Locking Metastable Topological Domains in Nematic Liquid Crystal Pi Cells

Abstract The problem of stabilizing and switching between transient states in a Pi cell has long challenged the liquid crystal display industry. Here, distinct topological domain regions within nematic liquid crystal (LC) pi‐cells are manipulated by controlling the nucleation and growth processes in ways that indefinitely stabilize LC states that are traditionally only observed as being metastable. Photo‐polymerization under controlled voltage imprints patterns corresponding to the bend and splay states and impedes nucleation across topological regimes, ensuring long‐term maintenance of complex director configurations. This methodology results in a high‐speed Pi cell shutter, enabling rapid transitions between topologically compatible bend and twisted states while completely suppressing nucleation into the topologically incompatible splay state. Moreover, bistability is established through a combination of thermal and voltage control, thereby enabling a range of practical applications that capitalize on these stable configurations. Q‐tensor simulations corroborate the experiments, demonstrating the temporal and spatial dynamics of nucleation and topological state stabilization. By precisely controlling the locking of director states across varying topologies, a bistable LC device is constructed with a voltage‐driven hysteresis loop. These findings represent a significant advancement in the manipulation of LC device topologies, opening the door to advanced functionalities and broader applications for Pi cells.