Morad Viktoriia, McCall Kyle M, Sakhatskyi Kostiantyn, Lehmann Eberhard, Walfort Bernhard, Losko Adrian S, Trtik Pavel, Strobl Markus, Yakunin Sergii, Kovalenko Maksym V
Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland.
Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
ACS Photonics. 2021 Nov 17;8(11):3357-3364. doi: 10.1021/acsphotonics.1c01348. Epub 2021 Oct 25.
The fast neutron imaging technique with recoil proton detection harbors significant potential for imaging of thick, large-scale objects containing high-Z elements. However, the challenge to find efficient fast neutron scintillators with high spatial resolution is ongoing. The list of requirements for such scintillators is long and demanding: a proton-rich, scattering-free material combining high light yield with the absence of light reabsorption. To meet these challenges, we look for a suitable material among a rising class of 0D organic-inorganic Pb(II) halide hybrids. The use of large organic cations, eg., trihexyltetradecylphosphonium, results in room-temperature ionic liquids that combine highly Stokes-shifted (up to 1.7 eV), reabsorption-free, and efficient emission (photoluminescence quantum yield up to 60%) from molecularly small and dense (PbX molar fraction up to 0.33) emitting centers. We investigate the optical properties of the resulting ionic liquids and showcase their utility as fast neutron imaging scintillators. Concomitantly with good light yield, such fast-neutron scintillators exhibit both higher spatial resolution and lower γ-ray sensitivity compared with commercial ZnS:Cu-based screens.
采用反冲质子探测的快中子成像技术在对包含高Z元素的厚大尺寸物体进行成像方面具有巨大潜力。然而，寻找具有高空间分辨率的高效快中子闪烁体仍然是一项持续的挑战。此类闪烁体的要求繁多且苛刻：一种富含质子、无散射的材料，要兼具高光产额且不存在光重吸收现象。为应对这些挑战，我们在一类新兴的0D有机 - 无机卤化铅（II）杂化物中寻找合适的材料。使用大有机阳离子，例如三己基十四烷基鏻，可得到室温离子液体，这些离子液体结合了来自分子小且密集（PbX摩尔分数高达0.33）的发射中心的高度斯托克斯位移（高达1.7 eV）、无重吸收且高效的发射（光致发光量子产率高达60%）。我们研究了所得离子液体的光学性质，并展示了它们作为快中子成像闪烁体的效用。与商业的基于ZnS:Cu的屏幕相比，此类快中子闪烁体在具有良好光产额的同时，还展现出更高的空间分辨率和更低的γ射线灵敏度。
