Wang Miaosheng, Zou Han, Zhang Jia, Wu Ting, Xu Hengxing, Haacke Stefan, Hu Bin
Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States.
Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67000 Strasbourg, France.
J Phys Chem Lett. 2020 May 7;11(9):3647-3652. doi: 10.1021/acs.jpclett.0c00842. Epub 2020 Apr 24.
This paper reports an extremely long spin relaxation time of optically polarized light-emitting states at room temperature in quasi-2D perovskites [(PEA)(MA)PbBr with = 5], when the long-range orbit-orbit interaction between excited states is developed through orbital polarization. Our studies found that the quasi-2D perovskite [(PEA)(MA)PbBr with = 5] demonstrates a long-range orbit-orbit interaction between excited states to conserve the spins of optically polarized light-emitting states, identified by the positive change on photoluminescence intensity (+ΔPL) in steady state upon switching the photoexcitation from linear to circular polarization. Meanwhile, the PL circular polarization (σσ - σσ) can maintain in nanosecond under fixed photoexcitation (σ). In contrast, the 2D/3D mixed perovskite ( > 5) shows a short-range orbit-orbit interaction between excited states through orbital magnetic dipoles, identified by the -ΔPL by switching from linear to circular photoexcitation. At the same time, the spin lifetime of light-emitting states becomes undetectable.
本文报道了在准二维钙钛矿[(PEA)(MA)PbBr ， = 5]中，当通过轨道极化发展激发态之间的长程轨道-轨道相互作用时，室温下光学极化发光态具有极长的自旋弛豫时间。我们的研究发现，准二维钙钛矿[(PEA)(MA)PbBr ， = 5]在激发态之间表现出长程轨道-轨道相互作用，以保持光学极化发光态的自旋，这通过在将光激发从线偏振切换为圆偏振时稳态光致发光强度的正向变化(+ΔPL)得以确定。同时，在固定光激发(σ)下，PL圆偏振(σσ - σσ)可在纳秒内保持。相比之下，二维/三维混合钙钛矿( > 5)通过轨道磁偶极子在激发态之间表现出短程轨道-轨道相互作用，这通过从线偏振光激发切换为圆偏振光激发时的-ΔPL得以确定。与此同时，发光态的自旋寿命变得无法检测到。
