The optical properties of colloidal cesium lead halide perovskite (CsPbBr₃) nanocrystals are examined by time-resolved and polarization-resolved spectroscopy in high magnetic fields up to 30 T. We unambiguously show that at cryogenic temperatures the emission is dominated by recombination of negatively charged excitons with radiative decay time of 300 ps. The additional long-lived emission, which decay time shortens from 40 down to 8 ns and in which the decay time shortens and relative amplitude increases in high magnetic fields, evidences the presence of a dark exciton. We evaluate g-factors of the bright exciton g_X = +2.4, the electron g_e = +2.18, and the hole g_h = −0.22.

中文翻译：

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高磁场显示CsPbBr ₃钙钛矿纳米晶体中的带负电和暗激子

在高达30 T的高磁场中，通过时间分辨和极化分辨光谱法研究了胶态卤化铯铯钙钛矿（CsPbBr ₃）纳米晶体的光学性质。我们明确地表明，在低温下，发射由负电荷的复合控制辐射衰减时间为300 ps的激子。在强磁场中，附加的长寿命发射（衰减时间从40 ns缩短到8 ns）以及衰减时间缩短和相对幅度增加，证明存在暗激子。我们评估了明亮激子的g因子g _X = +2.4，电子g _e = +2.18和空穴g _h。 = -0.22。