Efficient Direct X‑ray Detection and Imaging Based on a Lead-Free Electron Donor–Acceptor MOF

• Published in: ACS applied materials & interfaces Vol. 16; no. 7; pp. 9002 - 9011
• Main Authors: Mi, Jiarong, Li, Qianwen, Li, Baoyi, Wang, Wenfei, Wang, Shuaihua, Zheng, Fakun, Guo, Guocong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21.02.2024
• Subjects: Functional Inorganic Materials and Devices; electron donor−acceptor; semiconductor; lead-free; X-ray direct detection and imaging; metal−organic frameworks
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c16712

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, Cu2I2(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 cm2 V–1 and a high detection sensitivity of 73.1 μC Gyair –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 Gyair. 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 Gyair –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.