Nonstoichiometry Promoted Solventless Recrystallization of a Thick and Compact CsPbBr3 Film for Real‐Time Dynamic X‐Ray Imaging

Abstract

Abstract Inorganic CsPbBr3 perovskite emerges as a promising material for the development of next‐generation X‐ray detectors. However, the formation of a high‐quality thick film of CsPbBr3 has been challenging due to the low solubility of its precursor and its high melting point. To address this limitation, a nonstoichiometry approach is taken that allows lower‐temperature crystallization of the target perovskite under the solventless condition. This approach capitalizes on the presence of excess volatile PbBr2 within the CsPbBr3 film, which induces melting point depression and promotes recrystallization of CsPbBr3 at a temperature much lower than its melting point concomitant with the escape of PbBr2. Consequently, thick and compact films of CsPbBr3 are formed with grains ten times larger than those in the pristine films. The resulting X‐ray detector exhibits a remarkable sensitivity of 4.2 × 104 µC Gyair−1 cm−2 and a low detection limit of 136 nGyair s−1, along with exceptional operational stability. Notably, the CsPbBr3‐based flat‐panel detector achieves a high resolution of 0.65 lp pix−1 and the first demonstration of real‐time dynamic X‐ray imaging for perovskite‐based devices.

Keywords

• aerosol–liquid–solid
• all‐inorganic perovskite
• Ostwald ripening
• real‐time dynamic imaging
• X‐ray detector