Beyond Spin Coating: Homogeneous All-Inorganic Perovskite Films via High-Pressure Recrystallization

TL;DR

This paper demonstrates that high-pressure recrystallization significantly improves the quality and optoelectronic properties of all-inorganic CsPbBr$_3$ perovskite films, offering a scalable alternative to traditional solution processing methods.

Contribution

It introduces a systematic study of high-pressure recrystallization for CsPbBr$_3$ films, revealing its effectiveness in producing high-quality, stable, and tunable perovskite layers with enhanced optoelectronic performance.

Findings

Recrystallization at 300 bar yields smooth, pinhole-free films.

Enhanced grain and crystallite sizes improve emission and stability.

Phase transition behavior aligns with single-crystal characteristics.

Abstract

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.