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Photoconductance from the Bent-to-Planar Photocycle between Ground and Excited States in Single-Molecule Junctions.
Photoconductance from the Bent-to-Planar Photocycle between Ground and Excited States in Single-Molecule Junctions.
- Source :
-
Journal of the American Chemical Society [J Am Chem Soc] 2022 Jun 08; Vol. 144 (22), pp. 10042-10052. Date of Electronic Publication: 2022 May 25. - Publication Year :
- 2022
-
Abstract
- Single-molecule conductance measurements for 9,14-diphenyl-9,14-dihydrodibenzo[ a , c ]phenazine ( DPAC ) may offer unique insight into the bent-to-planar photocycle between the ground and excited states. Herein, we employ DPAC derivative DPAC-SMe as the molecular prototype to fabricate single-molecule junctions using the scanning tunneling microscope break junction technique and explore photoconductance dependence on the excited-state structural/electronic changes. We find up to ∼200% conductance enhancement of DPAC-SMe under continuous 340 nm light irradiation than that without irradiation, while photoconductance disappears in the case where structural evolution of the DPAC-SMe is halted through macrocyclization. The in situ conductance modulation as pulsed 340 nm light irradiation is monitored in the DPAC-SMe -based junctions alone, suggesting that the photoconductance of DPAC-SMe stems from photoinduced intramolecular planarization. Theoretical calculations reveal that the photoinduced structural evolution brings about a significant redistribution of the electron cloud density, which leads to the appearance of Fano resonance, resulting in enhanced conductance through the DPAC-SMe -fabricated junctions. This work provides evidence of bent-to-planar photocycle-induced conductance differences at the single-molecule level, offering a tailored approach for tuning the charge transport characteristics of organic photoelectronic devices.
- Subjects :
- Electronics
Nanotechnology
Subjects
Details
- Language :
- English
- ISSN :
- 1520-5126
- Volume :
- 144
- Issue :
- 22
- Database :
- MEDLINE
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 35611861
- Full Text :
- https://doi.org/10.1021/jacs.2c03671