Exciton Dynamics in Mn/Ni Dual-doped Semiconductor Quantum Dots
Exciton Dynamics in Mn/Ni Dual-doped Semiconductor Quantum Dots
Doping transition metal impurities in semiconductor quantum dots (QDs) has been shown to offer an effective handle over their electronic, optical and magnetic properties. Incorporation of more than one type of transition ions in same QDs is nontrivial due to different thermodynamic constraints, however, it can provide attractive properties and insights to meet recent challenges in the field of luminescent and magnetic materials. Herein, we present a solution-processed controlled synthesis of Mn and Ni codoped CdS colloidal QDs which show dual emission due to two different impurities. Controlled doping helps to understand the decay dynamics of exciton through various decay channels. Based on the competition between Mn and Ni dopant states, we observe reliable signatures for the short-lived transient charge transfer of the photogenerated hole to the excited state of Mn and then to the Ni state. Along with the interesting excitonic dynamics, we also observe significant enhancement of magnetization due to the codoping.
