Room temperature collective blinking and photon bunching from CsPbBr3 quantum dot superlattice

superlattices exhibit distinct two-level blinking, and demonstrate photon bunching with a degree of up to 3.9. Time-resolved photoluminescence and super-resolution imaging reveal long lifetime components, and emission spatially confined to regions tens of nanometers in size, observations consistent with long-range exciton migration to a localized energy trap within the superlattice. Power-dependent degree of bunching and analysis of the bunching dynamics point to biexciton-exciton cascade emission as the origin of photon bunching. These findings establish perovskite QD superlattices as a promising platform for room-temperature collective optical phenomena.