CHEM01200604009 Sreejith Kaniyankandy - Homi Bhabha ...

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In addition to the cooling dynamics Figure 8 also shows the bleach recovery
dynamics of core and different core-shells. The bleach recovery kinetics can be fitted multiexponentially
with different time constants with τ 1 = 2.55 ps (45%), τ 2 = 27 ps (17%) and τ 3 =
> 400 ps (38%) for CdSe core, τ 1 = 2.6 ps (30%), τ 2 = 30 ps (33%) and τ 3 = > 400 ps (37%)
for CdSe/ZnTe3 core-shell and τ 1 = 3 ps (21.5%), τ 2 = 50 ps (32.5%) and τ 3 = > 400 ps (46%)
for CdSe/ZnTe4 core-shell. It clearly hints at the multi-exponential nature of bleach recovery
tell us that the charge carrier dynamics is governed by more than one process. The multiexponential
nature of the dynamics can come from multiple sizes QD in addition to trapping
dynamics of trap states. If the dynamics is dominated by only one lifetime contribution it
could come from single dot contribution. However in the present case we have long
component which contributes quite substantially (> 30%). Since under the present excitation
conditions N