Homogeneous All-Inorganic Perovskite Films via High-Pressure Recrystallization

Metal halide perovskites are promising materials for optoelectronic applications owing to their outstanding optical and electronic properties.

Among them, all-inorganic perovskites such as CsPbBr$_3$ offer superior thermal and chemical stability.

However, obtaining high-quality CsPbBr$_3$ thin films via solution processing remains challenging due to the precursor's low solubility, and current additive or solvent engineering strategies are often complex and poorly reproducible.

High-pressure recrystallization has recently emerged as a promising route to improve film quality, yet its impact on film properties remains insufficiently explored.

Here, we systematically investigate the morphological, structural, and optical properties of CsPbBr$_3$ thin films prepared by high-pressure recrystallization, in comparison with standard non-recrystallized films.

Optimized recrystallization at 300 bar produces smooth, pinhole-free, single-phase 3D perovskite layers with sub-nanometer roughness, while the film thickness is precisely tunable via precursor concentration.

The process enhances both grain and crystallite sizes, leading to amplified spontaneous emission with a reduced excitation threshold and improved photostability.

Temperature-dependent X-ray diffraction further reveals the orthorhombic--tetragonal--cubic phase transition, consistent with single-crystal behavior.

This study provides fundamental insights into pressure-driven recrystallization and establishes a reproducible, scalable approach for fabricating high-quality CsPbBr$_3$ films for optoelectronic devices.