Exploring the fine-structure of cesium lead bromide (CsPbBr₃) perovskite nanocrystals (NCs) is not only vital to fundamental understanding of recombination mechanism of exciton but also crucial for improving the performance of quantum light emitters and spintronic devices. Herein, utilizing low-temperature magneto-photoluminescence (PL) measurement, we provide the direct PL spectral feature of the dark exciton in CsPbBr₃ single crystal, and demonstrate that the singlet dark exciton is located ∼20 meV below the triplet bright exciton. Furthermore, no significant polarization effect was measured from magnetic-polarization method, indicating that there is no spin selectivity for dark exciton.

探索溴化铯铯（CsPbBr ₃）钙钛矿纳米晶体（NCs）的精细结构，不仅对激子复合机理的基本理解至关重要，而且对改善量子发光体和自旋电子器件的性能也至关重要。在此，我们利用低温磁光致发光（PL）测量，提供了CsPbBr ₃单晶中暗激子的直接PL光谱特征，并证明了单重态暗激子位于三重态亮激子下方约20 meV。此外，通过磁极化方法未测量到明显的极化效应，这表明对于暗激子没有自旋选择性。