Optimized Grain Growth in CsPbBr3 Thick Films Using Mist-Assisted Dissolution-Recrystallization for Enhanced Optoelectronic Performance

Abstract

All-inorganic metal halide perovskite (MHP) thick films offer exceptional promise for photodetector applications (visible, UV, X-ray and gamma-ray) due to the stability of inorganic compositions and enhanced radiation absorption of thick-film architectures. However, their performance is often limited, compared to their single crystal counterparts, due to small grain sizes and high grain boundary densities which introduce trap states that reduce device efficiency. Here, we introduce a mist-assisted dissolution–recrystallization (MADR) process to enhance the microstructure of blade-coated CsPbBr3 thick films (~200 µm). Applying a CsPbBr3/DMSO mist at controlled concentrations (0.1–0.4 M) followed by low-temperature annealing (60–110 °C) drives a 3.8-fold increase in average grain size from 0.83 ± 0.28 to 3.19 ± 1.57 µm. Under optimal conditions (0.1 M mist, 85 °C anneal), the MADR-treated film exhibits enlarged grains, reduced trap density, and improved crystallinity, resulting in a ~103 photocurrent enhancement from 1.02 × 10⁻7 to 4.5 × 10⁻4 A/cm2 at 5 V under 365 nm illumination (125 mW/cm2). This MADR approach on blade coated films provides scalable fabrication, high-quality perovskite films with low thermal budget and broad substrate compatibility, offering a versatile route to high-quality perovskite thick films for radiation detection and optoelectronic devices.