Emergence of Uranium as a Distinct Metal Center for Building Intrinsic X‐ray Scintillators

Abstract

The combination of high atomic number and high oxidation state in U materials gives rise to both high X-ray attenuation efficiency and intense green luminescence originating from ligand-to-metal charge transfer. These two features suggest that U materials might act as superior X-ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X-ray scintillation in a uranyl-organic framework (SCU-9) that is observable by the naked eye is reported. Combining the advantage in minimizing the non-radiative relaxation during the X-ray excitation process over those of inorganic salts of uranium, SCU-9 exhibits a very efficient X-ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X-ray intensity, and is comparable with that of commercially available CsI:Tl. SCU-9 possesses an improved X-ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl.

The sulfonate group as a ligand: a fine balance between hydrogen bonding and metal ion coordination in uranyl ion complexes

“…72 The solid-state photoluminescence quantum yield (PLQY) for 6 is 0.030 ± 0.001. Such low values have previously been found in other uranyl carboxylate complexes having a pale yellow color; 28 larger values, often associated with green coloring, are still unusual 75,76 (for comparison, the PLQY of uranyl nitrate hexahydrate measured under the same conditions is 24%).…”

Zero-, mono- and diperiodic uranyl ion complexes with the diphenate dianion: influences of transition metal ion coordination and differential UVI chelation

“…These are usual values for uranyl complexes having a pale yellow color, 18,44 larger values, often associated with yellowgreen coloring, being still rare. 54,55 . Only one diperiodic network has been obtained, with the fes topology, in which diaxially carboxylate-bound Cu(R,S-Me6cyclam) 2+ groups unite uranyl dimers into chains which are further assembled through bridging by other uranyl cations (complex 9).…”

Photosynergetic amplification of radiation input: from efficient UV induced cycloreversion to sensitive X-ray detection

“…35,[37][38][39][40][41] Most existing X-ray sensing compounds are based on expensive, toxic materials, usually including metal-organic frameworks or heavy metals which are difficult to process into commercial devices. [42][43][44][45][46][47][48][49] To counter this a number of organic based systems have been suggested; however, these all suffer from the difficulties of having to be paired with the solid-state electronic detection methods to produce a commercial device. Photochromic organic detectors may offer an alternative as they can report the presence of X-rays through easily observed colour changes, show relative hardness towards high energy photons, are easily recyclable and are much simpler to process.…”