中国物理B ›› 2025, Vol. 34 ›› Issue (9): 96101-096101.doi: 10.1088/1674-1056/add678

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Site occupation of Al doping in Lu2SiO5: The role of ionic radius versus chemical valence

Xuejiao Sun(孙雪娇)1,2, Yu Cui(崔宇)1,2, Feng Gao(高峰)1,†, Zhongjun Xue(薛中军)2, Shuwen Zhao(赵书文)2, Dongzhou Ding(丁栋舟)2, Fan Yang(杨帆)3, and Yi-Yang Sun(孙宜阳)2,‡   

  1. 1 School of Physics, Changchun Normal University, Changchun 130032, China;
    2 State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China;
    3 Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Tianjin 300071, China
  • 收稿日期:2025-01-12 修回日期:2025-04-08 接受日期:2025-05-09 出版日期:2025-08-21 发布日期:2025-09-09
  • 通讯作者: Feng Gao, Yi-Yang Sun E-mail:5234110@qq.com;yysun@mail.sic.ac.cn
  • 基金资助:
    sincitillation materials|silicates|defects|first-principles calculations

Site occupation of Al doping in Lu2SiO5: The role of ionic radius versus chemical valence

Xuejiao Sun(孙雪娇)1,2, Yu Cui(崔宇)1,2, Feng Gao(高峰)1,†, Zhongjun Xue(薛中军)2, Shuwen Zhao(赵书文)2, Dongzhou Ding(丁栋舟)2, Fan Yang(杨帆)3, and Yi-Yang Sun(孙宜阳)2,‡   

  1. 1 School of Physics, Changchun Normal University, Changchun 130032, China;
    2 State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China;
    3 Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Tianjin 300071, China
  • Received:2025-01-12 Revised:2025-04-08 Accepted:2025-05-09 Online:2025-08-21 Published:2025-09-09
  • Contact: Feng Gao, Yi-Yang Sun E-mail:5234110@qq.com;yysun@mail.sic.ac.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2022YFB3503900) and the National Natural Science Foundation of China (Grant No. 12305212).

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摘要： Lu$_{2}$SiO$_{5}$:Ce (LSO:Ce) serving as a core material for radiation detectors, plays a crucial role in the design and development of positron emission tomography (PET) devices. Experiment has confirmed that low concentration of Al doping can significantly enhance the light yield, decay time, rise time, energy resolution, and afterglow level of the LSO:Ce crystals. The mechanisms regarding the lattice site occupancy of Al in LSO, while closely associated with the performance improvements, are not yet fully understood. Particularly, it is unclear either the ionic radius or the chemical valence plays a more critical role in determining the site occupancy. In this study, we utilized first-principles calculations based on density functional theory (DFT) to study the lattice site occupancy of Al in LSO crystals and to explore their impact on the electronic structure. Our results indicate that with changes in the growth environment, as reflected by the atomic chemical potentials, Al can occupy either the Si sites or the Lu$_2$ sites, and it is not inclined to occupy the Lu$_1$ sites. The doping of Al at the Si site introduces a shallow acceptor level, which may contribute to the suppression of trap concentration and affect the ratio of Ce$^{3+}$ to Ce$^{4+}$ within the crystal, thereby influencing its scintillation properties.

关键词: sincitillation materials, silicates, defects, first-principles calculations

Abstract: Lu$_{2}$SiO$_{5}$:Ce (LSO:Ce) serving as a core material for radiation detectors, plays a crucial role in the design and development of positron emission tomography (PET) devices. Experiment has confirmed that low concentration of Al doping can significantly enhance the light yield, decay time, rise time, energy resolution, and afterglow level of the LSO:Ce crystals. The mechanisms regarding the lattice site occupancy of Al in LSO, while closely associated with the performance improvements, are not yet fully understood. Particularly, it is unclear either the ionic radius or the chemical valence plays a more critical role in determining the site occupancy. In this study, we utilized first-principles calculations based on density functional theory (DFT) to study the lattice site occupancy of Al in LSO crystals and to explore their impact on the electronic structure. Our results indicate that with changes in the growth environment, as reflected by the atomic chemical potentials, Al can occupy either the Si sites or the Lu$_2$ sites, and it is not inclined to occupy the Lu$_1$ sites. The doping of Al at the Si site introduces a shallow acceptor level, which may contribute to the suppression of trap concentration and affect the ratio of Ce$^{3+}$ to Ce$^{4+}$ within the crystal, thereby influencing its scintillation properties.

Key words: sincitillation materials, silicates, defects, first-principles calculations

中图分类号:  (Defects and impurities in crystals; microstructure)

  • 61.72.-y
31.15.es (Applications of density-functional theory (e.g., to electronic structure and stability; defect formation; dielectric properties, susceptibilities; viscoelastic coefficients; Rydberg transition frequencies)) 29.40.Mc (Scintillation detectors)