Chen Guirong, Dai Hongliang, Zhu Zeng-Kui, Wu Jianbo, Yu Panpan, Zeng Ying, Zheng Yingying, Xu Lijun, Luo Junhua
School of Chemistry and Chemical Engineering, Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, Nanchang, Jiangxi, 330022, P. R. China.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China.
Small. 2024 Jul;20(30):e2312281. doi: 10.1002/smll.202312281. Epub 2024 Mar 8.
The low-toxic and environmentally friendly 2D lead-free perovskite has made significant progress in the exploration of "green" X-ray detectors. However, the gap in detection performance between them and their lead-based analogues remains a matter of concern that cannot be ignored. To reduce this gap, shortening the interlayer spacing to accelerate the migration and collection of X-ray carriers is a promising strategy. Herein, a Dion-Jacobson (DJ) lead-free double perovskite (4-AP)AgBiBr (1, 4-AP = 4-amidinopyridine) with an ultra-narrow interlayer spacing of 3.0 Å, is constructed by utilizing π-conjugated aromatic spacers. Strikingly, the subsequent enhanced carrier transport and increased crystal density lead to X-ray detectors based on bulk single crystals of 1 with a high sensitivity of 1117.3 µC Gy cm, superior to the vast majority of similar double perovskites. In particular, the tight connection of the inorganic layers by the divalent cations enhances structural rigidity and stability, further endowing 1 detector with ultralow dark current drift (3.06 × 10 nA cm s V, 80 V), excellent multiple cycles switching X-ray irradiation stability, as well as long-term environmental stability (maintains over 94% photoresponse after 90 days). This work brings lead-free double perovskites one step closer to realizing efficient practical green applications.
低毒且环保的二维无铅钙钛矿在“绿色”X射线探测器的探索方面取得了重大进展。然而，它们与含铅类似物之间在探测性能上的差距仍然是一个不可忽视的问题。为了缩小这一差距，缩短层间距以加速X射线载流子的迁移和收集是一种很有前景的策略。在此，通过利用π共轭芳香间隔基构建了一种层间距超窄（3.0 Å）的狄龙-雅各布森（DJ）无铅双钙钛矿（4-AP）AgBiBr（1，4-AP = 4-脒基吡啶）。引人注目的是，随后增强的载流子传输和增加的晶体密度使得基于1的块状单晶的X射线探测器具有1117.3 µC Gy cm的高灵敏度，优于绝大多数类似的双钙钛矿。特别是，二价阳离子对无机层的紧密连接增强了结构刚性和稳定性，进一步赋予1探测器超低的暗电流漂移（3.06×10 nA cm s V，80 V）、优异的多次循环切换X射线辐照稳定性以及长期环境稳定性（90天后保持超过94%的光响应）。这项工作使无铅双钙钛矿更接近实现高效实用的绿色应用。
