Magnetic field dependence of the recombination times in CdSe/CdMnS core/shell nanaoplatelets

We have performed time resolved photoluminescence (PL) studies of colloidal nanoplatelets (NPL) at T = 5 K in the presence of a magnetic field B.  The NPLs consist of a CdSe core surrounded by a CdMnS shell.  The PL has one component  associated with exciton recombination (channel 1) and another with the recombination of electrons with holes localized at the CdSe/CdMnS interfaces (channel 2) [1].   The band edge emission time evolution is described by two time constants.  A shorter time τ₁ associated with channel 1 which does not depend on B and  a longer time τ₂  associated with channel 2.  The time τ₂ for the  σ+  (σ- ) component increases (decreases) with magnetic field.  Furthermore, we observe the B dependence of the two slow times gets smaller at T = 10 K compared to T = 5 K. We have developed a model to interpret these results. [1] J.R. Murphy et al., Appl. Phys. Lett. 2016, 108, 242406