Tailored molecular for ultra-stability and biocompatible pseudohalide metal-free perovskite towards X-ray detectors with record sensitivity

• Published in: Npj flexible electronics Vol. 8; no. 1; pp. 46 - 10
• Main Authors: Lei, Yutian, Yin, Mengying, Shi, Chang, Wu, Lingxi, Peng, Guoqiang, Xu, Youkui, Wang, Haoxu, Tang, Rongbing, Li, ZhenHua, Jin, Zhiwen
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28-07-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301; 639/301/1005; Absorption cross sections; Biocompatibility; Bonding strength; Chemical bonds; Chemistry and Materials Science; Coordination; Cost effectiveness; Covalent bonds; Crystal structure; Electronics and Microelectronics; Energy gap; Hydrogen; Hydrogen bonding; Instrumentation; Ion migration; Materials Science; Molecular dynamics; Optical and Electronic Materials; Perovskites; Polymer Sciences; Radiation; Sensitivity; Sensors; Single crystals; Stability; Theoretical physics; X ray absorption; X ray detectors; X-rays
• ISSN: 2397-4621; 2397-4621
• DOI: 10.1038/s41528-024-00330-2

The emerging pseudohalide metal-free perovskite (pseudohalide–MFPs) X-ray detector caters to the demands of timely mobile diagnosis owing to its lightweight, flexibility, and cost-effectiveness. However, the performance of these devices is severely limited by poor X-ray absorption, ultra-wide band gap, relative instability, and their unknown biotoxicity. Herein, we construct heavy atom covalent bonds (C–Br/Cl) on the A-site organic cation to reinforce component coordination to modulate X-ray absorption and band gap in pseudohalide–MFPs and further enhance its stability. Molecular dynamics simulations demonstrate that the introduction of halogen atoms can strengthen hydrogen bonding interactions, thereby improving the coordination between different components. The resultant (MDABCOBr)–NH
4
(BF
4
)
3
(MDABCO = N-methyl-N’-diazabicyclo[2.2.2]octonium) single crystal significantly increases X-ray absorption cross-section and crystalline density (from 1.728 to 1.950 g cm
−3
), and synergistically realizes the band nature modulation (from 7.4 to 5.5 eV) and enhanced ionic migration inhibition (628 meV) with optimized stability. As such, our X-ray detectors realized a sensitivity of 2377 μC Gy
air
−1
 cm
−2
, an ultralow detection limit of 50.1 nGy
air
 s
−1
, and impressive operation stability. Moreover, cytotoxicity assay confirmed the compatibility of pseudohalide metal-free perovskite. Finally, within this framework, we successfully fabricate the (MDABCOBr)–NH
4
(BF
4
)
3
-based flexible device to create an ideal in vitro wearable X-ray detection.