具有高效发光性能的亚铜卤化物纳米团簇应用于X-射线闪烁体

Near-unity broadband luminescent cuprous halide nanoclusters as highly efficient X-ray scintillators

闪烁体可以将高能辐射转化为可见光,作为一种光电功能材料已经广泛应用于各种放射探测领域.虽然三维Pb基钙钛矿纳米晶可以开发为X射线闪烁体材料,但是其较低的光产额和铅毒性问题在一定程度上限制了其应用.为解决这一问题,本文重点关注零维金属卤化物发光材料,合成了一系列基于孤立[Cu_(4)X_(6)]^(2−)纳米团簇的零维卤化物,并将其开发应用为闪烁体发光材料.在紫外线或蓝光激发下,该卤化物纳米团簇均显示出宽带光发射,发光颜色可覆盖绿色、橙色到红色,并且具有近乎100%的光量子产率和较大的Stokes位移(>1.3 eV).特别突出的是,该类卤化物纳米团簇由于较高的发光量子产率、较小的光学自吸收和较强的X射线衰减效率,表现出优异的X-射线闪烁发光性能,光产额最高可达到24,240 photons MeV−1.材料的闪烁发光强度与X射线剂量呈现线性关系,检测范围较宽,且检测极限(0.7563μGy_(air)s^(−1))远低于常规医学诊断所要求的计量(5.5μGy_(air)s^(−1)).X-射线成像结果表明该纳米团簇余晖衰减时间较短(1.3 ms),空间分辨率较高(14.83 lp mm^(−1)),在医学成像等领域具有潜在的应用价值.该项工作表明,亚铜卤化物纳米团簇具有高效、稳定、无毒、发光效率高等优点,有望成为一种优异的新型闪烁体发光材料.

X-ray scintillators as functional energy materials possess the powerful ability to convert high-energy radiation into visible light with wide applications in various nuclear radiation fields.In this regard,three-dimensional(3D)lead perovskite nanocrystal-based X-ray scintillators have attracted extensive attention,but their low light yield and serious toxicity extremely restrict their further applications.To address these issues,a family of 0D hybrid cuprous halides of A_(2)Cu_(4)X_(6)(A=PTPP,TPA;X=Br,I)based on discrete[Cu_(4)X_(6)]^(2−)nanoclusters were demonstrated as highly desirable lead-free scintillators.Upon excitation of both ultraviolet and blue light,these halide nanoclusters displayed that self-trapped excitons induced broadband light emissions from green to red with near-unity photoluminescent quantum yield(PLQY,93.1%)and large Stokes shifts(>1.3 eV).Significantly,the high PLQY,negligible self-absorption,and strong X-ray attenuation from[Cu_(4)X_(6)]^(2−)nanoclusters endowed them with extraordinary radioluminescence properties.The linear radioluminescence intensity response to a wide range of X-ray dose rates gave an acceptable detection limit of 0.7563μGyair s−1,which was lower than the required value for regular medical diagnostics(5.5μGyair s−1).X-ray imaging demonstrated an ultrahigh spatial resolution of 14.83 lp mm^(−1)and negligible afterglow(1.3 ms),showcasing potential applications in X-ray radiography.Overall,the combined superiorities of nontoxicity,high light yield,excellent stability,and good radiation hardness make cuprous halide nanoclusters excellent scintillators.