based on an internally conjugated, bi-chromophoric dyad with chemically linked (porphyrinato)zinc(II) and bis(terpyridyl)ruthenium(II) groups. On nanocrystalline, degenerately doped indium tin oxide electrodes, the dyad exhibits distinct frequency-dependent, charge-transfer characters. Variations in the light source between red (~ 1.9 eV) and blue (~ 2.7 eV) light excitation for the integrated photodiode result in switching of photocurrents between cathodic and anodic. The origin of the excitation frequency-dependent photocurrents lies in the electronic structure of the chromophore excited states, as shown by the results of theoretical calculations, laser flash photolysis and steady-state spectrophotometric measurements.
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- Award ID(s):
- 1709497
- PAR ID:
- 10104128
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences of the United States of America
- Volume:
- 116
- Issue:
- 33
- ISSN:
- 0027-8424
- Page Range / eLocation ID:
- 16198-16203
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/https://doi.org/10.1073/pnas.1907118116
