Direct Correlation between Size, Photon Statistics, and Blinking Mechanisms in Single Cesium Lead Iodide Perovskite Nanocrystals.

The emission photon statistics and blinking dynamics of lead halide perovskite nanocrystals (PNCs) are strongly influenced by quantum confinement, Auger recombination (AR), and carrier trapping, yet their direct correlation with nanocrystal size remains unresolved. Here, we correlate size and optical properties of individual CsPbI3 PNCs by combining single-particle spectroscopy with atomic force microscopy. PNCs smaller than ∼12 nm exhibit pronounced quantum confinement, strong photon antibunching with g(2)(0) ≤ 0.2, and band-edge carrier blinking. As the size increases, the photoluminescence red shift weakens and g(2)(0) increases, approaching unity above ∼17 nm. Femtosecond transient absorption measurements reveal strongly suppresses AR in larger PNCs, while the dominant blinking mechanism shifts from the band-edge carrier to Auger blinking at ∼16-18 nm. These results establish design principles for stable quantum light emitters and size-tunable optoelectronic materials.