Visible colorimetric dosimetry of UV and ionizing radiations by a dual-module photochromic nanocluster

Radiation dosimeters displaying conspicuous response of irradiance are highly desirable, owing to the growing demand of monitoring high-energy radiation and environmental exposure. Herein, we present a case of dosimetry based on a discrete nanocluster, [Th-6(OH)(4)(O)(4)(H2O)(6)](TPC)(8)(HCOO)(4).4DMF.H2O (Th-SINAP-100), by judiciously incorporating heavy Th-6 polynuclear centers as radiation attenuator and organic linkers as photo-responsive sensor. Interestingly, dual-module photochromic transitions upon multiple external stimuli including UV, beta -ray, and gamma -ray are integrated into this single material. The striking color change, and more significantly, the visible color transition of luminescence in response to accumulating radiation dose allow an on-site quantitative platform for naked-eye detection of ionization radiations over a broad range (1-80 kGy). Single crystal X-ray diffraction and density functional theory calculations reveal that the dual-module photochromism can be attributed to the (TPC)-> pi*(TPC) intermolecular charge transfer driven by enhanced pi-pi stacking interaction between the adjacent TPC moieties upon irradiation. Radiation dosimeters that measure ionizing radiations over a broad range and allow for direct readout are desirable. Here, the authors present a dual-mode photochromic thorium-based metal-organic nanocluster that enables direct visible colorimetric dosimetry of UV, beta -ray, and gamma -ray radiation.

Automated summary

This study presents a dual-mode photochromic thorium-based metal-organic nanocluster for direct visible colorimetric dosimetry of UV, beta-ray, and gamma-ray radiation, allowing for quantification of ionizing radiations over a broad range. The material integrates dual-module photochromism and enables on-site detection of radiation dose changes through visible color transitions.