Synergistic Electron Density and Oxygen Defect Regulation in Fluorite High-Entropy Oxides for Superior Ionizing Radiation Shielding

en Lightweight and lead-free radiation shielding materials remain urgently needed. This work designed a fluorite high-entropy oxide (FHEO) system through a combined computational–experimental route. Density functional theory based on special quasi-random structures was used to identify thermodynamically stable fluorites from a wide compositional space. Their γ-ray attenuation potential in polypropylene (PP) composites was then evaluated, and the best candidates were selected for ultrafast Joule-heating synthesis. Guided by this workflow, LaSm-1000/PP composite showed broad-spectrum shielding performance and surpassed PbO/PP at identical loadings. Its linear attenuation coefficients were 5.67, 0.48, 0.38, and 0.34 cm −1 at 59.5, 662, 1173, and 1332 keV, respectively. X-ray photoelectron spectroscopy and projected density of states revealed an electron density–oxygen defect synergy in optimized FHEO. Lattice distortion and uniform cation distribution suppressed oxygen defects, stabilized Bi 3+ and W 6+ , and broadened O 2p states. These electronic features enhanced photoelectric absorption at low energies and promoted Compton scattering at medium and high energies. The proposed design route provides an efficient and scalable strategy for next-generation lead-free radiation shielding materials. 摘要 zh 轻质、无铅的辐射屏蔽材料仍具有迫切的应用需求。本研究通过计算模拟与实验相结合的策略 , 设计了一系列萤石结构高熵氧化物 ( FHEOs ) 。基于特殊准随机结构的密度泛函理论计算 , 从十种成分中筛选出具有热力学稳定性的萤石型高熵氧化物 , 并通过蒙特卡洛模拟进一步评估其在聚丙烯 ( PP ) 复合材料中的γ射线衰减潜力 , 选取最优组分进行超快焦耳加热合成。在该设计流程指导下制备的LaSm-1000/PP复合材料表现出优异的宽能区辐射屏蔽性能 , 相同填料含量的性能优于PbO/PP体系。在59.5、662、1173和1332 keV能量下的线性衰减系数分别为5.67、0.48、0.38和0.34 cm −1 。X射线光电子能谱与投影态密度分析表明 , FHEOs体系中存在显著的电子密度–氧缺陷协同效应。晶格畸变与均匀的阳离子分布有效抑制了氧缺陷的形成 , 稳定了Bi 3+ 和W 6+ 的高价态 , 并拓宽了O 2p能带结构。这种电子结构特征在低能区增强了光电吸收过程 , 在中高能区促进了康普顿散射行为 , 从而实现了宽能谱γ射线的高效衰减。本研究提出的计算–模拟–实验一体化设计路线 , 为新一代无铅辐射屏蔽材料的高效开发与规模化制备提供了一种可行且具有推广价值的策略。