Detection of shallow electron traps in quantum sized CdS by fluorescence quenching experiments
✍ Scribed by A. Hässelbarth; A. Eychmüller; H. Weller
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 554 KB
- Volume
- 203
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Stationary and time-resolved quenching measurements of the excitonic and trapped fluorescence of quantum sized CdS colloids were carried out. We found that nitromethane is only capable of quenching the excitonic fluorescence nearly completely, whereas a fraction of the trapped fluorescence, the amount of which depends on the particle size, always remains. Methylviologen, with a slightly more positive acceptor potential, is able to quench both types of fluorescence nearly completely in all the investigated samples. The findings are explained straightforwardly by a fluorescence mechanism involving shallow electron traps and deep hole traps located on the surface of the nanocrystailine particles.