Liquid exfoliation has been extremely popular in the domain of 2D materials especially in the fast-growing area of MXene and conventional systems such as graphene. The popularity of this method lies in the simplistic route and large-scale production of product which is few atomic layers thick providing immense opportunities for nano-device fabrication. Hence, it is very much viable to be used in real applications. [1] Traditionally, this method required the system under study to be structurally layered 2D system as the principle lies in subjecting the 2D system to large force dispensed by the probe sonication which results in detaching the layers due to termination of the Van der Waals forces.  In recent times, researchers have successfully exfoliated 3D materials such as αFe2O3 which brought forth a new layered material ‘hematene’ which exhibits enhanced performance in energy devices. [2]  Within the family of hybrid perovskites, the route of liquid exfoliation has thus far been explored to yield uniform, large quantity, stable, and luminescent nanoparticles. The studies using this technique for synthesizing hybrid perovskites has been largely restricted to the bottom-up approach wherein the precursors are probe sonicated together to yield the desired hybrid perovskites such as MAPbX3 and CsPbX3 (X= I, Br, Cl). 

For a top-down approach, the hybrid perovskite single crystals are subjected to probe sonication within an appropriate environment for understanding the underlying mechanics of its exfoliation through the vibration force provided by the probe. It also provides an insight into basics of perovskite structure chemistry as we study the breaking down of perovskite single crystals into nanoparticles. In this work, all inorganic halide-based 3D perovskite such as CsPbBr3 is probe sonicated in absence of a ligand or capping agent. This results in nanocrystals and quantum dots which are chemically stable and emit blue emission. With a systematic approach, we vary two of the probe sonication parameters (solvent and duration) and try to understand the nuances involved in mechanical breaking down on a 3D perovskite. The PL emission studies is indicative of emission centers through the different emission centers (n= 1 to 7) arising from free excitons and localized/ trapped excitons in seen for the first time at room temperature. [3,4] This basic study provides a clear understanding of the inorganic halide- based system and its tendency of preferred orientation when forced into the quantum regime both structurally through HRTEM and spectroscopically by PL studies.