Topological polar textures on CsPbBr3 nanoplatelets

Polar topological textures like the bubble domains, flux–closures, and labyrinth etc., unlock functional responses in ferroic systems but are difficult to stabilize and control in chemically simple, solution–grown materials. Here we show that ultra–thin, large–area CsPbBr${}_3$ nanoplatelets host room–temperature ferroelectric bubble domains whose characteristic size is tunable by thickness. Using contact–resonance piezoresponse force microscopy (PFM) across 125ñm–2~$\mu$m, we observe a systematic decrease in domain size with decreasing thickness, consistent with a depolarization–field controlled stability window. Repeated scanning transforms bubbles into labyrinthine patterns, indicating metastability under weak mechanical/electrical perturbations. Upon heating, bubbles evolve into labyrinths and vanish at $T_C\text{\hspace{0.17em}⁣}\approx \text{\hspace{0.17em}⁣}{90}^{\circ }$C, with domain nucleation recovered on cooling. These results establish a controllable platform for polar topology in a stable, stochiometric perovskite grown via a solvothermal route, and clarify how electrical boundary conditions (set by thickness and temperature) govern texture selection. The thickness–tunable polar textures identified here offer a route to engineer domain–wall–mediated functionalities in halide perovskites.