Magnetic-brightening and control of dark exciton in CsPbBr3 perovskite

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 similar to 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.