Ultrafast spectral analysis on the spin relaxation dynamics in strongly confined CsPbBr3 nanocrystals
Zixiang Zhou1, Rongxin Zhang1, Lei Wang1
1Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Hubei University of Arts and Science, Xiangyang, China.
Abstract:
Owing to the facile optical orientation of spin-polarized states in lead halide perovskites (LHPs), extensive efforts have been devoted to their efficient spin detection and manipulation for applications of spintronics or quantum information science. Among usual characterization methods for exploring the exciton spin dynamics, the circularly polarized transient absorption (CPTA) spectroscopy is an important one. Herein, three small-sized CsPbBr3 nanocrystals (NCs) (3.2-4.3 nm) are synthesized and their spin relaxation dynamics are analyzed by employing CPTA spectroscopy. The results reveal that for CsPbBr3 NCs with strong quantum confinement, expecially for the 3.2 nm CsPbBr3, the spin relaxation time derived from the second photo-induced absorption (PA2) kinetics at larger wavelength is much longer than those from the first exciton bleach (XB) and the first photo-induced absorption (PA1). In other words, the PA2 kinetics can reflect more accurate spin relaxation process in strongly confined NCs. This phenomenen can be attributed to the dominant Coulomb interaction between the band edge excitons for PA2 kinetics, while the other two kinetics of XB and PA1 are more sensitive to hot exciton relaxation. Considering the common issues that inhomogeneity generally exists in small-sized NCs due to difficult synthesis, this study could provide further insight for exploring the spin relaxation dynamics by CPTA spectroscopy in strongly confined LHPs NCs and benefit related applications in spintronics or quantum information science.
More Related Videos
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
Atomic Nuclei: Types of Nuclear Relaxation
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
NMR Spectroscopy: Spin–Spin Coupling
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...


