Light-Induced Paramagnetism in Colloidal Ag+-Doped CdSe Nanoplatelets

Arman Najafi; Manoj Sharma; Savas Delikanli; Arinjoy Bhattacharya; Joseph R Murphy; James Pientka; Ashma Sharma; Alexander P Quinn; Onur Erdem; Subash Kattel; Yusuf Kelestemur; Maksym V Kovalenko; William D Rice; Hilmi Volkan Demir; Athos Petrou

doi:10.1021/acs.jpclett.1c00398

Light-Induced Paramagnetism in Colloidal Ag⁺-Doped CdSe Nanoplatelets

J Phys Chem Lett. 2021 Mar 25;12(11):2892-2899. doi: 10.1021/acs.jpclett.1c00398. Epub 2021 Mar 16.

Authors

Arman Najafi¹, Manoj Sharma^{2

3}, Savas Delikanli^{2

3}, Arinjoy Bhattacharya¹, Joseph R Murphy^{4

5}, James Pientka⁶, Ashma Sharma², Alexander P Quinn¹, Onur Erdem³, Subash Kattel⁵, Yusuf Kelestemur^{7

8}, Maksym V Kovalenko^{7

9}, William D Rice⁵, Hilmi Volkan Demir^{2

3}, Athos Petrou¹

Affiliations

¹ Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, United States.
² Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798.
³ Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey.
⁴ Department of Chemistry and Physics, Southeast Missouri State University, Cape Girardeau, Missouri 63701, United States.
⁵ Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States.
⁶ Department of Physics, St. Bonaventure University, St. Bonaventure, New York 14778, United States.
⁷ Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland.
⁸ Department of Metallurgical and Materials Engineering, Atilim University, Ankara 06830, Turkey.
⁹ Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.

PMID: 33724845
DOI: 10.1021/acs.jpclett.1c00398

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 (P_X) and the exciton Zeeman splitting (ΔE_Z) were recorded as a function of the magnetic field (B) and temperature (T). Both ΔE_Z and P_X 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.