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

• Published in: Advanced functional materials Vol. 31; no. 13
• Main Authors: Wang, Chang‐Feng, Li, Haojin, Li, Mao‐Guang, Cui, Yu, Song, Xin, Wang, Qin‐Wen, Jiang, Jia‐Ying, Hua, Miao‐Miao, Xu, Qi, Zhao, Kui, Ye, Heng‐Yun, Zhang, Yi
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01-03-2021
• Subjects: Attenuation; Carrier lifetime; Carrier mobility; Crystals; Current carriers; Ferroelectric materials; Ferroelectricity; hybrid double perovskites; lead‐free perovskites; Materials science; molecular ferroelectrics; Multifunctional materials; Perovskites; Photosensitivity; Sensitivity; Single crystals; X‐ray detection
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202009457

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 Tc, small Ps, 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)4AgBiI8 (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 Tc up to 422 K and a large Ps of 10.5 μC cm−2. Moreover, due to a large X‐ray attenuation and efficient charge carrier mobility (μ)–charge carrier lifetime (τ) product, the crystal 1 also exhibits promising X‐ray response with a high sensitivity up to 188 μC·Gyair−1 cm−2 and a detection limit below 3.13 μGyair·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.
Ferroelectricity and X‐ray detection are realized in lead‐free hybrid double perovskite (DFPIP)4AgBiI8. It achieves excellent ferroelectricity (Tc = 422 K, Ps = 10.5 µC cm−2) and superior sensitivity of 188 µC·Gyair−1 cm−2 as an X‐ray detector. This finding will stimulate extensive research interest in photosensitive molecular ferroelectrics based on lead‐free double perovskites.