Mechanism of Efficient Viologen Radical Generation by Ultrafast Electron Transfer from CdS Quantum Dots
| Autor: | Ke-Li Han, Tianquan Lian, Feng-Jiao Zhao, Qiuyang Li |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Quantum yield Viologen Electron donor 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Redox 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Electron transfer chemistry.chemical_compound General Energy Nanocrystal chemistry Quantum dot Ultrafast laser spectroscopy medicine Physical and Theoretical Chemistry 0210 nano-technology medicine.drug |
| Zdroj: | The Journal of Physical Chemistry C. 122:17136-17142 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/acs.jpcc.8b06551 |
| Popis: | Artificial photosynthetic systems consisted of nanocrystal light absorbers, molecular redox mediators, and catalysts are one of the most promising and flexible approaches for solar fuel generation because their constituents can be independently tuned. In this work, we investigate the photoreduction of three viologen derivatives, one of the most widely investigated molecular redox mediators, of different redox potentials, 7,8-dihydro-6H-dipyrido[1,2-a:2′,1′-c][1,4]diazepinediium (PDQ2+), methyl viologen (MV2+), and benzyl viologen (BV2+), using CdS quantum dots (QDs) as the light absorber and mercaptopropionic acid as a sacrificial electron donor in aqueous (pH = 7) solution. Under continuous 405 nm light-emitting diode illumination, the steady-state radical generation quantum yield (QY) follows the order of PDQ•+ (15.99%) > MV•+ (12.61%) > BV•+ (6.56%). Transient absorption spectroscopy studies show that while the rates of initial electron transfer (ET) from the excited QD conduction band to the mediators... |
| Databáze: | OpenAIRE |
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