Visible Colorimetric Dosimetry of UV and Ionizing Radiations by a Dual-Module Photochromic Nanocluster

Abstract

Radiation dosimeters displaying conspicuous response of irradiance are highly desirable over the recent decade owing to the growing demand of monitoring high-energy radiation and environmental exposure. Herein, we present the first case of dosimetry based on a discrete nanocluster by judicious incorporating heavy Th6 polynuclear centers as radiation attenuator and organic linkers as photo-responsive sensor to enhance chromic response. Rather unusual dual-module photochromic transitions upon multiple external stimuli including UV, β-ray, and γ-ray are integrated into this single material. The striking color change, and more significantly, the visible chromic 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). SC-XRD and DFT calculations revealed that the dual-module photochromism can be attributed to a unique π(TPC)→π*(TPC) intermolecular charge transfer (IeMCT) driven by enhanced π-π stacking interaction between the adjacent TPC moieties upon irradiations.