Centimeter-Sized Single Crystals of Two-Dimensional Hybrid Iodide Double Perovskite (4,4-Difluoropiperidinium)4AgBiI8 for High-Temperature Ferroelectricity and Efficient X-Ray Detection

Ferroelectricity and X-ray detection property have been recently implemented for the first time in hybrid bromide double perovskites. It sheds a light on achieving photosensitive and ferroelectric multifunctional materials based on 2D lead-free hybrid halide double perovskites. However, the low T-c, small P-s, and relatively low X-ray sensitivity in the reported bromide double perovskites hinder practical applications. Herein, the authors demonstrate a novel 2D lead-free iodide double perovskite (4,4-difluoropiperidinium)(4)AgBiI8 (1) for high-performance X-ray sensitive ferroelectric devices. Centimeter-sized single crystal of 1 is obtained and exhibits an excellent ferroelectricity including a high T-c up to 422 K and a large P-s of 10.5 mu C cm(-2). Moreover, due to a large X-ray attenuation and efficient charge carrier mobility (mu)-charge carrier lifetime (tau) product, the crystal 1 also exhibits promising X-ray response with a high sensitivity up to 188 mu C center dot Gy(air)(-1) cm(-2) and a detection limit below 3.13 mu Gy(air)center dot s(-1). Therefore, this finding is a step further toward practical applications of lead-free halide perovskite in high-performance photoelectronic devices. It will afford a promising platform for exploring novel photosensitive ferroelectric multifunctional materials based on lead-free double perovskites.

Automated summary

This study demonstrates the integration of ferroelectricity and X-ray detection property in hybrid bromide double perovskites for the first time. The authors successfully developed a novel lead-free iodide double perovskite for high-performance X-ray sensitive ferroelectric devices, showing promising X-ray response and excellent ferroelectric properties.