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- Dong, Lin, et al.
(författare)
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Photoluminescence from quasi-type-II spherical CdSe-CdS core-shell quantum dots
- 2013
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 52:1, s. 105-109
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Tidskriftsartikel (refereegranskat)abstract
- Spherical CdSe-CdS core-shell quantum dots (QDs) are found to be flexible in the transition between the type-I regime and the type-II regime with different core/shell dimensions. The quasi-type-II feature of the colloidal dots is confirmed with time-resolved photoluminescence (PL) measurements. Two recombination paths of the excitons with significantly different decay rates are observed and analyzed. The spherical CdSe-CdS core-shell QDs are numerically simulated to investigate the carrier separation. A relatively long radiative lifetime and high degree of spatial carrier separation provide good potential to achieve lasing under continuous-wave excitation. Amplified spontaneous emission at room temperature is detected from the QDs embedded in the polymer matrix. It is shown that a larger shell thickness results in a lower pumping threshold, while a smaller shell thickness leads to higher PL efficiency.
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