Zero-Dimensional Cs3BiX6 (X = Br, Cl) Single Crystal Films with Second Harmonic Generation

<jats:title>Abstract</jats:title><jats:p>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<jats:sub>3</jats:sub>BiX<jats:sub>6</jats:sub> (X = Br, Cl) single crystal thin films. Here, we report the successful growth of 0D Cs<jats:sub>3</jats:sub>BiX<jats:sub>6</jats:sub> (X = Br, Cl) single crystal films using a solvent evaporation crystallization strategy. Their phases and structures are both well evaluated to confirm 0D Cs<jats:sub>3</jats:sub>BiX<jats:sub>6</jats:sub> (X = Br, Cl) single crystal films. Remarkably, the chemical potential dependent morphology evolution phenomenon is observed. It gives rise to morphology changes of Cs<jats:sub>3</jats:sub>BiBr<jats:sub>6</jats:sub> films from rhombus to hexagon as BiBr<jats:sub>3</jats:sub> concentration increased. Additionally, the robust second harmonic generation signal is detected in the Cs<jats:sub>3</jats:sub>BiBr<jats:sub>6</jats:sub> single crystal film, demonstrating the broken symmetry originated from decreased dimension or shape change.</jats:p>