INOR 488 |
| The enhancement of carrier multiplication (CM) is an important aim that could increase solar cell performance and widen the range of materials suitable for future solar technologies. Recent pump-probe measurements have shown evidence of strongly enhanced CM in lead chalcogenide and CdSe nanocrystals (NCs). However, the nature of the enhancement mechanism is not well understood and is the subject of considerable debate. We have carried out a new experimental assessment of CM yields in CdSe and CdTe NCs by carefully analyzing exciton and biexciton signatures in transient photoluminescence decays. Though the technique is particularly sensitive due to the strong biexciton radiative rate, we find no evidence for CM up to photon energies as high as 3.1 Eg. These are well above previously reported relative energy thresholds for CdSe NCs. Implications are discussed within a general physical framework. |
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Nanoscience: Applications
8:30 AM-12:10 PM, Tuesday, August 21, 2007 BCEC -- 209, Oral
Division of Inorganic Chemistry |