Light-Induced Paramagnetism in Colloidal Ag<sup>+</sup>-Doped CdSe Nanoplatelets
Arman Najafi, Manoj Sharma, Savas Delikanli, Arinjoy Bhattacharya, Joseph Murphy, James Pientka, Ashma Sharma, Alexander P. Quinn, Onur Erdem, Subash Kattel, Yusuf Keleştemur, Maksym V. Kovalenko, William Rice, Hilmi Volkan Demir, A. Petrou
Abstract
We describe a study of the magneto-optical properties of Ag+-doped CdSe colloidal nanoplatelets (NPLs) that were grown using a novel doping technique. In this work, we used magnetic circularly polarized luminescence and magnetic circular dichroism spectroscopy to study light-induced magnetism for the first time in 2D solution-processed structures doped with nominally nonmagnetic Ag+ impurities. The excitonic circular polarization (PX) and the exciton Zeeman splitting (ΔEZ) were recorded as a function of the magnetic field (B) and temperature (T). Both ΔEZ and PX have a Brillouin-function-like dependence on B and T, verifying the presence of paramagnetism in Ag+-doped CdSe NPLs. The observed light-induced magnetism is attributed to the transformation of nonmagnetic Ag+ ions into Ag2+, which have a nonzero magnetic moment. This work points to the possibility of incorporating these nanoplatelets into spintronic devices, in which light can be used to control the spin injection.