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 that of 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, annealing at 85 °C), the MADR-treated film exhibits enlarged grains, reduced trap density, and improved crystallinity, resulting in an ∼10³ order photocurrent enhancement from 1.02 × 10⁻⁷ to 4.5 × 10⁻⁴ A cm⁻² at 5 V under 365 nm illumination (125 mW cm⁻²). This MADR approach on blade-coated films provides scalable, high-quality perovskite films with low thermal budget and broad substrate compatibility, offering a versatile route for radiation detection and optoelectronic devices.