Polarized emission from single perovskite FAPbBr3 nanocrystals

Abstract Owing to the superior performance of lead-halide perovskites in various optoelectronic devices, their low-dimensional counterparts of quantum-confined nanocrystals (NCs) have started drawing intensive research attention. Here we report a systematic study on the optical properties of single FAPbBr3 NCs, which demonstrate high-purity single-photon emission, large absorption cross-section and narrow photoluminescence linewidth. Interestingly, linearly-polarized emission can be partially observed in single FAPbBr3 NCs at the room temperature, the degree of which is significantly enhanced at the cryogenic temperature. The above polarization phenomenon is attributed to the large energy-level splitting of the bright-exciton states, leading to efficient exciton recombination from the lowest state with a 1D dipole moment. This unique feature of linear polarization in the optical emission of single FAPbBr3 NCs has not only provided a deep understanding of their exciton energy-level structures, but also suggested potential polarization-oriented applications such as in photo-detectors, light-emitting diodes and lasers.