Revealing the Evolution of Quantum Confinement in the Growth of CsPbBr₃ Nanoplatelets by In Situ SAXS and Optical Spectroscopy

Cesium lead bromide perovskite nanoplatelets (NPLs) are promising candidates for next-generation light sources due to their exceptionally narrow photoluminescence linewidth, large exciton binding energies, and high oscillator strength. However, unlike their isotropic counterparts, the synthesis of NPLs remains challenging, primarily due to the difficulty of maintaining high chemical yield and stability while precisely controlling their thickness. These challenges stem from the inherently fast growth kinetics of NPLs in conventional synthetic approaches. Building on our previous success in slowing down the growth of isotropic nanocrystals, we have developed a novel synthesis strategy that enables slow growth of 2- or 3-monolayer-thick NPLs. This is achieved by employing ligands with varying binding energies and modulating precursor reactivity. To gain deeper understanding of their formation mechanism, we propose real-time monitoring of NPL nucleation and growth