The optical and electronic properties of cesium lead halide perovskite nanocrystals are dictated by the band-edge exciton, whose physics is not elucidated. Here, the authors unveil its fine structure and demonstrate that the ground dark singlet state promotes the creation of biexcitons at low temperatures and thus correlated photon pairs.
- Philippe Tamarat
- Lei Hou
- Brahim Lounis
