This article reports the flux composition optimization, crystal growth, and optical spectroscopic properties of LaBSiO₅ and Eu³⁺-substituted LaBSiO₅ crystals. The mixture design technology was successfully applied in the crystal growth area for the first time. By the direction of mixture design method, the composition of a complex flux comprising LaBO₃, SiO₂, and Li₂MoO₄ was optimized and used for growth of LaBSiO₅ crystals. A large size of Eu³⁺-substituted LaBSiO₅ crystal with dimension of 12 × 10 × 8 mm³ has been prepared by top-seeded solution growth method. As far as we know, it is the first report that active ion-substituted LaBSiO₅ bulk crystal was obtained from an environmentally friendly flux without fluorides. The optical spectroscopy and electronic transition properties of Eu³⁺-substituted LaBSiO₅ crystals are studied thoroughly by analyzing the excitation and emission spectra and luminescence decay curves. The luminescence of Eu³⁺ ions are characteristic of intense red light emission corresponding to transitions of ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂. Meanwhile, the splitting of emission bands mentioned above is apparent because of the lower symmetry of lattice sites where the active ion locates. Furthermore, the symmetry properties of the lattice sites where Eu³⁺ ions locate are investigated by using Judd–Ofelt theory. The value of intensity parameters of Eu³⁺-substituted LaBSiO₅ ranges from 4.19 to 4.89 when the Eu³⁺ concentration varies.

中文翻译：

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大尺寸LaBSiO ₅和Eu ³⁺取代的LaBSiO ₅晶体的通量探索，生长和光谱性质

本文报道了LaBSiO ₅和Eu ³⁺取代的LaBSiO ₅晶体的通量组成优化，晶体生长和光谱性质。混合物设计技术首次成功地应用于晶体生长领域。按照混合物设计方法的指导，优化了由LaBO ₃，SiO ₂和Li ₂ MoO ₄组成的复合助熔剂的组成，并将其用于LaBSiO ₅晶体的生长。尺寸为12×10×8 mm ^3的大尺寸Eu ³⁺取代LaBSiO ₅晶体已经通过种顶溶液生长法制备。据我们所知，这是第一个报道，活性离子取代的LaBSiO ₅块状晶体是从无氟的环保助熔剂中获得的。通过分析激发和发射光谱以及发光衰减曲线，对Eu ³⁺取代的LaBSiO ₅晶体的光谱学和电子跃迁性质进行了深入研究。Eu ³⁺离子的发光具有强烈的红色发光特性，对应于⁵ D ₀ → ⁷ F ₁和⁵ D ₀ → ⁷ F的跃迁₂。同时，由于活性离子所处的晶格位点的对称性较低，因此上述发射带的分裂是明显的。此外，使用Judd-Ofelt理论研究了Eu ³⁺离子所处的晶格位点的对称性。当Eu ³⁺浓度变化时，Eu ³⁺取代的LaBSiO ₅的强度参数的值在4.19至4.89的范围内。