Magnetic Effect of Dopants on Bright and Dark Excitons in Strongly Confined Mn-Doped CsPbI3 Quantum Dots

• Published in: Nano letters Vol. 21; no. 22; pp. 9543 - 9550
• Main Authors: Qiao, Tian, Liu, Xiaohan, Rossi, Daniel, Khurana, Mohit, Lin, Yulin, Wen, Jianguo, Cheon, Jinwoo, Akimov, Alexey V, Son, Dong Hee
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.11.2021
• Subjects: dark exciton; exciton dynamics; Magnetic doping; NANOSCIENCE AND NANOTECHNOLOGY; perovskite; quantum dot
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.1c03114

We investigated the magnetic effect of Mn2+ ions on an exciton of Mn-doped CsPbI3 quantum dots (QDs), where we looked for the signatures of an exciton magnetic polaron known to produce a large effective magnetic field in Mn-doped CdSe QDs. In contrast to Mn-doped CdSe QDs that can produce ~100 T of magnetic field upon photoexcitation, manifested as a large change in the energy and relaxation dynamics of a bright exciton, Mn-doped CsPbI3 QDs exhibited little influence of a magnetic dopant on the behavior of a bright exciton. Furthermore, a μs-lived dark exciton in CsPbI3 QDs showed 40% faster decay in the presence of Mn2+, equivalent to the effect of ~3 T of an external magnetic field. While further study is necessary to fully understand the origin of the large difference in the magneto-optic property of an exciton in two systems, we consider that the difference in antiferromagnetic coupling of the dopants is an important contributing factor.