Copper Iodide Inks for High-Resolution X-ray Imaging Screens

Copper-based halide scintillators have attracted considerable interest because of their high light yields, low detection limits, low toxicity, and moderate fabrication conditions. Here, we synthesized two Cu(I) iodide inks, comprising zero-dimensional Cu4I6(L1)2 nanoparticles (L1 = 1-propyl-1,4-diazabicyclo2.2.2octan-1-ium) and one-dimensional Cu4I6(L2)2 nanorods (L2 = 4-dimethylamino-1-ethylpyridinium) for X-ray imaging application. The Cu4I6(L1)2 nanoparticles and Cu4I6(L2)2 nanorods exhibited broadband green and yellow emission with an ultrahigh photoluminescence quantum yield of 95.3% and 92.2%, respectively. Consequently, the two Cu(I) iodide ink-based X-ray screens exhibited low detection limits of 96.4 and 102.1 nGy s–1, respectively, which are approximately 55 times lower than the dose required for standard medical diagnosis (5.5 μGy s–1). Importantly, both the scintillation screens exhibited extraordinary X-ray imaging resolutions exceeding 30 lp mm–1, more than double those of the conventional CsI:Tl and Ga2O2S:Tb scintillators. This study provides a new avenue for exploring high-resolution X-ray imaging screens on the basis of Cu-based halide ink for medical radiography and nondestructive detection.