Efficient Direct X-ray Detection and Imaging Based on a Lead-Free Electron Donor–Acceptor MOF
Jiarong Mi, Qianwen Li, Baoyi Li, Wenfei Wang, Shuai‐Hua Wang, Fa‐Kun Zheng, Guo‐Cong Guo
Abstract
Metal–organic frameworks (MOFs) have recently gained extensive attention as potential materials for direct radiation detection due to their strong radiation absorption, long-range order, and chemical tunability. However, it remains challenging to develop a practical MOF-based X-ray direct detector that possesses high X-ray detection efficiency, radiation stability, and environmental friendliness. The integration of donor–acceptor (D–A) pairs into crystalline MOFs is a powerful strategy for the precise fabrication of multifunctional materials with unique optoelectronic properties. Herein, a new lead-free MOF, Cu 2 I 2 (TPPA) ( CuI-TPPA, TPPA = tris[4-(pyridine-4-yl)phenyl]amine), with a 6-fold interpenetrated structure is designed and synthesized based on the electron donor–acceptor strategy. CuI-TPPA has a large mobility-lifetime ( μτ ) product of 5.8 × 10 –4 cm 2 V –1 and a high detection sensitivity of 73.1 μC Gy air –1 cm –2, surpassing that of commercial α -Se detectors. Moreover, the detector remains fairly stable with only a 2% reduction in photocurrent under continuous bias irradiation conditions with a total dose of over 42.83 Gy air . The CuI-TPPA /poly(vinylidene fluoride) flexible composite X-ray detector films are successfully manufactured with different thicknesses. Through multifaceted assessments, the optimal thickness is found with a high detection sensitivity of up to 143.6 μC Gy air –1 cm –2 . As proof-of-concept, 11 × 9 pixelated X-ray detectors are fabricated on the same composite film to realize X-ray direct imaging. This work opens up potential applications of MOFs in environmentally friendly and wearable devices for direct X-ray detection and imaging.