Photoluminescence from quasi-type-II spherical CdSe-CdS core-shell quantum dots
2013 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 52, no 1, 105-109 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2013. Vol. 52, no 1, 105-109 p.
Amplified spontaneous emissions, Carrier separation, Colloidal dots, Continuous waves, Core-shell quantum dots, Core/shell, Decay rate, PL efficiency, Pumping threshold, Radiative lifetime, Room temperature, Shell thickness, Time-resolved photoluminescence
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-103439DOI: 10.1364/AO.52.000105ISI: 000313745800061ScopusID: 2-s2.0-84871949571OAI: oai:DiVA.org:kth-103439DiVA: diva2:560159
FunderKnut and Alice Wallenberg Foundation, UAW2004.0224
QC 201302052012-10-122012-10-122013-02-22Bibliographically approved