Zero-Dimensional Cs(3)BiX(6) (X = Br, Cl) Single Crystal Films with Second Harmonic Generation

The development of atomically thin single crystal films is necessary to potential applications in the 2D semiconductor field, and it is significant to explore new physical properties in low-dimensional semiconductors. Since, zero-dimensional (0D) materials without natural layering are connected by strong chemical bonds, it is challengeable to break symmetry and grow 0D Cs(3)BiX(6) (X = Br, Cl) single crystal thin films. Here, we report the successful growth of 0D Cs(3)BiX(6) (X = Br, Cl) single crystal films using a solvent evaporation crystallization strategy. Their phases and structures are both well evaluated to confirm 0D Cs(3)BiX(6) (X = Br, Cl) single crystal films. Remarkably, the chemical potential dependent morphology evolution phenomenon is observed. It gives rise to morphology changes of Cs(3)BiBr(6) films from rhombus to hexagon as BiBr(3) concentration increased. Additionally, the robust second harmonic generation signal is detected in the Cs(3)BiBr(6) single crystal film, demonstrating the broken symmetry originated from decreased dimension or shape change.